Finally, Some m4/3 MTF Testing: 25mm Prime Lens Comparison

January 9, 2018 · Roger Cicala · in Lenses and Optics , Resolution Tests , Technical Discussions

This blog is a little different. It’s geekier than most, of course. Also, I don’t use it to make income, and that makes it a bit scattered. A mainstream blog has to cover all the hot topics. I get to cover what I’m interested in at the moment. More importantly, I don’t have to cover everything, so you rarely see me writing about stuff I don’t understand.

Another benefit is I get to watch with great amusement as various Fanboys speculate on why I don’t write about their favorite product. The actual reason is usually that the company hasn’t released lenses that interest me (Nikon in 2017, for example) or I don’t have mounts to test them (Fuji and Pentax).

Micro 4/3 is a bit different. I can test most of them (the m4/3 mount we have can’t handle linear electromagnetic focusing lenses, but can handle all the others) but it requires taking time to set up the machine differently. Since most of our contract testing is for full-frame lenses, that makes it a little inconvenient to do m4/3, and because I’m old and grumpy, I tend to avoid inconvenience.

But now it’s the holidays, we don’t have any contract testing lined up, so I am going to test some of the more interesting m4/3 lenses. So now you m4/3 shooters are getting equal opportunity to read too-long articles full of charts and graphs just like everyone else. Like they say, “be careful what you ask for, you might get it.”

As we start looking at these, I want to emphasize a couple of things, because many m4/3 users will be new to this blog. First, we’re testing the lenses with no camera involved; all we’re evaluating is the optics. My interest is in the lenses, and the lenses only. Making lenses for a smaller imaging circle has some distinct theoretical advantages. Whether the lensmakers use those advantages for good and make better lenses, or for evil to cut corners and raise margins, well, that interests me quite a bit.

When you take a picture, you’re using the system (the camera and lens each add their limitations). Despite what many self-described experts say, it is very, very rare that just the lens or just the camera limit the output of the system. In practical terms, unless you have a really horrid lens, or a 4 megapixel camera, both camera and lens contribute to the final output. (If you have both a horrid lens and a 4 megapixel camera then you don’t need to be reading this.)

One other point: with m4/3 lenses you can’t make broad generalizations about the name on the outside, because that doesn’t necessarily reflect who made the components on the inside. So if the Olympus 25mm f/1.2 is pretty awesome (it is), for example, don’t take that to mean all Olympus lenses are pretty awesome (they aren’t). The name on the outside means “We paid the people who designed the lens, made the different components, and assembled it. Some of them actually work for us, some don’t, and the ones who did this lens didn’t necessarily do that other lens.”

Let’s Meet Today’s Players

We have several lenses that meet the criteria of being 25mm primes and being testable on our machine.

Notably missing from this list is the Panasonic 25mm f/1.7, because, as its Fanboys will probably tell you shortly, everyone knows it’s far better than all the others, and I wanted to keep that a secret. Or because it has an electromagnetic focusing motor and we can’t test it on the optical bench. Take whichever theory best suites your degree of paranoia.

I’ll also mention that while we usually test 10 copies of each lens, but when we get into m4/3 mounts, ten copies can be hard to come by. For that reason we’ve only tested five copies of the Voigtlander, that’s all we had in stock.

The Olympus 25mm f/1.2 ED Pro

We start with this lens because it’s considered an excellent new design that has been very popular. It’s by far the most expensive of this group at about $1,200. It contains multiple low dispersion and high refraction, as well as a single aspheric element. On the other hand, 19 elements make this a very complex lens, which made us wonder what copy-to-copy variation would be like.

Olympus Digital 25mm f/1.8

The other extreme is the little Olympus Digital 25mm. At $249 it’s the bargain lens of the bunch and it’s also the smallest. It doesn’t have as wide an aperture. It has two aspheric elements, but at this price range, we expect those are molded. So, we started with low expectations, but at this price, just a decent showing would make this a lens worth considering.

Panasonic Leica DG Summilux 25mm f/1.4 ASPH

At $600 this lens has a reasonable price, it’s not very large physically, has an f/1.4 aperture, and despite what I consider the stupidest hood design in all of photography history, has a fairly rabid following who love it. It has two aspheric elements and the simplest design of all the lenses we tested. Plus, it says Leica and Summilux on the front, and we all know what that means — they paid Leica to put ‘Leica’ and ‘Summilux’ on the front. In case I wasn’t clear, I went into this test a little cynical about this lens. It’s an older design, and I expected the newer design of the Olympus might have passed it by.

Voigtlander 25mm f/0.95 Nokton Type II

I maintain complete impartiality when it comes to lenses. Except I despise all things Voigtlander. Not because their lenses are bad, but because customer service is nonexistent and repairs nearly impossible to obtain, at least in the U. S. But at f/0.95 and a reasonable (for that kind of aperture) price tag of $800, this lens has to be considered for those who are willing to focus manually. Plus it has an all-metal construction which provides two advantages. First, it weighs a lot more. Second, you can describe it as ‘built like a tank’, which, of course, means ‘I don’t know anything about lens construction, but this one sure is heavy.’

OPTICAL TESTS

MTF Results

These results are all taken at widest aperture, so it’s not a direct comparison optically; a smaller aperture gives a better MTF. They’ll all improve stopped down a bit (more on that later). These MTFs are the average of 10 samples for all except the Voigtlander, which is the average of 5 samples.

Olympus 25mm f/1.2 ED Pro

This is actually very good for an f/1.2 lens, much better than the Canon 50mm f/1.2, for example. It maintains excellent sharpness in the center half of the image. It’s still quite sharp, although with some astigmatism, out to the edge.

Olympus Digital 25mm f/1.8

Here’s my first surprise of this testing batch. The little Olympus is really quite good. It falls off and has some astigmatism in the outer 1/3 of the image a bit, but not badly.

Panasonic Leica DG Summilux 25mm f/1.4 ASPH

The Panasonic was a bit disappointing. Even though it’s tested at a smaller aperture than the Olympus Pro, it doesn’t resolve nearly as well in the center. This is especially true of the higher frequencies (green, blue, and purple lines) which are critical for fine detail resolution on cameras with smaller pixels. It does maintain good resolution out to the edge of the frame, though.

Voigtlander 25mm f/0.95 Nokton Type II

This one was also better than I expected. It resolves decently in the center and falls off at the edges. But at f/0.95 that’s unavoidable. I was impressed that it could do this well. Lenses with apertures this wide are rarely this good. Right in the center, it resolves as well at f/0.95 as the Panasonic does at f/1.4.

Stop-Down Tests

We picked an average copy of the Voigtlander and Olympus 25mm f/1.2 to retest at f/1.4, to get a little more even comparison. (And used an average copy of the Panasonic for comparison, so we weren’t comparing single lenses to a group of lenses.)

Panasonic – Olympus

The Olympus was clearly better at higher frequencies (blue and purple lines). If you’re shooting with (or looking at a test done on) a 12-megapixel camera, the high frequencies are less important.

Voigtlander-Olympus

The Voigtlander surprises me yet again. It can match, perhaps slightly exceed, the Olympus in the center 1/2 of the image, although it can’t (like all ultra-wide aperture lens designs) keep up in the outer 1/3 of the image.

Olympus 25mm f1.8 and Olympus 25mm f/1.2 Pro at f/1.4

I didn’t test the Pro at f/1.8. To be honest, I didn’t think there would be enough competition that I’d be interested. So I’ll have to compare the Pro at f/1.4 to the Digital f/1.8 at f/1.8. Not really fair, since the Pro would do better at f/1.8. On the other hand, you can buy 4 of the little Digital f/1.8 for the price of one Pro, so … . .

It’s kind of shocking to me that the Digital f/1.8 is significantly sharper in the center. Things even up away from the center, but still, that’s impressive. Really. Impressive. Good job little-inexpensive-lens.

Comparisons at f/2.8

Because sometimes people stop down.

Olympus vs. Olympus

At f/2.8 the Pro is definitely superior in the outer 1/3 of the image, but the baby Olympus still impresses me with its performance at f/2.8.

Panasonic Leica vs. Olympus Pro

At f/2.8 there’s not a lot of difference between the two. The Olympus is a bit better at the edges of the image, but it’s a small difference.

Voigtlander vs. Olympus Pro

Not surprisingly, the Olympus is now a tiny better than the Voigt in the center, and far better in the outer half of the image.

Field Curvature (MTF vs. Field vs. Focus)

For those of you who don’t read our technical articles very often, the field curvature may be the most useful thing we give you. This is NOT distortion; rather it’s how the plane of best focus curves. The tangential and sagittal fields often curve differently; when they do you know, there will be astigmatism in those areas.

There’s other information you can get from field curvatures and if you’re interested here are some background articles: Fun with Fields of Focus 1, Fun with Fields of Focus II, Field Curvature and Stopping Down. I should mention these are done at f/5.6 because that gives a nice, clear picture of the field. Stopping down (or opening up) doesn’t change the curvature significantly. Keep in mind that when you’re shooting at a wider aperture, the field is much narrower.

We haven’t done these on many m4/3 lenses, so I had no idea what to expect. Because there’s less side-to-side distance to cover, it seemed likely that the field curvature would be less apparent.

Olympus 25mm f/1.2 ED Pro

There’s a gentle curve with this lens, but note that the sagittal field (right side) curves differently than the tangential field (left side). This means that while the overall field is flat, there is going to be some astigmatism off-center. The MTF graphs above reflect that.

Olympus Digital 25mm f/1.8

Here we see a more dramatic curve, but more of a tendency to be in the same direction. At wide apertures, though, the edges of the image are not going to be in focus at the same point that the center is. With this one, the field will truly curve. This also explains that the MTF curves above drop off at the edges, not because the lens is weaker, but because the field is curving away.

Panasonic Leica DG Summilux 25mm f/1.4 ASPH

Here we have two very different curves. The sagittal is almost perfectly flat; the tangential is in a W shape. This lens will have some mid-field astigmatism that will clear up near the edges, but will be pretty flat otherwise.

Voigtlander 25mm f/0.95 Nokton Type II

Here’s yet another surprise to me. I really expected the ultra-wide aperture lens would have severe field curvature, but it’s not too bad. There will be edge astigmatism (where the U-shaped tangential curve continues up, while the M-shaped sagittal curve turns down). There will be a slightly curved overall field.

