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Lenses and Optics

Sony E Mount Lens Optical Bench Tests

Published October 20, 2015

It has taken a long time, the sacrifice of a couple of cameras and lenses, and a lot of soldering, but we have finally managed to rig up a powered Sony mount to our optical bench so that we can test the new full-frame Sony and Sony-Zeiss E-mount lenses.

For those of you who haven’t understood why there has been a problem, I’ll explain it for you. The optical bench tests lenses at infinity focus. Most lenses have a mechanical focusing ring. You set it to infinity, confirm it (because some lenses can actually focus past infinity, which screws up the test results), put them on the bench and test them. A few lenses are ‘focus-by-wire’; they are focused by the electric AF motor even when you turn the focusing ring manually. Most of these are no trouble either. You put them on the camera, focus to infinity, take them off and the focus stays where it last was.

Sony’s newer lenses (and some micro 4/3 lenses) are different. They are focused by an electromagnet. You can put them on the camera and focus to infinity, but when you take them off the camera the focusing group just falls back to wherever it wants to be, which is never infinity focus.

So in order to test Sony lenses on the optical bench we had to find a way to keep the lens hooked to the camera, but at the same time have it off the camera because it has to be mounted to the bench’s Sony test plate. Our solution isn’t particularly elegant, but it works. We took apart a random lens and camera to get a lens mount and camera mount. We modified one of the Optical Bench mounting plates so it contained a Sony camera mount. We then wired that to an empty lens mount. We place the test lens in the mounting plate (red line), put the empty lens mount into the camera, and we can control the lens focus by using the camera while the lens is on the optical bench.

 

Yeah, it looks crude. But this is version 3.0; the first two attempts were much cruder. Before you make fun remember we sacrificed an A7, an 18-200 lens, and a $900 optical test plate just to get you some numbers. OK, we really did it because it sounded fun and because nobody else in the Known Universe can test Sony lenses on an optical bench right now and we can. So there!

Remember This is Beta Testing

The goal and objective is to compare Sony lenses both to each other and to other E-mount lenses from Zeiss, Sigma, and whomever. But I know people are also going to compare them to Canon, Nikon, and other lenses. I want to emphasize that we’re learning as we go and I’m writing as we learn. So two months from now I may be writing one of those articles that tell you we’ve found an error in our technique or a better way to do it. I don’t think so, we’ve been experimenting for a while now, but that’s what happens when you do new things that nobody else is doing.

More importantly, there are some differences in the testing methods for the Sony-mount lenses compared to the Canon and Nikon mount tests we’ve been doing. We want to be as transparent as possible, so I’m going to identify all of those differences I can think of.

There is Glass in the Path

First, unlike most of the Canon and Nikon mount tests we’ve already done, we’ve added 2mm of optical glass to the testing path of these lenses. Why? Because we ran lots of trial tests and found that at least the first Sony lenses we tested performed much better with that amount of glass in the optical path. It made a big difference with the Sony lenses, while it did not make much difference for most of the Canon and Nikon lenses we tested. Why are Sony lenses more sensitive? My best guess, and it’s just a guess, is that their exit pupil is further to the rear than some of the other lenses. It’s also very possible that the shorter flange-to-sensor distance (18mm for Sony, 44mm for Canon) makes the lenses more sensitive to glass in the optical pathway. (For both of you who want to know we tested both 3 and 1mm and 2mm gave the best results.)

We ‘See’ Fewer Corners

With all of our other lenses the optical bench gives us a complete open circle. We test 4 quadrants and see results out to the edge of the frame (20mm of sensor distance) in all 4 directions. Our electronic Sony mount includes the rectangular light baffle that the Sony camera mount has. This means at certain rotations (top to bottom in camera terms) our view is cut off at roughly 15mm, the distance of the top or bottom of the sensor from the center. The result is our numbers for a Canon or Nikon lens measure each lens all the way to 8 edges (2 edges for each of 4 rotations). With the Sony lenses we only measure 6, the top and bottom are cut off. You can make an argument that this might make the variation appear slightly larger (there are few numbers in the mathematically average), or slightly smaller (we might not ‘see’ a bad corner) than it would be if we could measure all 4 corners. I think the only important point is that we should be conservative when making comparisons to Canon and Nikon tests. The tests are slightly different.