Copy-to-Copy Variation

Micro 4/3 lenses, in general, have a lot of sample variation. Why this is I can’t say. What I can say is it’s not the fabled “QA check” that people imagine happens. Optical tolerance is done during the design of the lens and the assembly line, not by running a test at the end of manufacturing. Micro 4/3 lenses, as a rule, don’t have any compensating adjustable elements, so what you get at the end of the assembly line is what you get unless something is broken inside.

With these lenses, I wasn’t sure what to expect. The Olympus Pro is a complex lens; complexity and wide aperture tend to create a lot of variation. The Panasonic Leica and Olympus Digital f/1.8 are much simpler designs.

I’ve added the Variance Number to these graphs, although I want to point out that a number is a blunt tool; it’s not nearly as useful as looking at the graphs. As a rule, we consider prime lenses to be acceptable if the Variance number is less than 40, and random crap shoots if it’s over 80. So here are the graphs and variance numbers for the three lenses we could run them on. (We don’t consider five copies enough to comment on variance, so we skipped the Voigtlander in this part of the post.)

Olympus 25mm f/1.2 Pro

It looks better than the variance number suggests, but there’s some significant variation particularly in overall sharpness (notice how even in the center, there’s a fairly thick area).

Olympus 25mm Digital f/1.8

The variance number says it’s quite good, but the widening as you go away from center shows that there’s likely to be some difference in one side or the other on a given copy. The current variance number doesn’t take this into account as much as I would like it to.

Panasonic Leica Summilux f/1.4

Any way you look at it, there’s a lot of copy-to-copy variation, more in overall sharpness. This is getting close to the point where your copy and Bob’s copy are probably noticeably different.

So What Did We Learn Today?

Well, there are several good choices if you’re interested in a 25mm prime lens for your m4/3 camera. There’s not a bad choice in the bunch; I think most people would be happy with whichever one they have.

If you absolutely need an f/1.4 or wider aperture lens, the Olympus 25mm f/1.2 Pro is probably the best overall lens, although it comes at a hefty price. If you want the widest aperture possible and are willing to manually focus and realize you probably can’t get it repaired, the Voigtlander Nokton Type II is much better optically than I had expected.

The Pansonic Leica Summilux is a good lens, and at 2/3 the price of the Olympus Pro is a reasonable choice for a lot of people. It’s certainly not better, and the copy-to-copy variation makes me hesitant to recommend it very highly. On the other hand, as I said to start with, I’m a little cynical about that lens so maybe that’s affecting my judgment. It’s still a good lens at a reasonable price.

Me personally, though, I love a bargain, and in this case, I’d be willing to give up some aperture to get it. The little Olympus 25mm f/1.8 isn’t as wide an aperture as the others. Even stopped down, it’s not quite as sharp at the edges as either the Olympus Pro or the Panasonic Leica. But at that price and that small size, it’s a great bargain and a really good lens. This one surprised me in a very positive way.

Roger Cicala and Aaron Closz

Lensrentals.com

January, 2018

Note: It’s been a while since we did an m4/ test. For those of you m4/3 Fanboys and Detractors who are so vocal in some forums, this isn’t those forums. We welcome informed discussion and opinions. We do not allow snide, or ugly personal comments to other posters. I’m not a poster; you can be snide and ugly to me if you like.

190 Comments

Andre Yew · January 9, 2018
Roger and Aaron, thanks once again for an interesting and cool comparison! To your point that MTF is not the end-all-be-all of lens reviews, I would personally never use the Panasonic Leica 25/1.4 again. While it may be sharp, it has pretty large amounts of chromatic aberration especially wide open that make it unsuitable for me. I currently use the 25/1.7, but will keep my paranoid conspiracy theories to myself … for now. 🙂

I wish there was a way to derive CA performance information from the MTF, but Brandon tells me it can’t be done: the idea was that since you guys use multiple wavelengths of light to measure MTF, if you could derive MTF curves separately from the red, green, and blue components of the light, the separation of those curves should tell you about the CA performance since they won’t overlap with CA present.
1. Brandon Dube · January 9, 2018
  You would not want to take R, G, B components from a multispectral MTF measurement and call that something about CA. Monochromatic measures don’t give you chromatic performance! What you would instead want to do, as a first stab, is to measure the axial color (~=purple fringing), which we can do, and assign some of the loss of MTF to that instead of, say, spherical aberration or astigmatism.
  
  Off-axis you could do something similar for lateral color, but lateral color would take ages on our machine since we don’t have a motorized color filter wheel.
  
  There are complicated chromatic aberrations like spherochromatism and the chromatic variants of astigmatism and coma, it would take tremendous effort to reach an understanding of them from MTF, and in modern, high-complexity high performance lenses, they are probably as about as significant as any other aberration in limiting the final performance.
  1. Andre Yew · January 9, 2018
    Brandon, thanks for explaining in more detail. So if you measured the MTF separately for each wavelength, they would presumably be different. If so, what would those differences be caused by?
    1. Brandon Dube · January 9, 2018
      Imagine you have an RGB LED light source. You have a narrow blip in red, one in blue, and one in green. The thing in the image plane is the sum of the R + G + B images. If R, G, B are focused at different depths, you have at least two out of focus images added up. This is called axial color.
      
      If you measure MTF for R, G, B in isolation, you get the best focus MTF for each and axial color is completely removed. That doesn’t tell you about the performance for white light.
      
      Each would also be different because of the chromatic version of each monochromatic aberration. I.e. spherochromatism, a change in spherical aberration with color, would mean that blue could have a lot of spherical aberration, and green very little. Green would have closer to diffraction limited MTF than blue, and be a lot better.
      1. Andre Yew · January 10, 2018
        Right, that makes sense. What I’m wondering is if you collect full-spectrum PSFs (point-spread functions), and that’s an assumption I’m making since I don’t know how these optical bench MTF things actually work, why can’t you filter out individual frequencies from the full-spectrum PSFs (eg. bandpass the green part, for example) and compute individual MTFs for those bandpassed spectra? Or is it that you do actually collect R, G, and B in isolation? If so, then I see that you can’t do it.
        
        Brandon Dube · January 10, 2018
        We can do whatever spectral composition we want. White or photopic light are the best general options (white for, well, white things and photopic to to-some-extent duplicate the weight given to green by the bayer pattern).
        
        I do not know why we would want, a narrowband blue, green, or red spectra-associated MTF. Aside from color LEDs or lasers, I can’t think of many things in the world that have a small spectrum. Even highly saturated things like flowers for example have substantial spectral size. If you want to mimic the CFA of a camera, then those too have large spectral profiles.
        
        Andre Yew · January 10, 2018
        I was thinking that you’d focus and measure the white light, and then spectrally bandpass the results afterwards so that you could compare the MTFs for the individual spectra to see chromatic aberration.
        
        Brandon Dube · January 10, 2018
        That would be a very poor way of tackling the problem. The individual MTFs you get from that are only as meaningful as the scenes you can find that have spectra like that. There is no way to process out specific spectra after the capture. I’m also sick and need to rest, and don’t want to make an already long thread longer. Please email technicalsupport@olafoptical.com if you want to discuss more.
        
        Andre Yew · January 10, 2018
        No problem Brandon. I appreciate your time and responses as usual. Rest up and get better soon!
    2. Brandon Dube · January 9, 2018
      Imagine you have an RGB LED light source. You have a narrow blip in red, one in blue, and one in green. The thing in the image plane is the sum of the R + G + B images. If R, G, B are focused at different depths, you have at least two out of focus images added up. This is called axial color.
      If you measure MTF for R, G, B in isolation, you get the best focus MTF for each and axial color is completely removed. That doesn't tell you about the performance for white light.
      Each would also be different because of the chromatic version of each monochromatic aberration. I.e. spherochromatism, a change in spherical aberration with color, would mean that blue could have a lot of spherical aberration, and green very little. Green would have closer to diffraction limited MTF than blue, and be a lot better.
      1. Andre Yew · January 10, 2018
        Right, that makes sense. What I'm wondering is if you collect full-spectrum PSFs (point-spread functions), and that's an assumption I'm making since I don't know how these optical bench MTF things actually work, why can't you filter out individual frequencies from the full-spectrum PSFs (eg. bandpass the green part, for example) and compute individual MTFs for those bandpassed spectra? Or is it that you do actually collect R, G, and B in isolation? If so, then I see that you can't do it.
        Brandon Dube · January 10, 2018
        We can do whatever spectral composition we want. White or photopic light are the best general options (white for, well, white things and photopic to to-some-extent duplicate the weight given to green by the bayer pattern).
        I do not know why we would want, a narrowband blue, green, or red spectra-associated MTF. Aside from color LEDs or lasers, I can't think of many things in the world that have a small spectrum. Even highly saturated things like flowers for example have substantial spectral size. If you want to mimic the CFA of a camera, then those too have large spectral profiles.
        Andre Yew · January 10, 2018
        I was thinking that you'd focus and measure the white light, and then spectrally bandpass the results afterwards so that you could compare the MTFs for the individual spectra to see chromatic aberration.
        Brandon Dube · January 10, 2018
        That would be a very poor way of tackling the problem. The individual MTFs you get from that are only as meaningful as the scenes you can find that have spectra like that. There is no way to process out specific spectra after the capture. I'm also sick and need to rest, and don't want to make an already long thread longer. Please email technicalsupport@olafoptical.com if you want to discuss more.
Andre Yew · January 9, 2018
Roger and Aaron, thanks once again for an interesting and cool comparison! To your point that MTF is not the end-all-be-all of lens reviews, I would personally never use the Panasonic Leica 25/1.4 again. While it may be sharp, it has pretty large amounts of chromatic aberration especially wide open that make it unsuitable for me. I currently use the 25/1.7, but will keep my paranoid conspiracy theories to myself ... for now. :)
I wish there was a way to derive CA performance information from the MTF, but Brandon tells me it can't be done: the idea was that since you guys use multiple wavelengths of light to measure MTF, if you could derive MTF curves separately from the red, green, and blue components of the light, the separation of those curves should tell you about the CA performance since they won't overlap with CA present.
1. Brandon Dube · January 9, 2018
  You would not want to take R, G, B components from a multispectral MTF measurement and call that something about CA. Monochromatic measures don't give you chromatic performance! What you would instead want to do, as a first stab, is to measure the axial color (~=purple fringing), which we can do, and assign some of the loss of MTF to that instead of, say, spherical aberration or astigmatism.
  Off-axis you could do something similar for lateral color, but lateral color would take ages on our machine since we don't have a motorized color filter wheel.
  There are complicated chromatic aberrations like spherochromatism and the chromatic variants of astigmatism and coma, it would take tremendous effort to reach an understanding of them from MTF, and in modern, high-complexity high performance lenses, they are probably as about as significant as any other aberration in limiting the final performance.
Franck Mée · January 9, 2018
Hello Roger,
well, what I learnt today was that you don’t test Pentax because you don’t have the proper mount.
That comes as a surprise, since the K-mount basic specifications were public in the 80s, all except the most recent low-cost lenses have mechanical focusing rings so there would be no need for electrical focus control, and all except the most recent 55-300mm lens have a good old-fashioned mechanical linkage for the diaphragm.
So I would have thought it would have been the easiest mount to get working on an optical bench.

(Plus, as a Pentax user, I’d love to see how all the Ltd FA pancakes and some surprisingly un-vignetting DA lenses fare on a bench. I did ask Pentax; they politely but firmly refused to let met borrow all of them, and I don’t have the funds to buy ten copies of each. Plus I don’t have a bench.)

Anyway, it’s good to have an answer to a question I didn’t even know I was asking myself. Bravo !
1. Roger Cicala · January 9, 2018
  It’s simply a cost – benefit thing. A basic mount costs us about $800-$1,000. Additionally, some of the most interesting lenses are electromagnetic (linear focusing), so we would have to make an electronic mount. That about doubles the mount cost, and we have to buy a dedicated camera to use when testing them. Pentax and Fuji are more popular now than when we got the bench several years ago, but that’s a significant chunk of change for adding either. I will one of these days, but Olaf is a nonprofit (as in we don’t make any money, not as in we’re charitable), so not for a while.
  1. Franck Mée · January 13, 2018
    That makes sense. Thanks for the details!
Franck Mée · January 9, 2018
Hello Roger,
well, what I learnt today was that you don't test Pentax because you don't have the proper mount.
That comes as a surprise, since the K-mount basic specifications were public in the 80s, all except the most recent low-cost lenses have mechanical focusing rings so there would be no need for electrical focus control, and all except the most recent 55-300mm lens have a good old-fashioned mechanical linkage for the diaphragm.
So I would have thought it would have been the easiest mount to get working on an optical bench.
(Plus, as a Pentax user, I'd love to see how all the Ltd FA pancakes and some surprisingly un-vignetting DA lenses fare on a bench. I did ask Pentax; they politely but firmly refused to let met borrow all of them, and I don't have the funds to buy ten copies of each. Plus I don't have a bench.)
Anyway, it's good to have an answer to a question I didn't even know I was asking myself. Bravo !
1. Roger Cicala · January 9, 2018
  It's simply a cost - benefit thing. A basic mount costs us about $800-$1,000. Additionally, some of the most interesting lenses are electromagnetic (linear focusing), so we would have to make an electronic mount. That about doubles the mount cost, and we have to buy a dedicated camera to use when testing them. Pentax and Fuji are more popular now than when we got the bench several years ago, but that's a significant chunk of change for adding either. I will one of these days, but Olaf is a nonprofit (as in we don't make any money, not as in we're charitable), so not for a while.
Cary Talbot · January 9, 2018
Yay for MFT testing! Thanks for giving us MFT fans some nerdy goodness to devour. I’m certainly no lens expert but one thing that I’ve always liked about Oly lenses is that in my experience, even the lower end (cheaper) lenses seem to perform well – better than one might expect given their price, just as you found with the Digital f/1.8. Maybe it stems from the fact that Olympus is first and foremost a lens company (their bread & butter is microscopes). I don’t think they make much (if any) money off of their camera business. In some ways it seems like a bit of a hobby, in fact. But I’m sure glad they still enjoy making cameras and lenses for them.
Cary Talbot · January 9, 2018
Yay for MFT testing! Thanks for giving us MFT fans some nerdy goodness to devour. I'm certainly no lens expert but one thing that I've always liked about Oly lenses is that in my experience, even the lower end (cheaper) lenses seem to perform well - better than one might expect given their price, just as you found with the Digital f/1.8. Maybe it stems from the fact that Olympus is first and foremost a lens company (their bread & butter is microscopes). I don't think they make much (if any) money off of their camera business. In some ways it seems like a bit of a hobby, in fact. But I'm sure glad they still enjoy making cameras and lenses for them.
Claudia Muster · January 9, 2018
Meh. Considering this so-called f/1.2 is actually only a f/2.4 … (duck and run).
1. Roger Cicala · January 10, 2018
  LOL – Don’t you start, Claudia!!
2. Roger Cicala · January 10, 2018
  LOL - Don't you start, Claudia!!
3. hjwulff · January 10, 2018
  Seems to me it’s more like f/18. My Apo-Symmar 300 is also way faster at f/5.6. Puny little formats.
4. hjwulff · January 10, 2018
  Seems to me it's more like f/18. My Apo-Symmar 300 is also way faster at f/5.6. Puny little formats.
SpecialMan · January 10, 2018
Fantastic story. Thanks for mustering up the courage to venture into terra incognita….
You dropped an intriguing nugget there when you said “on a 12-megapixel camera, the high frequencies are less important.”
Could that be part of the reason that the just-released Panasonic GH5s has a 10.2 mp sensor? Will video look sharper with existing lenses when shot on a 10mp sensor vs. a 20mp sensor?
1. Brandon Dube · January 10, 2018
  I think the 10MP vs 20MP is more about low-light than lens resolution as far as the design of that camera goes. Bigger pixels can capture more photons (= improved DR) and also are less crowded (= less sources of noise), both of which improve high ISO performance.
  
  If the camera doesn’t use binning with the 20MP chip, opting for line skipping or a crop, the 10MP result should be superior in terms of sharpness. It is, at least, less demanding of the lens.
SpecialMan · January 10, 2018
Fantastic story. Thanks for mustering up the courage to venture into terra incognita....
You dropped an intriguing nugget there when you said "on a 12-megapixel camera, the high frequencies are less important."
Could that be part of the reason that the just-released Panasonic GH5s has a 10.2 mp sensor? Will video look sharper with existing lenses when shot on a 10mp sensor vs. a 20mp sensor?
1. Brandon Dube · January 10, 2018
  I think the 10MP vs 20MP is more about low-light than lens resolution as far as the design of that camera goes. Bigger pixels can capture more photons (= improved DR) and also are less crowded (= less sources of noise), both of which improve high ISO performance.
  If the camera doesn't use binning with the 20MP chip, opting for line skipping or a crop, the 10MP result should be superior in terms of sharpness. It is, at least, less demanding of the lens.
hjwulff · January 10, 2018
My thanks also for these tests. M4/3 is my most used system for versatile everyday shooting, and having or having used all of these lenses your tests back up my experience. When the Panasonic 25/1.4 came out, there wasn’t much else and the results on a 12mp body were quite good, but now the lens doesn’t impress that much anymore. Something you didn’t test also bothers me about the 25mm f1/4, and that is that the t-stop seems awfully close to that of the 25/1.7 Olympus, making the 25/1.4 even less interesting. I recently got the 25/1.2 Olympus and when I don’t mind the bulk, that lens gets the nod.
1. Roger Cicala · January 10, 2018
  We’re actually looking into evaluating actual T stop of lenses, but it’s way more complicated that I had expected. We may pull it off, but not certain yet.
  1. Speeding · January 10, 2018
    The only other (conveniently available) source for transmission data is DxO, but they employ an un-validated custom “rig” that yields varying T-stops depending on the camera it happens to be mounted on at the time. APS-C, for example, yields a higher T-stop than the same lens on FF. Hard to make heads or tails of the actual properties of the lens. They also say it is “ISO dependent” which is a head-scratcher.
    1. Brandon Dube · January 10, 2018
      Well, today we finished upgrading our spectral bench to handle big aperture lenses nicely, so that’s half the battle down. For the F/# part of T/#, we’re falling back to using image-based wavefront sensing to measure it, which is as complicated as it is sophisticated.
    2. Impulse_Vigil · January 16, 2018
      DxO’s T-stop measurements vary even on the same mount/format (e.g. E-M1 II w/25/1.2 vs other M4/3 bodies with the same lens)… I’ve read some theories on why but I’m still not totally sure it isn’t simply testing error.
hjwulff · January 10, 2018
My thanks also for these tests. M4/3 is my most used system for versatile everyday shooting, and having or having used all of these lenses your tests back up my experience. When the Panasonic 25/1.4 came out, there wasn't much else and the results on a 12mp body were quite good, but now the lens doesn't impress that much anymore. Something you didn't test also bothers me about the 25mm f1/4, and that is that the t-stop seems awfully close to that of the 25/1.7 Olympus, making the 25/1.4 even less interesting. I recently got the 25/1.2 Olympus and when I don't mind the bulk, that lens gets the nod.
1. Roger Cicala · January 10, 2018
  We're actually looking into evaluating actual T stop of lenses, but it's way more complicated that I had expected. We may pull it off, but not certain yet.
  1. Speeding · January 10, 2018
    The only other (conveniently available) source for transmission data is DxO, but they employ an un-validated custom "rig" that yields varying T-stops depending on the camera it happens to be mounted on at the time. APS-C, for example, yields a higher T-stop than the same lens on FF. Hard to make heads or tails of the actual properties of the lens. They also say it is "ISO dependent" which is a head-scratcher.
    1. Brandon Dube · January 10, 2018
      Well, today we finished upgrading our spectral bench to handle big aperture lenses nicely, so that's half the battle down. For the F/# part of T/#, we're falling back to using image-based wavefront sensing to measure it, which is as complicated as it is sophisticated.
    2. Impulse_Vigil · January 16, 2018
      DxO's T-stop measurements vary even on the same mount/format (e.g. E-M1 II w/25/1.2 vs other M4/3 bodies with the same lens)... I've read some theories on why but I'm still not totally sure it isn't simply testing error.
David Cockey · January 10, 2018
A question about interpreting MTF charts for lens intended for use with different size sensors. Roger commented “This is actually very good for an f/1.2 lens, much better than the Canon 50mm f/1.2, for example.” I assume that is based on comparing MTF curves for the same lp/mm. But should the Canon MTF curves be compared to m4/3 MTF curves of twice the numerical value to compensate for difference in sensor size and the corresponding different magnification required for the same display size? So the Olympus 40 lpmm MTF curve would be compared to the Canon 20 lpmm MTF curve?