There May Be a Bigger Difference Between These Tests and Pictures You Take

We know that Sony ‘cooks the RAW’ at least a bit, doing some in-camera modifications to raw files. I don’t know exactly what or to what degree. They aren’t alone in this, it seems to be the wave of the future to do some in-camera correction for at least distortion. But it appears they are the only full-frame cameras to do in-camera RAW correction at this moment.

What that means, though, is that tests of just the lens without a camera body, like we’re doing here, may be quite a bit different than what comes out of the camera. For example, our tests of the FE 35mm f/1.4 ZA show a LOT more distortion than tests done on a camera body using Imatest or DxO optics; we show 4% distortion where most of the on-camera testing shows 1% or less. This probably means that the camera is processing the distortion out of the image. (It could also mean that the distortion is very different focused up close, where DxO and Imatest work, then at infinity, where the optical bench works.) Depending upon your point of view that may be good, bad, or make no difference to you at all.

The same thing may (or may not) apply to sharpening. If there’s a little sharpening going on in the raw image, then you may think “Roger you said that lens isn’t so sharp, but the RAW images look very sharp, and the report from this other site using Imatest says it’s very sharp, too”.  To take it a step further, sharpening may be applied more to the corners and edges, or vignetting correction applied, or other stuff. (Again, I don’t know if it is or not.)

Because so many people struggle with this idea, I’ll repeat what I say over and over: I’m testing the lens alone. (You would not believe how many people ask what camera these tests are done on.) Other sites are testing the image that has been processed by the camera. Since you’re using the camera, their results will look more like your results and you’ll not see much of the distortion in your images. About 90% of you are going to think ‘why would I care’, and you’d be right. What comes out of the camera is more important.

But if you’re a lens geek like me, what the lens is actually providing TO the sensor is important, if only for esoteric reasons. Or maybe not just esoteric reasons. If the lens is inferior, but the image looks better from in-camera processing, you may not be able to manipulate the RAW as much as you would like, because it’s already been manipulated once. A lot of people are very excited about Sony uncompressed raw because they will be able to do more intense post-processing. But uncompressed doesn’t mean unmodified. If the raw is still modified before you get it, post-processing may still be somewhat limited.

Of course, the vast majority of photographers could care less, but then they probably don’t read this blog 🙂

Some Test Results

We have lots of Sony and Sony mount lenses to test and it’s going to take a while to get them all done. Today I’ll present 3 of the lenses many people have wanted to see: the Sony FE 35mm f/1.4 ZA, the Sony FE 55mm f/1.8 ZA, and the Sony FE 90mm f/2.8 Macro OSS. We’ll show you the MTF curves and copy-to-copy variation graphs for each, comparing them to some of the Canon and Nikon mount lenses we’ve tested. Again, please remember that testing techniques are slightly different for the Sony lenses as explained above.

Sony FE 35mm f/.4 ZA

(Note: this post originally published too early with an incorrect MTF graph for the Sony FE 35mm f/1.4 ZA lens. It has been corrected as of 4:20 pm CST. I apologize for the error, I was trying to get the post up as I was leaving for New York.)

We’ll compare the Sony to several other 35mm lenses. The Sigma and Canon are amazingly good 35mm lenses. The Sony is better than the more average Nikon 35mm f/1.4.  It’s certainly not quite as good as either the Canon or the Sigma as far as resolution goes.

 

Roger Cicala and Aaron Closz, Olaf Optical Testing, 2015

 

When we look at copy-to-copy variation, something we’ve long thought was the case becomes documented.

Roger Cicala and Aaron Closz, Olaf Optical Testing, 2015

 

I’m going to avoid comparing the consistency numbers, because as we’ve mentioned the testing for the Sony lenses is a bit different. But the variation graphs show what our photographic experience with this lens has suggested. The FE 35mm f/1.4 ZA lenses are all over the place. It actually is a bit worse than the graphs look because a lot of the variance is WITHIN a copy, not just copy-to-copy. None of the 10 copies we tested had even corners. And I’ll editorialize and say that none of the dozens we’ve tested on Imatest had even corners either. If you use this lens for centered objects, you’ll be happy. If you want 4 sharp corners, it’s not likely to happen unless your standards for equal sharpness are pretty low.