If the Olympus 25mm f1.2 lens on a m4/3 camera and the Canon 50mm f1.2 lens on a “full frame” camera, both with say 20 megapixel sensors, are used to photograph the same scene and the resulting images were displayed at the same size, would there be an appreciable difference in apparent sharpness and if so which would be appear sharper?
1. Brandon Dube · January 10, 2018
  > But should the Canon MTF curves be compared to m4/3 MTF curves of twice
  the numerical value to compensate for difference in sensor size and the
  corresponding different magnification required for the same display
  size? So the Olympus 40 lpmm MTF curve would be compared to the Canon
  20 lpmm MTF curve?
  
  In short, yes. Olaf can tread water (read: kind-of-sort-of-break-even-and-buy-more-toys) because we’ve automated most of what we do to death. These M4/3 lenses are shown on our same 10..50 “FF scale” in part to keep shoving the data through the same pipeline as we undergo software upgrades, and in part to make some comparisons that should be forthcoming shortly enough.
  
  > If the Olympus 25mm f1.2 lens on a m4/3 camera and the Canon 50mm f1.2
  lens on a “full frame” camera, both with say 20 megapixel sensors, …
  
  The 25/1.2 is about as good as the Otus 55 at f/1.4, on an absolute scale. (reading fanboys note: it has to be twice as good on an absolute scale to be “as good”). It’s about 25% better than the 50/1.2L in the center, and smokes it in the corners. If you had asked if the Otus 55 or the Olympus 25 delivered the more apparently sharp image, it would be the otus no contest. Really that comparison would work with most any more recent 50 (Zony 55, Sony 50/1.4 FE, Sigma 50, tamron 45/1.8, etc). The 50L is older and worse. I would hazard that the 50L would look a little sharper, but wouldn’t want to be too committal about that.
  1. mohammad mehrzad · January 10, 2018
    One thing that seems to be missing from both your books is aperture equivalency.
    the pro has to be ” twice as good as the 50 L, to be as good”, when it is compared to the 50 L stopped down to f/2.4, to have the same DoF and same amount of total light hitting the sensor.
    (also ducks and runs..)
    1. Samuel H · January 10, 2018
      Yes, and you also have to raise the ISO of the big-sensor cameras to compensate for that, whenever you do sensor-level comparisons (noise, DR, etc).
      
      (I came down here to ask the lp/mm question, glad to have it nicely answered already; comparing the 40lp/mm lines here with the 20lp/mm lines on any FF lens MTF review, the result is clear: if you care a lot about sharpness you’ll want a bigger sensor)
      1. Carleton Foxx · January 15, 2018
        You’ve stumbled into the Sophie’s choice one faces when trying to compare two formats using equivalence. Do you compare them with all settings being the same, in which case larger formats always come out ahead? Or do you handicap the larger format by increasing ISO or stopping down to an “equivalent” aperture so the results are the same? I wish someone would come up with a definitive answer.
    2. Carleton Foxx · January 11, 2018
      Nothing is equivalent in this life. If you don’t believe me, ask your wife or life partner if s/he’d mind if you traded him/her for your next door neighbor’s wife or life partner. Everyone winds up with an equivalent spouse, everyone’s happy, right?
      1. mohammad mehrzad · January 16, 2018
        “hehe” is all I can say.
        I can actually use this argument the next time there is an equivalency war (not that uncommon these days) , to stop the madness.
        
        Tea Jay · March 20, 2018
        You also have to take into account the sizes and weights of the cameras and lenses… for physical training purposes of course FF wins. 🙂
David Cockey · January 10, 2018
A question about comparing MTF charts for lens intended for use with different size sensors. Roger commented "This is actually very good for an f/1.2 lens, much better than the Canon 50mm f/1.2, for example." I assume that is based on comparing MTF curves for the same lp/mm. But should the Canon MTF curves be compared to m4/3 MTF curves of twice the numerical value to compensate for difference in sensor size and the corresponding different magnification required for the same display size? So the Olympus 40 lpmm MTF curve would be compared to the Canon 20 lpmm MTF curve?
If the Olympus 25mm f1.2 lens on a m4/3 camera and the Canon 50mm f1.2 lens on a "full frame" camera, both with say 20 megapixel sensors, are used to photograph the same scene and the resulting images were displayed at the same size, would there be an appreciable difference in apparent sharpness and if so which would be appear sharper?
1. Brandon Dube · January 10, 2018
  > But should the Canon MTF curves be compared to m4/3 MTF curves of twice
  the numerical value to compensate for difference in sensor size and the
  corresponding different magnification required for the same display
  size? So the Olympus 40 lpmm MTF curve would be compared to the Canon
  20 lpmm MTF curve?
  In short, yes. Olaf can tread water (read: kind-of-sort-of-break-even-and-buy-more-toys) because we've automated most of what we do to death. These M4/3 lenses are shown on our same 10..50 "FF scale" in part to keep shoving the data through the same pipeline as we undergo software upgrades, and in part to make some comparisons that should be forthcoming shortly enough.
  > If the Olympus 25mm f1.2 lens on a m4/3 camera and the Canon 50mm f1.2
  lens on a "full frame" camera, both with say 20 megapixel sensors, ...
  The 25/1.2 is about as good as the Otus 55 at f/1.4, on an absolute scale. (reading fanboys note: it has to be twice as good on an absolute scale to be "as good"). It's about 25% better than the 50/1.2L in the center, and smokes it in the corners. If you had asked if the Otus 55 or the Olympus 25 delivered the more apparently sharp image, it would be the otus no contest. Really that comparison would work with most any more recent 50 (Zony 55, Sony 50/1.4 FE, Sigma 50, tamron 45/1.8, etc). The 50L is older and worse. I would hazard that the 50L would look a little sharper, but wouldn't want to be too committal about that.
  1. mohammad mehrzad · January 10, 2018
    One thing that seems to be missing from both your books is aperture equivalency.
    the pro has to be " twice as good as the 50 L, to be as good", when it is compared to the 50 L stopped down to f/2.4, to have the same DoF and same amount of total light hitting the sensor.
    (also ducks and runs..)
    1. Samuel H · January 10, 2018
      Yes, and you also have to raise the ISO of the big-sensor cameras to compensate for that, whenever you do sensor-level comparisons (noise, DR, etc).
      (I came down here to ask the lp/mm question, glad to have it nicely answered already; comparing the 40lp/mm lines here with the 20lp/mm lines on any FF lens MTF review, the result is clear: if you care a lot about sharpness you'll want a bigger sensor)
      1. Carleton Foxx · January 15, 2018
        You've stumbled into the Sophie's choice one faces when trying to compare two formats using equivalence. Do you compare them with all settings being the same, in which case larger formats always come out ahead? Or do you handicap the larger format by increasing ISO or stopping down to an "equivalent" aperture so the results are the same? I wish someone would come up with a definitive answer.
    2. Carleton Foxx · January 11, 2018
      Nothing is equivalent in this life. If you don't believe me, ask your wife or life partner if s/he'd mind if you traded him/her for your next door neighbor's wife or life partner. Everyone winds up with an equivalent spouse, everyone's happy, right?
      1. mohammad mehrzad · January 16, 2018
        "hehe" is all I can say.
        I can actually use this argument the next time there is an equivalency war (not that uncommon these days) , to stop the madness.
        Tea Jay · March 20, 2018
        You also have to take into account the sizes and weights of the cameras and lenses... for physical training purposes of course FF wins. :-)
DrJon · January 10, 2018
Presumably the actual m43 lens user will also be affected by the amount of distortion and how much some of the image is spread-out (and using what algorithm) by geometric correction inside the camera before they get to see the image. A lens with a lot of distortion will presumably fall away more (and even the centre will be scaled somewhat).

Interestingly DXO does distortion correction using their own measurements and I get a wider FoV with some lenses than using the “official” scaling. Also scaling may not fix all the error, e.g. the 12-35 has a lot of native distortion (5.8% at 12mm according to PhotoZone) but the “official” correction doesn’t correct all of it and leaves about 1.6%.

BTW I still don’t think I’d swap my 20mm f/1.7 mk I for any of these, I’m a bit sad that it didn’t get tested as I think it’s quite good (but understand it failed the “is it 25mm” test).
1. Roger Cicala · January 10, 2018
  DrJon, you’re totally correct about distortion. That’s why I didn’t include distortion numbers, the m4/3 cameras all correct it so the numbers we see through the lens don’t agree with what people see through the camera.
  1. DrJon · January 10, 2018
    Still maybe one day you could answer the age-old (err, -ish) question on whether you get a better result by designing a lens to optimise its cost/performance but need geometric distortion correction in-camera vs. lenses that do it optically? So is the software correction actually producing a better result for the same money, or just a better profit margin?
  2. Phillip Reeve · January 12, 2018
    I think the distortion numbers would be valuable to judge how much the sharpness of the final image will be affected by the forced distortion correction? That’s less of an issue for these normal lenses of which only the 1.4/25 forces distortion correction in most Raw converters but it will be more important with other M43 lenses which heavily rely on distortion correction. Oh and it would be interesting to know how much weaker or stronger distortion correction affects image sharpness. We have this older article from you but it only covers one lens at one focal length: https://www.lensrentals.com/blog/2013/01/you-can-correct-it-in-post-but/
DrJon · January 10, 2018
Presumably the actual m43 lens user will also be affected by the amount of distortion and how much some of the image is spread-out (and using what algorithm) by geometric correction inside the camera before they get to see the image. A lens with a lot of distortion will presumably fall away more (and even the centre will be scaled somewhat).
Interestingly DXO does distortion correction using their own measurements and I get a wider FoV with some lenses than using the "official" scaling. Also scaling may not fix all the error, e.g. the 12-35 has a lot of native distortion (5.8% at 12mm according to PhotoZone) but the "official" correction doesn't correct all of it and leaves about 1.6%.
BTW I still don't think I'd swap my 20mm f/1.7 mk I for any of these, I'm a bit sad that it didn't get tested as I think it's quite good (but understand it failed the "is it 25mm" test).
1. Roger Cicala · January 10, 2018
  DrJon, you're totally correct about distortion. That's why I didn't include distortion numbers, the m4/3 cameras all correct it so the numbers we see through the lens don't agree with what people see through the camera.
  1. Phillip Reeve · January 12, 2018
    I think the distortion numbers would be valuable to judge how much the sharpness of the final image will be affected by the forced distortion correction? That's less of an issue for these normal lenses of which only the 1.4/25 forces distortion correction in most Raw converters but it will be more important with other M43 lenses which heavily rely on distortion correction. Oh and it would be interesting to know how much weaker or stronger distortion correction affects image sharpness. We have this older article from you but it only covers one lens at one focal length: https://www.lensrentals.com...
Kachadurian · January 10, 2018
I’m with you on the Pan-Leica hood. What were they thinking?
Kachadurian · January 10, 2018
I'm with you on the Pan-Leica hood. What were they thinking?
KG · January 10, 2018
When trying to be a smart-arse, at least spell check so you don’t look even dumber: “Take whichever theory best suites your degree of paranoia.” I doubt the 25 1.7 has “fanboys” – what it does have is a lot of interested people who are looking to get into the M43 system on the cheap. Leaving it out looks you look a smug elitist fanny.
1. Roger Cicala · January 10, 2018
  When correcting others spelling and grammar, perhaps you should avoid phrases like “looks you look”.
  1. KG · January 10, 2018
    That’s not a phrase, it’s a weird phone correction, and I’m not the one writing a supposed serious article. So you’re still a fanny. Also correct grammar would be “correcting other people’s grammar” – double fail.
    1. Pak T · January 10, 2018
      Someone needs to lighten up. Jeez. You come across as a fanny orifice. Looking at your profile I see your interest is striving to be that.
    2. Dave · March 20, 2018
      Wow John, you need to chill out.
      1. KG · March 21, 2018
        Who the f#*k is John? Also, get f#cked, this article is a joke, the guy is an old decrepit elitist f#cktard.
        
        Dave · March 22, 2018
        I hope you have had the chance to take your meds John. It’s not good for people to see you so upset like this. Should we schedule you another appointment with Dr Fitzpatrick? It really helped last time, at least for a few weeks. You really should stay away from social media when your serotonin is so low.
2. Paul · January 10, 2018
  Crikey – a guy goes out of way to use his expensive optical bench to spread light on the performance of some lenses that don’t often get evaluated in such detail, and all you can do is point out some minor spelling/grammar mistake! What value does your comment bring to the world compared to Roger’s efforts?
KG · January 10, 2018
When trying to be a smart-arse, at least spell check so you don't look even dumber: "Take whichever theory best suites your degree of paranoia." I doubt the 25 1.7 has "fanboys" - what it does have is a lot of interested people who are looking to get into the M43 system on the cheap. Leaving it out looks you look a smug elitist fanny.
1. Roger Cicala · January 10, 2018
  When correcting others spelling and grammar, perhaps you should avoid phrases like "looks you look".
  1. KG · January 10, 2018
    That's not a phrase, it's a weird phone correction, and I'm not the one writing a supposed serious article. So you're still a fanny. Also correct grammar would be "correcting other people's grammar" - double fail.
    1. Pak T · January 10, 2018
      Someone needs to lighten up. Jeez. You come across as a fanny orifice. Looking at your profile I see your interest is striving to be exactly that.
2. Paul · January 10, 2018
  Crikey - a guy goes out of way to use his expensive optical bench to spread light on the performance of some lenses that don't often get evaluated in such detail, and all you can do is point out a minor spelling/grammar mistake! What value does your comment bring to the world compared to Roger's efforts?
  From me Roger - a big "thank you!!"
umad?! · January 10, 2018
If I had the kind of money I’d sent you a six figure sum, to test the Fuji medium format lenses. Would be interesting to see.

Great work you are doing, thumbs up!
umad?! · January 10, 2018
If I had the kind of money I'd sent you a six figure sum, to test the Fuji medium format lenses. Would be interesting to see.
Great work you are doing, thumbs up!
Speeding · January 10, 2018
Roger,
Thank you for putting time and effort into this. I enjoyed the read and bookmarked it for future reference.
Speeding · January 10, 2018
Roger,
Thank you for putting time and effort into this. I enjoyed the read and bookmarked it for future reference.
Claudia Muster · January 10, 2018
I don’t understand the part of the “linear electromagnetic focusing lenses”. What is “linear electromagnetic focusing” and why can’t you handle it?
1. Roger Cicala · January 10, 2018
  Claudia, see: https://www.lensrentals.com/blog/2016/04/a-look-at-electromagnetic-focusing/
  Basically the focusing element travels up and down a rail on an electromagnetic. If there’s no power applied, it slides back to the bottom. So we have to have an electronic mount to hold the focusing element in position. We have this for the Sony bench because most FE lenses use that system. With Fuji and m4/3 only some lenses use that, many use standard focusing motors.
  1. Claudia Muster · January 10, 2018
    Thanks. So basically an ordinary linear motor. But how do those other lenses which you could test move the focusing element? I guess their drives are also somehow linear. Piezoelectrically?
    1. Roger Cicala · January 10, 2018
      The others are a mixture of piezo, ring USM, etc. but all have a focusing element that remains in the last position it is placed in when the electronics is removed; those can be set to infinity focus and then tested. The linear motors, when there’s no electricity, just fall back to the bottom by gravity. You can generally tell by turning the lens upside down and right side up — you’ll hear the focusing group slide back and forth.
      1. Shawn Wright · January 10, 2018
        That explains the rattle my 25/1.7 had. Could it also explain some of the focus issues reported with this lens, especially on Olympus bodies, or would that just be wild speculation? I’m speaking of reports of front or back focus, which really shouldn’t happen with CDAF as I understand it. Do any Olympus lenses use linear electromagnetic focus?
        
        Roger Cicala · January 11, 2018
        There are a few that do, but I can’t think of which ones off hand. I don’t have any evidence that it’s more or less accurate than other methods.
      2. Claudia Muster · January 10, 2018
        I see. Thanks.
    2. Roger Cicala · January 10, 2018
      The others are a mixture of piezo, ring USM, etc. but all have a focusing element that remains in the last position it is placed in when the electronics is removed; those can be set to infinity focus and then tested. The linear motors, when there's no electricity, just fall back to the bottom by gravity. You can generally tell by turning the lens upside down and right side up -- you'll hear the focusing group slide back and forth.
      1. Shawn Wright · January 10, 2018
        That explains the rattle my 25/1.7 had. Could it also explain some of the focus issues reported with this lens, especially on Olympus bodies, or would that just be wild speculation? I'm speaking of reports of front or back focus, which really shouldn't happen with CDAF as I understand it. Do any Olympus lenses use linear electromagnetic focus?
        Roger Cicala · January 11, 2018
        There are a few that do, but I can't think of which ones off hand. I don't have any evidence that it's more or less accurate than other methods.
Claudia Muster · January 10, 2018
I don't understand the part of the "linear electromagnetic focusing lenses". What is "linear electromagnetic focusing" and why can't you handle it?
1. Roger Cicala · January 10, 2018
  Claudia, see: https://www.lensrentals.com...
  Basically the focusing element travels up and down a rail on an electromagnetic. If there's no power applied, it slides back to the bottom. So we have to have an electronic mount to hold the focusing element in position. We have this for the Sony bench because most FE lenses use that system. With Fuji and m4/3 only some lenses use that, many use standard focusing motors.
Caerolle · January 10, 2018
Great to see some results for mFT, thanks Roger! 🙂

Funny, I have used the Olympus 25/1.8, and own the Panny 25/1.4, which I like better, though not totally based on optical quality. I love the 50mm angle-of-view, and the 25/1.4 is one of my fave lenses, warts and all (clicking aperture, CA, obviously soft at 1.4, HORRID hood).

I hopefully have at least a decent copy, as I got it used from LensRentals; in fact, I buy all my lenses that way. My rationale is that while the used lenses from here cost about as much as a new lens from a dealer, I don’t have to worry about getting a bad one, or even testing for decentering and all that. I figure LR tests them and fixes or replaces the worst, so I don’t have to deal with convincing a dealer that I have a bad one or whatever, just makes life simpler, which is how I like it, lol.

Thanks again, Roger!

Carol 🙂
Caerolle · January 10, 2018
Great to see some results for mFT, thanks Roger! :)
Funny, I have used the Olympus 25/1.8, and own the Panny 25/1.4, which I like better, though not totally based on optical quality. I love the 50mm angle-of-view, and the 25/1.4 is one of my fave lenses, warts and all (clicking aperture, CA, obviously soft at 1.4, HORRID hood).
I hopefully have at least a decent copy, as I got it used from LensRentals; in fact, I buy all my lenses that way. My rationale is that while the used lenses from here cost about as much as a new lens from a dealer, I don't have to worry about getting a bad one, or even testing for decentering and all that. I figure LR tests them and fixes or replaces the worst, so I don't have to deal with convincing a dealer that I have a bad one or whatever, just makes life simpler, which is how I like it, lol.
Thanks again, Roger!
Carol :)
offtheback · January 11, 2018
Always fun+informative to read your pieces Roger.Thanks for being the reasoned voice in this crazy photo world.
Gov · January 11, 2018
I think every lensreview should consist of a sample of 5, may be 10 copies. It is pretty useless if a lens has such sample variation that in reallife a lens could be either much better or much worse due to sample variation. I love the very objective way this is tested and the authors honestly about his prejudice towards one or two of the lenses, which he then explains and I have to say I agree with his reasoning here too. No customer service to speak of? That is pretty bad. A big thank you!
Phillip Reeve · January 11, 2018
Question to Brandon: How can it be that the OM 1.2/25 is so much less sharp than the FE 1.8/55 (in relative terms comparing 10 LP/mm (FE55) to 20 LP/mm (OM25) and 20 LP/mm to 40 LP/mm) at their widest aperture? The OM should have all the advantages: It is massively more complex (19 vs 10 elements), more expensive, heavier and it has a smaller aperture. Yet the Sony has a much higher contrast in that comparison .

Thanks 🙂
1. Brandon Dube · January 11, 2018
  Better and easier optical design — f/1.8 is a lot easier than f/1.2, but the olympus lens also has a very complicated design. The light is squeezed down towards the middle (elements 1-5), pushed back up (6-8), slowly made to be converging again (9-15), and finally focused (16-19). This is the technique used by photolithography lenses to flatten the field (get rid of field curvature and astigmatism). The requirements of those lenses are sub-nanometer field flatness, so they really need it. For a camera lens? Well, not even the Masterprimes or Summilux-C lenses do that (at $40,000/ea). You can see Olympus leveraged it here to produce a very flat field, pretty high resolution (in absolute terms…) design at the expense of making the lens very complicated and expensive to produce.
  
  The Sony lens also has 3 aspheres (maybe 4 aspheric surfaces) vs 1 in the olympus. If they had opted for 3-4 aspheres and 6 fewer lenses in Olympus’ design, without this field curvature correcting technique, they probably could have produced a superior design.
  