Sony FE 55mm f/1.8 ZA

Going into these tests, I had expected the 55mm f/1.8 ZA to do better than the 35mm f/1.4 and it did. Compared to a sampling of other 50-something lenses, the Sony 55 does very well on the MTF charts. Its center resolution is superb and it maintains sharpness very well to the edges. The Nikkor 58mm and Zeiss Otus 55m lenses are being tested here at f/1.4, which gives the Sony lens a bit of an unfair advantage, but it’s still excellent and holding it’s own against the best lenses in this range at the very least.

 

Roger Cicala and Aaron Closz, Olaf Optical Testing, 2015

 

The copy-to-copy variation graphs for the 55mm lens show it has a lot better consistency than the 35mm, too. There’s some variation, but it’s similar to most of the other 50ish lenses we’ve tested. The Canon 50mm f/1.8 is very much the exception, being the only 50mm lens we’ve tested that has almost no copy-to-copy variation.

Roger Cicala and Aaron Closz, Olaf Optical Testing, 2015

 

Sony FE 90mm f/2.8 OSS Macro

The FE 90mm Macro shows a good, not great MTF chart. It’s certainly not bad, but not something to get overly excited about. Remember, though, that Macro lenses often perform better close up, where they are designed to work, than at infinity focus, where this test is done. If you’re using this as a long portrait or short telephoto lens, these results should reflect what you see (other than if there’s sharpening done in RAW). At macro distances, it may perform differently.

 

Roger Cicala and Aaron Closz, Olaf Optical Testing, 2015

Things aren’t quite so good when we look at copy-to-copy variation, though. Medium focal length macro lenses are usually very consistent. In this case, the Sony has a lot of variation compared to the others. The type of variation we’re seeing is also quite different from the Sony FE 35mm f/1.4. That lens has a lot of corner variation in every copy, but the center remains is consistently sharp comparing one lens to another. With the Macro, there’s a lot of center variation and it’s not particularly worse in the corners. This suggests there is significant copy-to-copy variation in overall sharpness, rather than individual lenses have a bad corner.

 

Roger Cicala and Aaron Closz, Olaf Optical Testing, 2015

 

So What Can We Take Away Today?

Mostly we are just starting with FE lens testing. Over the next few weeks, we should get a good handle on how the Sony lenses compare to each other.

I think there’s no question we’ve seen support for what a lot of people are claiming: the 35mm f/1.4 ZA lens is very likely to have some tilt with one corner or side out of the plane of focus. Depending on what you photograph this may make no difference to you, or may be a huge issue. But I doubt sending copy after copy back is going to make much difference (you may trade a soft right upper corner for a slightly soft left side, etc.). We’ve taken a couple of these apart and there’s not a ton of optical adjustments that can be made: there are a set of shims behind the front group that can be modified a bit, but it’s a crude and very time-consuming adjustment, so I don’t think it’s generally going to be something that can be fixed.

The 55mm f/1.8 is really a good lens, very sharp and consistently made. The 90 mm f/2.8 is a decent lens, reasonably sharp, but there seems to be a fair bit of copy-to-copy variation in overall sharpness.

All that being said, these lenses may look better on-camera than on the optical bench because there seems to be at least some modification of files as the raw is written. We’ll get a better handle on that as we test more lenses. And let me emphasize, the only clear evidence we see for that is with distortion correction. There may be nothing more than that going on.

 

Roger Cicala and Aaron Closz

Lensrentals.com

October, 2015

Author: Roger Cicala

I’m Roger and I am the founder of Lensrentals.com. Hailed as one of the optic nerds here, I enjoy shooting collimated light through 30X microscope objectives in my spare time. When I do take real pictures I like using something different: a Medium format, or Pentax K1, or a Sony RX1R.

Posted in Lenses and Optics
  • Roger Cicala

    Scott, good points, thank you. We carry all of those lenses but testing m4/3 just has been on the back burner most of the time. We’re getting their, though.

  • DtEW

    I don’t know what you’re smoking, Aaron… but your assertions about the DXOMark results for SEL35F14Z vs. the Sigma 35mm f/1.4 Art are easily disproven by a simple visit to that site. Be sure to choose a sensor with the same resolution, i.e. the Sony A7R vs. Nikon D810 that tn1krr linked in his response to you.

    I would suggest studying the “Sharpness” tab, with data presented in the “Profiles” format for easy, superimposed comparison.

    In fact, you’ve done an excellent job of drawing attention to the fact that in the wide-open state, the SEL35F14Z is in an entirely lower league relative to the Sigma 35mm f/1.4 Art.

  • Charlie Webster

    Roger, you are our hero. I’m really looking forward to copy variations on M lenses, both Leica and Zeiss. Someday. But just to be clear, in testing any old M lens, say a 50 cron v4, you would not put glass in the path, right? This would not improve performance for any lens designed for film, correct?

  • scott kirkpatrick

    Leica has stated on a few occasions that only vignetting and color shift corrections are done on the raw file. These only change the pixel intensities at specific points, without shifting image information from one pixel to another. Olympus doesn’t say what is done for the raw file, but when I use CaptureOne to develop OM-D raw files, I see a whole list of lens profiles, generally involving only distortion correction. The tool presents a choice of correcting to the manufacturer-specified 100% or less, if you choose, but it doesn’t say what percentage amount of correction is being applied. To estimate that, you simply slide the distortion correction back to zero and eyeball the result. I can be surprisingly large. For example, the 12-40/2.8 PRO lens from Olympus has significant barrel distortion at the wide end (12 to 14 mm) but little visible distortion at 18 mm and above. The 7-14/2.8 is really distorted at 7 (I’d guess nearly 10%) but sliding the CaptureOne generic correction to 80% neutralizes it. That lens has no COne profile at the moment. Applying distortion correction at this point is not as harmful, since the image can be shifted after the demosaicing of the Bayer filter information is all done, and each pixel has RGB values.

    Does LensRental carry M43 lenses such as the PRO series of zooms, the 85/1.8 and the PanaLeica 25/1.4 or some of the 1.2 and 0.95’s? Would love to see what their native, uncorrected qualities are.

    scott

  • Roger Cicala

    Charlie, we know the glass has a major effect on wide aperture lenses with a short exit pupil (complex optical formula thing – not a physical measurement). Rangefinder and most legacy lenses benefit from removal of glass because they were designed for film with no glass in the path. Digital lenses are generally designed for glass in the path, because there will always be cover glass. The Kolari modification makes the camera much better with the classic film lenses that have short exit pupil distances.

  • Roger Cicala

    Charlie, we will. First step is to get a wide-open database, then we’ll go back and do stop downs. I have all the new Zeiss and the Nikon 24-70 f/2.8 VR to do this week, we’ll get back to Sony next week.

  • Charlie Webster

    Regarding the “glass in the path”

    “My best guess, and it’s just a guess, is that their exit pupil is further to the rear than some of the other lenses. It’s also very possible that the shorter flange-to-sensor distance (18mm for Sony, 44mm for Canon) makes the lenses more sensitive to glass in the optical pathway.”

    This does not make sense to me (which admitedly is not the perfect meter). Do you put glass in the Path of a 50 APO Leica? Any Rangefinder lens? Are not the issues you mention the same with M240?

    I suspect it must be the cover many of us have had Kolari remove. For me, this mod has made a large difference in performance with many legacy lenses, not just RF wides on original A7.

    Charlie

  • Charlie Webster

    I hope in future you will add f/4 and f/5.6 on these lenses. Some of use do shoot landscapes 😉

    TY so much for all your contributions to our knowledge, Roger.

  • Andrew

    Excellent review and looking forward for the rest of the FE mount lens. Thanks!