  So I would say that the Sony lens, whoever designed it, was done more cleverly and the result is better. The Olympus lens, whoever designed it, is probably a good optical designer (the product is pretty good and utilizes some advanced design techniques) but didn’t stop to ask ask “should I” before betting on “can I.”
  
  As an aside, the A7rIII has 4.5 micron pixels and can “see” up to 110 lp/mm. None of the spatial frequencies shown on these plots really show “pixel level” detail. We show down to more like 2-4 pixel level of detail, which is probably about how close you want to look at your pictures unless you’re posting 100% crops online or using them to measure things.
  1. Phillip Reeve · January 11, 2018
    Thanks for your analysis 🙂
    
    I wouldn’t have thought that it is harder to design a f/1.2 lens for a smaller format than a f/1.8 lens for a sensor with twice the diagonal.
    1. Brandon Dube · January 12, 2018
      The field of view (~40 degrees for a “normal” lens) and F/# set the difficulty. Same field of view, quite a lot bigger aperture, harder design.
      1. Phillip Reeve · January 12, 2018
        But a f/1.2 aperture for M43 is quite a bit smaller than a f/1.8 for FF?
        
        Brandon Dube · January 12, 2018
        Why does the diameter of the lens matter? Aberrations work in normalized coordinate systems.
  2. SpecialMan · January 11, 2018
    Hey! Don’t hate on we 100 percenters. I shoot a lot of people of a certain age who appreciate it when I diminish the look of their wrinkles. For me it’s easier to make my work undetectable when I am at least 100 percent. Sometimes I have to go to 800 to get
  3. Someone · January 18, 2018
    Some fast zooms do something similar. See for example Sigma 18-35/1.8: https://www.sigma-global.com/common/lenses/cas/product/art/a_18_35_18/specifications/images/construction.gif
    1. Brandon Dube · January 18, 2018
      The path of light through that is not very similar to Olympus’ lens.
2. Claudia Muster · January 11, 2018
  It might be a deliberate design decision. Olympus designed the 1.2 lens for an extra smooth bokeh (their buzzword for it is “feathered bokeh”). They achieve this by not fully correcting the spherical aberration. Which inevitably diminishes the peak sharpness. At least that’s what Olympus themselves say on their site: http://asia.olympus-imaging.com/product/dslr/mlens/f12pro/
  1. Barbu Mateescu · January 29, 2018
    „It’s a feature, not a bug.”
    Yeah right.
Phillip Reeve · January 11, 2018
Question to Brandon: How can it be that the OM 1.2/25 is so much less sharp than the FE 1.8/55 (in relative terms comparing 10 LP/mm (FE55) to 20 LP/mm (OM25) and 20 LP/mm to 40 LP/mm) at their widest aperture? The OM should have all the advantages: It is massively more complex (19 with lots of fancy glass vs 10 elements), more expensive, heavier and it has a smaller aperture. Yet the Sony has a much higher contrast in that comparison .
Thanks :)
1. Brandon Dube · January 11, 2018
  Better and easier optical design -- f/1.8 is a lot easier than f/1.2, but the olympus lens also has a very complicated design. The light is squeezed down towards the middle (elements 1-5), pushed back up (6-8), slowly made to be converging again (9-15), and finally focused (16-19). This is the technique used by photolithography lenses to flatten the field (get rid of field curvature and astigmatism). The requirements of those lenses are sub-nanometer field flatness, so they really need it. For a camera lens? Well, not even the Masterprimes or Summilux-C lenses do that (at $40,000/ea). You can see Olympus leveraged it here to produce a very flat field, pretty high resolution (in absolute terms...) design at the expense of making the lens very complicated and expensive to produce.
  The Sony lens also has 3 aspheres (maybe 4 aspheric surfaces) vs 1 in the olympus. If they had opted for 3-4 aspheres and 6 fewer lenses in Olympus' design, without this field curvature correcting technique, they probably could have produced a superior design.
  So I would say that the Sony lens, whoever designed it, was done more cleverly and the result is better. The Olympus lens, whoever designed it, is probably a good optical designer (the product is pretty good and utilizes some advanced design techniques) but didn't stop to ask ask "should I" before betting on "can I."
  As an aside, the A7rIII has 4.5 micron pixels and can "see" up to 110 lp/mm. None of the spatial frequencies shown on these plots really show "pixel level" detail. We show down to more like 2-4 pixel level of detail, which is probably about how close you want to look at your pictures unless you're posting 100% crops online or using them to measure things.
  1. Phillip Reeve · January 11, 2018
    Thanks for your analysis :)
    I wouldn't have thought that it is harder to design a f/1.2 lens for a smaller format than a f/1.8 lens for a sensor with twice the diagonal.
    1. Brandon Dube · January 12, 2018
      The field of view (~40 degrees for a "normal" lens) and F/# set the difficulty. Same field of view, quite a lot bigger aperture, harder design.
  2. SpecialMan · January 11, 2018
    Hey! Don't hate on we 100 percenters. I shoot a lot of people of a certain age who appreciate it when I diminish the look of their wrinkles. For me it's easier to make my work undetectable when I magnify the pictures to at least 100 percent. For the very elderly—people in Roger's age bracket—I often magnify to 400 and even 800 percent.
  3. Someone · January 18, 2018
    Some fast zooms do something similar. See for example Sigma 18-35/1.8: https://www.sigma-global.co...
    1. Brandon Dube · January 18, 2018
      The path of light through that is not very similar to Olympus' lens.
2. Claudia Muster · January 11, 2018
  It might be a deliberate design decision. Olympus designed the 1.2 lens for an extra smooth bokeh (their buzzword for it is "feathered bokeh"). They achieve this by not fully correcting the spherical aberration. Which inevitably diminishes the peak sharpness. At least that's what Olympus themselves say on their site: http://asia.olympus-imaging...
  1. Barbu Mateescu · January 29, 2018
    „It's a feature, not a bug.”
    Yeah right.
Phillip Reeve · January 11, 2018
Regarding Cosina Voigtlander lenses in general: Do you see a general trend in regard to variance and do at least some have compensating elements?
1. Roger Cicala · January 11, 2018
  I’ve seen some centering elements in them, but no other adjustments. At least some are simple stacks (element, spacer, element, etc.) with no compensations at all.
2. Roger Cicala · January 11, 2018
  I've seen some centering elements in them, but no other adjustments. At least some are simple stacks (element, spacer, element, etc.) with no compensations at all.
James Murray · January 11, 2018
Please help me understand V, the variance number. Can I compare the V in this post with the values in your blog post “Measuring Lens Variance”?

Also, is sensor size a factor in how we should interpret V? That is, should we “hope” that m43 lenses show half the variance that is tolerable in FF because when considering prints of the same size we are magnifying the m43 image more? Or is that already part of your calculation?
1. Roger Cicala · January 11, 2018
  The V calculation is rather a blunt tool. TMI – the number looks at the slope of Monte Carlo statistical analysis of the lenses at several positions. It weights difference between copies heavier than difference within a copy.
  
  To your more specific questions: Should it be half of FF? No, because it’s weighted to difference between copy sharpness. Should it be a little less? Yes because it’s not measuring as far off axis.
  
  The graphics are much more informative than the number, it lets you know if center sharpness is varying or off axis, or both. But I understand it doesn’t have a number and we all love a single number.
2. Brandon Dube · January 12, 2018
  Some more specifics:
  
  > Can I compare the V in this post with the values in your blog post “Measuring Lens Variance”
  
  Please do not. Very different formulas, completely incomparable numbers.
  
  There are no normalizations or reference image sizes in the formula. Metrics that have those tend to smell funny.
JAHM · January 11, 2018
Please help me understand V, the variance number. Can I compare the V in this post with the values in your blog post "Measuring Lens Variance"?
Also, is sensor size a factor in how we should interpret V? That is, should we "hope" that m43 lenses show half the variance that is tolerable in FF because when considering prints of the same size we are magnifying the m43 image more? Or is that already part of your calculation?
1. Roger Cicala · January 11, 2018
  The V calculation is rather a blunt tool. TMI - the number looks at the slope of Monte Carlo statistical analysis of the lenses at several positions. It weights difference between copies heavier than difference within a copy.
  To your more specific questions: Should it be half of FF? No, because it's weighted to difference between copy sharpness. Should it be a little less? Yes because it's not measuring as far off axis.
  The graphics are much more informative than the number, it lets you know if center sharpness is varying or off axis, or both. But I understand it doesn't have a number and we all love a single number.
2. Brandon Dube · January 12, 2018
  Some more specifics:
  > Can I compare the V in this post with the values in your blog post "Measuring Lens Variance"
  Please do not. Very different formulas, completely incomparable numbers.
  There are no normalizations or reference image sizes in the formula. Metrics that have those tend to smell funny.
lunic · January 12, 2018
Thank you for this great review. It is very interesting that the Leica DG 25/1.4 shows better curve than the M.ZD 25/1.8 @F2.8. According to this review, now I’m safe to say that 25/1.4 is better than 25/1.8 when stopped down. But it seems that you used 25/1.7’s construction diagram. the right one for 25/1.4 is: http://www.letsgodigital.org/images/artikelen/25/summilux-25mm.jpg
And one question – what means the ‘molded’ aspherical lens on M.ZD 25/1.8?
1. Roger Cicala · January 12, 2018
  Thank you, lunic. First, I’m assuming a molded aspheric, I don’t know it is for sure.
  
  A ground polished aspheric is milled from optical glass like the other elements. These are generally considered the highest quality and usually what is found in lenses like Canon L, Leica, Zeiss, etc.
  
  A molded aspheric softened glass is pressed into an aspheric mold and allowed to cool. This is less expensive. It’s supposed to, with recent technology, be nearly as good, but nobody will say exactly what nearly is.
  