  • tn1krr

    Aaron,

    dxomark most certainly has not found Sony 35/1.4 to be sharper than Sigma Art 35/1.4. To my eye when both lenses are put in front of a same 36 MP AA-less sensor the result match Roger’s findings. Nor is the FE 90/2.8 sharpest lens they have tested, it is the sharpest FE lens they have tested. Have a look at yourself, Sigma 35 on D810 vs Sony 35 on A7R. Measurements->Sharpness->Profiles under the link below, Sigma is way sharper on open apertures and Sony does not catch it even stopping down.

    http://www.dxomark.com/Lenses/Compare/Side-by-side/Sony-FE-Carl-Zeiss-Distagon-T-STAR-35mm-F14-ZA-on-Sony-A7R-versus-Sigma-35mm-F14-DG-HSM-A-Nikon-on-Nikon-D810__1518_917_1057_963

    My 90/2.8 Macro is very very good at close distances, but at infinity my Batis 85/1.8 is noticeably better.

  • Roger Cicala

    Aaron, my results are often very different from DxO. We’re testing entirely different things and different aspects of the lens. If you understand optics and the testing involved, it gives people the opportunity to see more than one aspect of the lens. For people into that, reading and comparing what all the sites say is important; there’s a ton of good information. If you want to simply go with “73.4 rating means it is a better lens than this one with a 68.6 rating” then you should find single site you like and go with what they say.

    With all respect, though, I’ve spent years not only looking at what the other testers are getting, but doing those tests (both Imatest and DxO). I moved on to a more expensive method of testing (the optical bench) because of the limitations I found in that testing. If you look around, you’ll find I’ve also tested the 90mm on Imatest, so I’m aware.

    As I say on my site dozens of times, I’m not a lens reviewer. I’m an investigator. People like reading along with my investigations so I publish them. If a lot of people don’t read what I write very thoroughly and jump to conclusions, there’s not much I can do about it.

  • Brandon

    David,

    The data is gathered with a Trioptics ImageMaster, not OLAF. OLAF is essentially a reversed MTF bench, but the MTF cannot be measured using OLAF as some parameters necessary to MTF calculation are not measured (e.g. magnification).

    Concerns over the image circle are certainly valid, but keep that hard vignetting you mentioned in mind. If the lenses were measured out to 22mm and based on the loose centering of the bayonet relative to the optical axis you find that corners vignette, or worse you measure the point where it transitions into vignetting, this is going to grossly skew the average and variance data.

    While “as built” performance, especially with these loosely assembled/toleranced lenses is very far from the nominal performance, we do generally see the variance of pretty much *every* lens be more or less smooth, i.e. there are no sudden large swings up and down in the variance. This is largely to do with how aberrations of non symmetric systems work, but is far outside the purview of a comment here. If you are interested in that sort of thing, read into NAT, esp. applied to freeform optics. http://www.ncbi.nlm.nih.gov/pubmed/25401809

    Mechanical considerations are certainly valid, but the method of an MTF bench is rather robust and based on having the lens be confocal with a microscope objective. Variance in the location of infinity on the scale doesn’t really come into play, as it is not used to focus, rather the actual image from the lens is.

    Regards,
    Brandon

  • I’m wondering what LR does with out-of-spec Sony lenses that aren’t adjustable. Do you return them for a replacement?

    The question is related to possible purchase of a Sony lens thru the “Rent and Keeper” program and/or LensAuthority. Would such a Sony purchase result in ownership of a lens that was within spec?

  • Aaron Ashley

    Not sure what you built here but your results are completely oppossite of what DX0mark found.

    For instance they found that the sony fe 35 1.4 was about 50% sharper then the sigma wide open(findings that have been confirmed by various anecdotal reports and reviews attesting to the sharpness of the lens)

    The positioned the 90mm fe as the sharpest lens they have ever tested.. Again the nearly surgical sharpness of that lens has been attested to by numerous anecdotal reports and reviews.

    I think its clever that you put 2mm of optical glass in the pathway of the lens because “most sony lenses seemed to benefit from it” but I think maybe your system just isn’t doing exactly what you think its doing. Looks great, very frankenstein but I think you should be looking at what other testers are getting and if your results aren’t lining up you should ask whether your actually testing what you think you are testing.