  The least expensive is a hybrid aspheric where a plastic molded aspheric piece is glued to a glass piece. These are of lower quality.
lunic · January 12, 2018
Thank you for this great review. It is very interesting that the Leica DG 25/1.4 shows better curve than the M.ZD 25/1.8 @F2.8. According to this review, now I'm safe to say that 25/1.4 is better than 25/1.8 when stopped down. But it seems that you used 25/1.7's construction diagram. the right one for 25/1.4 is: http://www.letsgodigital.or...
And one question - what means the 'molded' aspherical lens on M.ZD 25/1.8?
1. Roger Cicala · January 12, 2018
  Thank you, lunic. First, I'm assuming a molded aspheric, I don't know it is for sure.
  A ground polished aspheric is milled from optical glass like the other elements. These are generally considered the highest quality and usually what is found in lenses like Canon L, Leica, Zeiss, etc.
  A molded aspheric softened glass is pressed into an aspheric mold and allowed to cool. This is less expensive. It's supposed to, with recent technology, be nearly as good, but nobody will say exactly what nearly is.
  The least expensive is a hybrid aspheric where a plastic molded aspheric piece is glued to a glass piece. These are of lower quality.
David Bateman · January 12, 2018
Wow this great, thank you for starting to test M43rds lenses. I was surprised not to see requests for lenses below in the comments, but I bet soon people will want all of them tested and compared.
Since I own the Panasonic 25mm f1.4, I will agree that the hood is crazy. But glad to see it hold well to the newer Olympus 25mm f1.2. At what feels like half the size, weight and cost, it looks good.
The other complicated issue with M43rds lenses is 2 companies doing things a little different. My Panasonic GM5 does not transmit any under 410nm light to the sensor. So all UV is lost in the filter on the sensor. Olympus on the other hand, I find only about a stop less uv transmitted, then a full spectrum converted camera. So I suspect Panasonic designs lenses knowing the narrower light transmission and has different in camera corrections than Olympus. Thus the purple blobs people find in Olympus cameras with Panasonic lenses and other CA issues. This may also play out in your lens tests, or not.
Sad to see so much variation in the lenses, but interesting to see that its easily possible to a have a weak Olympus 25mm and a strong Panasonic 25mm, which would explain some side to side single len reviews, were the Panasonic tested better.
Thank you for starting testing. I look forward to more tests when you have the chance.
David Bateman · January 12, 2018
Wow this great, thank you for starting to test M43rds lenses. I was surprised not to see requests for lenses below in the comments, but I bet soon people will want all of them tested and compared.
Since I own the Panasonic 25mm f1.4, I will agree that the hood is crazy. But glad to see it hold well to the newer Olympus 25mm f1.2. At what feels like half the size, weight and cost, it looks good.
The other complicated issue with M43rds lenses is 2 companies doing things a little different. My Panasonic GM5 does not transmit any under 410nm light to the sensor. So all UV is lost in the filter on the sensor. Olympus on the other hand, I find only about a stop less uv transmitted, then a full spectrum converted camera. So I suspect Panasonic designs lenses knowing the narrower light transmission and has different in camera corrections than Olympus. Thus the purple blobs people find in Olympus cameras with Panasonic lenses and other CA issues. This may also play out in your lens tests, or not.
Sad to see so much variation in the lenses, but interesting to see that its easily possible to a have a weak Olympus 25mm and a strong Panasonic 25mm, which would explain some side to side single len reviews, were the Panasonic tested better.
Thank you for starting testing. I look forward to more tests when you have the chance.
Hal Knowles · January 13, 2018
Roger, Aaron, et al. Thanks for another incredible blog post and testing run! AS a Micro Four Thirds (m43) user, I am excited to see you finally testing lenses for the system. In the future, should you have the optical bench set up for additional m43 lenses, I would love to kindly request that you consider testing and adding the SLR Magic 25mm t0.95 Hyperprime Cine III. It is a lens you carry in stock and some reviews suggest it may outperform the Voigtlander 25mm (at least some copies a f some apertures).

https://www.lensrentals.com/rent/slr-magic-25mm-t.95-hyperprime-cine-for-micro-4-3

Thanks!
Hal

P.S. While sharpness is certainly a critical feature of all lenses, for some situations other lens characteristics may take precedence. For example, I am fortunate to have a nicely centefed and very sharp copy of the Panasonic Leica 25mm f1.4 lens. However, I often find that in environmental portraiture (which is presumably a major use of thu lens and its focal length), I am consistently underwhelmed with the point light source bokeh balls. At all apertures, they have pretty horrible onion ring abberations and at the f1.4 and f1.6 aperture in the image edges they take on a very unattractive truncated shape that I find highly visually distracting. It’s a shame because I find the other aspects of it’s bokeh (outside of the distinct balls) to be quite nice (e.g. front/rear blur smoothness and transitions). It is so close to being a near perfect lens for my needs in that focal range, but I find myself preferring the performance and portability of the Panasonic 20mm f1.7 over it and I am considering replacing the Panasonic Leica 25mm f1.4 with the aforementioned SLR Magic 25mm t0.95 for its more pleasing bokeh and wider aperture, despite its presumed considerable drop off in sharpness.

Out of curiosity, has the Lens Rentals Blog ever written any posts about the various lens characteristics and abberations and how lens designers and manufacturers balance their correction (or lack of correction) for desired aesthetic and performance
Lo-Wok Li Ya · January 14, 2018
Thanks, Roger and Brandon! A true joy to read.
What I find strange is that many lenses (OM 1.8, Pana Leica, Voigt) exibit the increase of astigmatism when stopped down. How is that possible since we know that astigmatism decreases at lower apertues?!
1. Brandon Dube · January 14, 2018
  Astigmatism and field curvature are invariant with aperture. They are reduced in apparent magnitude when the aperture is closed, because the depth of field is increased. If a lens has focus shift from spherical aberration, the plane selected in the MTFvFvF plots may move to one that is more astigmatic (e.g. if the T and S fields move away at the edge, which is what astigmatism is).
  
  The separation of the T and S lines in an MTF vs Field plot is not directly indicative of astigmatism; there can be several causes for that (astigmatism being one of them.)
  1. Lo-Wok Li Ya · January 17, 2018
    Thank you so much! You are great and supportive!
Lo-Wok Li Ya · January 14, 2018
Thanks, Roger and Brandon! A true joy to read.
What I find strange is that many lenses (OM 1.8, Pana Leica, Voigt) exibit the increase of astigmatism when stopped down. How is that possible since we know that astigmatism decreases at lower apertues?!
1. Brandon Dube · January 14, 2018
  Astigmatism and field curvature are invariant with aperture. They are reduced in apparent magnitude when the aperture is closed, because the depth of field is increased. If a lens has focus shift from spherical aberration, the plane selected in the MTFvFvF plots may move to one that is more astigmatic (e.g. if the T and S fields move away at the edge, which is what astigmatism is).
  The separation of the T and S lines in an MTF vs Field plot is not directly indicative of astigmatism; there can be several causes for that (astigmatism being one of them.)
zapatista · January 15, 2018
When are you gonna review some Canon stuffz?!? It’s not fair, all this panolympusjunk.
1. Roger Cicala · January 15, 2018
  Made my day!!!!!! 🙂
zapatista · January 15, 2018
When are you gonna review some Canon stuffz?!? It's not fair, all this panolympusjunk.
1. Roger Cicala · January 15, 2018
  Made my day!!!!!! :-)
Maya · January 15, 2018
Thanks for the article ! Now I guess that I know why I never managed to find a 25mm f1.8 which wasn’t badly misaligned. My own real-life experience with this lens is in line with the article.
Maya · January 15, 2018
Thanks for the article ! Now I guess that I know why I never managed to find a 25mm f1.8 which wasn't badly misaligned. My own real-life experience with this lens is in line with the article.
James Whitehouse · January 16, 2018
Thank you, I really find these tests useful and informative. Is there any chance you could include CA, though, as a lot of times sharpness is only one factor of interest for me, and I often find CA bugs me even with quite expensive lenses.
nuitamericaine · January 16, 2018
Thank you, I really find these tests useful and informative. Is there any chance you could include CA, though, as a lot of times sharpness is only one factor of interest for me, and I often find CA bugs me even with quite expensive lenses.
Impulse_Vigil · January 16, 2018
Thanks for this! Any and all M4/3 tests from your are most welcome IMO.
Hal Knowles · January 16, 2018
Thanks Roger et al., for the awesome Micro Four Thirds lens camparison! Should you ever have the optical bench set up for future Micro Four Thirds lens testing, I’d like to kindly request if you could add the SLR Magic 25mm t0.95 Hyperprime to this existing 25mm comparison. It is a lens you carry and though it is a bit more niche than the others, some of the few reviews available suggest that it may be sharper than the Voigtlander 25mm lens.

https://www.lensrentals.com/rent/slr-magic-25mm-t.95-hyperprime-cine-for-micro-4-3

Thanks!
Hal
Hal Knowles · January 16, 2018
Thanks Roger et al., for the awesome Micro Four Thirds lens camparison! Should you ever have the optical bench set up for future Micro Four Thirds lens testing, I'd like to kindly request if you could add the SLR Magic 25mm t0.95 Hyperprime to this existing 25mm comparison. It is a lens you carry and though it is a bit more niche than the others, some of the few reviews available suggest that it may be sharper than the Voigtlander 25mm lens.
https://www.lensrentals.com...
Thanks!
Hal
Ivar Brekke · January 16, 2018
Thank you for your test, find your tests very interesting, please bring up more m43 stuff! Resolution is an important parameter on any lens, and as you say in that regard the Olympus 25mm f1.8 is really good for the price. However, I have been looking up many picture comparisons with the PL 25 and I must say that it is a really good performer in color “pop” which is hard to test. If you look at this comparison you might see what I mean:
http://www.daisukiphoto.com/2014/08/olympus-vs-panasonic-25mm-bokeh-field.html

I find the PL to have more color dynamic range, while the olympus are more grayish/flatter. Look at the red and green in the first comparison (or the colors in all of the comparisons). Also the highlights are lighter and the shadows darker, giving it a nicer look in my perception. I have seen the same on all other comparisons around the web, still very few reviewers even mentions it. Here is another comparson with the voightlander included:
https://www.youtube.com/watch?v=Vd7WwfWuuMw

The difference is noticeable, I think it shows in all PL lenses in comparison with simialr focal length olympus ones. Panasonic have managed to create a consistent look in their PL lens range, which is why I think the users love the lens range (me included). The old 12-35 which I also own, does not have the same PL character, which is why I do not use it as much and should probably have sold it a long time ago.