    Cheers,

    Aaron

    So can you provide an

  • David

    I think the lens correctiondata is written in the raw file. But the raw is not altered imho. Also would it be nice if you would test Sony a-mount lenses since I have had a bad experience with a 24-70 f/2.8 lens (right vs. left side sharpness from 50-70 mm) and would like to see the results on a-mount compared to ie. Nikon. A- mount should alsobe easier to test.

    Best regards David

  • Roger Cicala

    Andrew, I totally agree! That’s what makes all this interesting. Very different tests, very different results.

  • Roger Cicala

    Peter, if you are speaking of variance, they are about the same. MTF, the Sigma is superior.

  • Peter Honka

    for me the sigma 35mm f1.4 variance looks much worse than the sonys… from the diamgram. i am wrong?

  • MarceloBTP

    Thanks you very much for the information Roger.
    Will you add the Loxias later?
    I really admire your passion and the act of sharing this to the public.
    Thank you again!

  • Very interesting article as always Roger.

    Look forward to the next one

    greg

  • Marcelobtp

    Hi Roger, i’ve been suspecting from sony cooked raws since the first mirrorless, but it probably comes from the P&S departament since ever.
    I would really like you to test the loxias vs the old zeiss with almost the same optical formula, they said they are optimized for the new sensors, but maybe they are the same with just cooked raws.
    Thank you very much for this work, i have great admiration for people who are passionate for what they do without thinking on how much money or if they will receive money for it.

  • Andrew

    When I compare your review of the Sony 90mm Macro to this analysis-

    http://www.dxomark.com/Reviews/Sony-FE-90mm-f2.8-Macro-G-OSS-lens-review-Outstanding-optical-performance

    – I am puzzled and struggle to understand the vastly different conclusions.

    It seems like these reviews are talking about two completely different lenses.

    BTW, I recently rented this lens from LR and on an A7R II body it performed exceptionally.

  • I’m slightly surprised that the OLAF bench only tests to 20mm radius from axis. This omits >2mm of extreme corner measurement on the 24 x 36mm sensor, which many find important – sudden death of detail in the corners is a common lens limitation. However, it’s a bit worse than this, as IBIS requires a larger image circle. The sensor can offset itself several mm from the axis (even in APS-C cameras, ±5mm, not sure how far the full frame SS moves) meaning that under many conditions where stabilisation is active part of the exposure may move the imaged area beyond the 43.26 (44mm) required circle (and well beyond your 40mm circle). In theory there are no conditions where SS exposures commences with the sensor off-axis, but in practice most Sony owners know this is not true. Using lenses with very tight image circles like the CZ 16-80mm on APS-C, owners encountered occasional strong vignetting to one corner on random frames, and the cause was that the sensor was not centred when exposure commenced. This happens especially with motordrive sequences using long lenses at marginal shutter speed (say 1/125 with a 300mm lens) as the sensor does not suddenly jerk back to axis position – same for video capture, the SS always floats back to axis and may spend some time off axis.

    For OSS lenses, the circle of coverage naturally has to be larger than 44mm as the stabilisation group may cause the entire field to move though mechanical baffles can trim this. However, as with IBIS, there are conditions where an offset subcircle of the lens coverage may be centred on the sensor, and may also move during the exposure. This is actually one good reason for leaving barrel distortion slightly undercorrected in the lens, and correcting in raw. When either IBIS or OSS moves the recorded area outward from the axis of a non-isometric wide angle view, the subject detail will change scale and in theory this may degrade the corner and edge sharpness of any (super to ultra) wide-angle view taken using stabilisation.