I wish reviewers around the web had better tools/methology to better compare these kind of differences (color and bokeh) when comparing lenses.
1. Brandon Dube · January 16, 2018
  Color is forthcoming from us 🙂
  1. Ivar Brekke · January 17, 2018
    That would be great! Bokeh would also be interesting, It might be a little hard to define the rules of what good bokeh is. Leica thinks that bokeh should have a contrast “falloff”, whichs than make the in focus object pop more for example. Some reviews I have seen thinks that good bokeh is circular bokeh balls, which is a silly parameter, as cateye bokeh for example svirls more, which might be what you are after.
    1. Brandon Dube · January 17, 2018
      I doubt we will ever take a stab at bokeh, it’s too subjective.
2. Daniel Guryca · January 16, 2018
  I agree. I did some side by side comparisons between my 2 lenses Oly 17mm 1.8 and Pana 15mm 1.7 and there is definitely a difference. All ‘Leica’ lenses seem to delivery more contrasty images. So out of camera jpegs do have a bit richer colors. I would even say that they somehow look more 3Dish whatever it is.
  1. Ivar Brekke · January 17, 2018
    The PL15 is my favorite M43 lens 🙂
Ivar Brekke · January 16, 2018
Thank you for your test, find your tests very interesting, please bring up more m43 stuff! Resolution is an important parameter on any lens, and as you say in that regard the Olympus 25mm f1.8 is really good for the price. However, I have been looking up many picture comparisons with the PL 25 and I must say that it is a really good performer in color "pop" which is hard to test. If you look at this comparison you might see what I mean:
http://www.daisukiphoto.com...
I find the PL to have more color dynamic range, while the olympus are more grayish/flatter. Look at the red and green in the first comparison (or the colors in all of the comparisons). Also the highlights are lighter and the shadows darker, giving it a nicer look in my perception. I have seen the same on all other comparisons around the web, still very few reviewers even mentions it. Here is another comparson with the voightlander included:
https://www.youtube.com/wat...
The difference is noticeable, I think it shows in all PL lenses in comparison with similar focal length Olympus ones. Panasonic have managed to create a consistent look in their PL lens range, which is why I think the users love the lens range (me included). The old 12-35 which I also own, does not have the same PL character, which is why I do not use it as much and should probably have sold it a long time ago.
I wish reviewers around the web had better tools/methology to better compare these kind of differences (color and bokeh) when comparing lenses.
1. Brandon Dube · January 16, 2018
  Color is forthcoming from us :)
  1. Ivar Brekke · January 17, 2018
    That would be great! Bokeh would also be interesting, It might be a little hard to define the rules of what good bokeh is. Leica thinks that bokeh should have a contrast "falloff", which then make the in focus object pop more for example.
    1. Brandon Dube · January 17, 2018
      I doubt we will ever take a stab at bokeh, it's too subjective.
2. Daniel Guryca · January 16, 2018
  I agree. I did some side by side comparisons between my 2 lenses Oly 17mm 1.8 and Pana 15mm 1.7 and there is definitely a difference. All 'Leica' lenses seem to delivery more contrasty images. So out of camera jpegs do have a bit richer colors. I would even say that they somehow look more 3Dish whatever it is.
  1. Ivar Brekke · January 17, 2018
    The PL15 is my favorite M43 lens :)
Claudia Muster · January 16, 2018
Ok, now that everybody seems to place their wishes what µ4/3 lenses should be tested, I’ll add mine: I think it would be interesting to see and compare the MTF curves and their variation of the Oly 300 and the Panaleica 200, both with and without the 1.4 converter. Even when their price tag is certainly out of the range for most amateur photographers.
Claudia Muster · January 16, 2018
Ok, now that everybody seems to place their wishes what µ4/3 lenses should be tested, I'll add mine: I think it would be interesting to see and compare the MTF curves and their variation of the Oly 300mm f/4 and the Panaleica 200mm f/2.8, both with and without the 1.4 converter. Even when their price tag is certainly out of the range for most amateur photographers.
Jonas Palm · January 17, 2018
Thanks a lot for these tests!
I particularly appreciate that you stopped down for comparisons – I very rarely shoot at full opening.
Jonas Palm · January 17, 2018
Thanks a lot for these tests!
I particularly appreciate that you stopped down for comparisons - I very rarely shoot at full opening.
Meier Kurt · January 17, 2018
Hallo Roger,
Thanks for leaving your comfort-zone and thanks for your time.
I really enjoyed reading.
But: There are many more m43-Lenses out there:
So please stay grumpy but don’t get really old
(you are not) before you had them all.

(ohhhhhhh…come on; at least 200 f/2.8 vs. 300 f/4 and….)

Thank you for sharing.

May the (m43)-Light always be with you
Meier Kurt · January 17, 2018
Hallo Roger,
Thanks for leaving your comfort-zone and thanks for your time.
I really enjoyed reading.
But: There are many more m43-Lenses out there:
So please stay grumpy but don't get really old
(you are not) before you had them all.
(ohhhhhhh...come on; at least 200 f/2.8 vs. 300 f/4 and....)
Thank you for sharing.
May the (m43)-Light always be with you
John Gaylord · January 28, 2018
There are also some interesting old Four Thirds lenses that might be considered, including the amazing Oly 14-35mm f/2 and the Panny 25mm D Summilux f/1.4. I know: legacy, one is not a prime, but still excellent and available. AFAIK there are no MTF comparison tests between FT and MFT lenses, which I would find useful because I wonder if the newer models are ‘that much’ better (or not).
Roger Cicala · January 30, 2018
For several who have asked — I have one current MTF project to write up, another to finish testing and write up, then we’ll be back to doing some more m4/3 testing. In other words, in February hopefully, but not in early February.
1. Devil's Advocate · February 13, 2018
  Is there anything the m43 community can help you with like lending you lenses to make an article viable?
  1. Roger Cicala · February 14, 2018
    Not really. I usually have access to enough copies, although I sometimes have to wait for copies to rotate through stock to get enough samples. The 40mmish primes are being done now and should be written up next week.
Roger Cicala · January 30, 2018
For several who have asked -- I have one current MTF project to write up, another to finish testing and write up, then we'll be back to doing some more m4/3 testing. In other words, in February hopefully, but not in early February.
Thinkinginpictures · February 13, 2018
Well that sucks…and I just bought the Voigtlander 65mm F2. I guess I’ll have to live on the wild side and hope it doesn’t go bad on me. It’s a brilliant lens. Perhaps the best lens I’ve ever owned.
1. Roger Cicala · February 14, 2018
  They really are excellent and unique lenses. They just don’t have the infrastructure to support timely repairs. On the other hand, it often takes 4 to 6 months to get a Leica repaired, so maybe they’re just emulating Leica.
  1. Thinkinginpictures · February 14, 2018
    Thanks for the perspective!
Thinkinginpictures · February 13, 2018
Well that sucks...and I just bought the Voigtlander 65mm F2. I guess I'll have to live on the wild side and hope it doesn't go bad on me. My heart sunk a bit when I read that...I just started acquiring a lot of Voigtlander lenses for FE. It's a brilliant lens. Perhaps the best lens I've ever owned. Don't let me down Voigt!
1. Roger Cicala · February 14, 2018
  They really are excellent and unique lenses. They just don't have the infrastructure to support timely repairs. On the other hand, it often takes 4 to 6 months to get a Leica repaired, so maybe they're just emulating Leica.
Zak McKracken · July 29, 2018
Hmmm… am I the only one who whould have liked to see BIF MTF graphs? I’m guessing that you already have the required data from the field curvature measurements.

Especially the Voigtländer lens might look a lot better in that comparison, but probably the f/1.8, too.
Zak McKracken · July 29, 2018
Hmmm... am I the only one who whould have liked to see BIF MTF graphs? I'm guessing that you already have the required data from the field curvature measurements.
Especially the Voigtländer lens might look a lot better in that comparison, but probably the f/1.8, too.
William L · October 12, 2018
Thanks – you might have saved me a considerable amount of money! I’ve been looking for a ‘nifty fifty’ M4/3 lens to play with, and though I could write the 1.2 PRO lens off as a business expense, it would be hard to justify at the end of the day. I typically shoot either with wide-angle lenses, or telephoto lenses.
Vilhjalmr E. · October 12, 2018
Thanks - you might have saved me a considerable amount of money! I've been looking for a 'nifty fifty' M4/3 lens to play with, and though I could write the 1.2 PRO lens off as a business expense, it would be hard to justify at the end of the day. I typically shoot either with wide-angle lenses, or telephoto lenses. So the Oly 25mm f1.8 looks like a great, fun lens with decent quality.
Joseph Schachner · December 19, 2018
I must have a “good” copy of the 25mm f/1.4 because I think it’s great. I have not seen chromatic aberation (maybe I’m just blind to it?). I use it for indoor photography a lot, and even though it’s an “old” lens it works just fine on a G9.
Joseph Schachner · December 19, 2018
I must have a "good" copy of the 25mm f/1.4 because I think it's great. I have not seen chromatic aberation (maybe I'm just blind to it?). I use it for indoor photography a lot, and even though it's an "old" lens it works just fine on a G9.
Dave Haynie · February 20, 2019
Nice review… but it doesn’t help my resistance against the lure of the M.Zuiko 25mm f/1.2 PRO. I have the f/1.8 version, and it’s a great performer, no complaints. I also have a Mitakon Zhongyi 25mm f/0.95… that would have been an interesting one to toss into the mix. In my experience, not as sharp as the 25mm f/1.8 when you go wide aperture, but given the price, that’s the main competition. And it’s not always about maximizing sharpness, and it looks stellar and gestalt-appropriate on the Pen F.
Dave Haynie · February 20, 2019
Nice review... but it doesn't help my resistance against the lure of the M.Zuiko 25mm f/1.2 PRO. I have the f/1.8 version, and it's a great performer, no complaints. I also have a Mitakon Zhongyi 25mm f/0.95... that would have been an interesting one to toss into the mix. In my experience, not as sharp as the 25mm f/1.8 when you go wide aperture, but given the price, that's the main competition. And it's not always about maximizing sharpness, and it looks stellar and gestalt-appropriate on the Pen F.
Wayne Leary · October 6, 2019
I see this was a while ago but is still quite relevant. Good work I enjoyed reading it.
J Mareeswaran · November 3, 2019
Great review

Finally, Some m4/3 MTF Testing: 25mm Prime Lens Comparison

Let’s Meet Today’s Players

The Olympus 25mm f/1.2 ED Pro

OPTICAL TESTS

MTF Results

Stop-Down Tests

Panasonic – Olympus

Voigtlander-Olympus

Olympus 25mm f1.8 and Olympus 25mm f/1.2 Pro at f/1.4

Comparisons at f/2.8

Field Curvature (MTF vs. Field vs. Focus)

Copy-to-Copy Variation

So What Did We Learn Today?

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