    As a final point, these lenses do not have a fixed infinity focus (as you point out, they don’t even focus on anything at all when not powered up as groups or elements are parked – owners can test this by rotating their E-mount lens a tiny bit after depressing the release catch, while looking through the finder with release without lens enabled – when the lens loses power, you see the world go very blurry). The actual position of the elements/groups and their calibration to infinity is performed by the camera via its sensor after you mount the lens and switch on. Sony E-mount bodies and lenses are not very precisely made, because this process allows for at least ±0.2mm variation in sensor to flange collimation (that’s from my measurements) and possibly even more. I would not be surprised if the system permits up to ±0.5mm. Since the whole design is intended to be self-calibrating and all the lenses focus beyond infinity and also seem in many cases to allow a close focus than the AF confirmation range, how do you get the information from the OLAF sensor to be processed by the camera? I suspect you can’t, and rely on a kind manual magnified live view to achieve an optical collimator infinity setting – which is not exactly the same as a true infinity. Minolta and Sony A-mount lenses are not collimated at infinity but at a specific distance on the original Minolta bench, which I believe is just short of 3 metres. I have no idea what standard Sony, and/or Zeiss working with Sony, actually use.

    You may therefore be testing a lens outside the parameters of on-camera initialisation, though since your rig will have a precise 18mm register, fixed focal lengths should be perfectly handled. Be very careful with wide angle zooms. I recently went through a process of investigating various Sigma 17-35mm lenses after seeing a huge difference between two samples, and it turned out to be a simple variation in the collimation – if the focusing scale was on infinity and the focus was also infinity, the lenses were near perfect – but if the shimming meant the lens scale showed 1.5m (as was common!) when focus was infinity, the outer field would be hopelessly blurred, due to incorrect interaction of the floating/zoom groups and the focusing group (owners of the classic Minolta 24mm Variable Field Curvature 24mm and 35mm designs will understand why – and it’s even worse at 17mm with zoom groups to take into account). A poor lens could be rendered excellent by nothing more than adding a .2mm shim. Given the variability of collimation/register in Sony E/FE bodies – great for keeping costs down and making sensor setup easy – I wonder if some practical variation in results, outside the variability you have found working to a fixed register, might not also be added to the mix.

  • Ying

    Thank you guys for all this work. This is amazing!

    As for the results, I’m kind of disappointed. I’ve owned Sony products for some years now and appreciate their innovation but always put up with the high price of their lenses telling myself they were quality lenses. Now it appears it’s not the case. It seems silly yo spend $1000 for a 90mm lens and find out that you might have bad corners. As someone who was saving up to buy the 90mm macro, I’m definitely having second thoughts.

  • Thomas

    When will be see the first camera that does a tilt of the sensor to help with focusing? This is only half joking, by the way. And would not fully help as a corner is not a first-order effect.

  • Great news!!

    My requests here, apart from the 35 and 55 that you already tested, would be: 28mm f/2, 35mm f/2.8, and both Batis lenses. Pretty please 🙂

    (you rock)

  • Kudo

    Roger,

    Your analysis is causing a stir in the community with the premise that all Sony lenses are junk. What would go along well with you narrative is a visual of a test chart that shows a bad corner or a side. I’m wondering if these sample variation differences are going to be truly visible to end users.

  • L.P.O.

    Brandon,

    I am not sure if we are talking about the same thing. My understanding is that m43 cameras that know the distortion characteristics of a specific lens record that information in the RAW image’s metadata, which allows for metadata aware programs like Photoshop to apply distortion correction after demosaicing the image. (They also automatically apply the correction to JPEG images.) To me that is a very different thing than applying distortion correction to the actual RAW pixels which would require quite some trickery in the RGBG mosaic domain.

    An example below:
    http://www.photozone.de/olympus–four-thirds-lens-tests/740-pana25?start=1
    This is a very typical m43 lens from the point of distortion: if you open it with Photoshop or similar, or look at the JPEG the camera produces, you’ll get a negligible amount of distortion. If, however, you open it with a 3rd party RAW processor that ignores the metadata, you’ll get the true performance of the lens, which in this case has almost 3% barrel distortion. Same thing happens with vignetting and chromatic aberration.

    (As usually, I reserve the right to be completely wrong in every aspect I write. But I don’t think so.)

  • You guys are just amazing, thank you for all the work you put into this!

  • Brandon

    Raoul,

    If you are referencing the 35mm lenses, the EF 35/1.4 II has drastically better resolution than the Nikkor lens. The Canon lens has comparable absolute variability, but relative to its higher resolution the variance is smaller. This is reflected in the better score.

    Regards,
    Brandon

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