Sony FE 135mm f1.8 GM Early MTF Results

As is sometimes the case, I got access to a couple of pre-release copies of the new Sony FE 135mm f1.8 GM lens. Of course, if I get access, it gets MTF bench tested. I mounted the first one, sipped my coffee and then lost my mind and started shouting various expletives, enough to bring Aaron running in from the other room to see what I’d broken.

I hadn’t broken anything; I just saw MTF curves higher than anything I’d ever seen in a normal-range lens. (Lenses like 400mm f/2.8 super telephotos, are about this high. But those are super telephotos. And f/2.8.)

Anyway, I tested the two copies we had and sent a subtle note of congratulations to some friends at Sony. The note turned into a video conference with one of the designers of the lens and some phone calls that went like “you can write up those two copies” and “no, I only write up 10-copy sets”. This turned into Sony giving me to access to 8 more copies and permission release the test results early.

Sony 135mm GM Rentals

So, this write up is my usual MTF post; 10 new-from-box copies tested and averaged. They are Sony’s own copies, however, not the usual lenses we’ve bought off the shelf. I’ll repeat the test in 6 weeks when we get our own copies, but I have no reason to think it will be different. And just to be clear, Sony didn’t hover over me or approve my results; they’ll see this blog post for the first time exactly when you do.

A Bit About the Lens

I was permitted to share a bit of the background I was given on this lens; it has some new features. The paired linear motors moving two separate focusing groups haven’t been done before. There have been some attempts at paired focusing groups in zooms, but not in primes, and the pairs have generally been one ring and one linear motor. Also, these are new linear motors (depending on how you count, 4th generation) that are much more powerful and robust than earlier ones. This is the same motor design used in the Sony FE 400mm f/2.8 GM OSS lens, which we showed you in the teardown of that lens.

If I understand correctly, this focusing system allows the 135mm f1.8 GM to execute up to 60 AF instructions per second. {Correction: I misunderstood this part during the teleconference. What was said was that the A9 can give 60 instructions per second, and that this and the 400 f/2.8 come closest to keeping up with that.} That is faster than anything else Sony has made and does it to a higher degree of accuracy than they’ve achieved before.

Optically, the lens has what Sony’s engineers call the largest ‘extreme’ aspheric element ever made, and it’s up in the front of the lens, which they say helps both sharpness and bokeh. I think ‘extreme’ aspheric may be more of a marketing, than an optical, term. But what was very clear is they have (and I saw micrographs to demonstrate it) been able to polish this aspheric to a smoother degree than has been possible, reducing or eliminating any onion-skin bokeh.

Sharpness Testing Sony 135mm GM

There were more features, like the 11-blade aperture and the aluminum-magnesium composite chassis (the same material used in the Sony 400 f2.8 again). I’m not trying to make this into a lens review; it’s just my report of MTF tests. But I wanted to let you know that I was really impressed by the discussions I had with Sony engineers. As many of you who follow this blog know, ‘impressed’ has not always been my opinion of Sony’s lenses. But I’m impressed this time.

MTF Results

Let’s make this simple and straightforward. In the center, that’s the highest MTF I’ve seen on a non-supertelephoto lens. The highest. Let’s put particular emphasis on the purple line, which is 50 lp/mm. That’s a higher frequency than any manufacturer tests (that we know of), appropriate for fine detail on the highest resolution cameras. We would consider an MTF of 0.5 at 50 lp/mm to be very acceptable. This is hugely better, nearly 0.8 in the center. We’ve never seen that kind of resolution before., 2018


The MTF drops away from the center, of course, but even at the very edges, the readings are still quite high.

Let’s compare it to the Sigma 135mm f1.8, which until today was the sharpest 135mm we had tested. In the outer 1/2 of the image they’re pretty even, but in the center half, the Sony GM is dramatically better, especially at higher resolutions., 2018


I’ll also throw up a comparison with the Zeiss 135mm Batis, which is really excellent, although not wide-aperture. The Batis has a considerable advantage since it’s being tested at f/2.8. Even at f/1.8, though, the Sony 135mm GM is clearly better in the center half of the image. 2018


But Wait! There’s More!

Aaron brought up that this was the highest center resolution either of us remembered seeing on standard testing, with 50 lp/mm reaching a ridiculous 0.78 MTF. We have, in the past, tested lenses at a higher frequency for ultra-high resolution sensors (150 megapixels). We found that a lot of lenses that were really good at standard frequencies died quickly at higher frequencies.

So we tested the 135mm GM up to 100 lp/mm, something we don’t normally do., 2019

These results are insanely good. At 100 lp/mm the Sony 135mm f/1.8 GM has a higher MTF than most excellent primes do at 50 lp / mm. If you don’t speak MTF, basically that means this lens can resolve fine details that would be a blur on excellent lenses.

Back when we were doing that ultra-high resolution testing we tested all the lenses stopped down to f/2.8 or f/4; there was no way to get the kind of resolution our client needed otherwise. So we tried the 100 lp test at f/2.8. Honestly, I thought the resolution wouldn’t go up all that much. As is so often the case, I thought wrong., 2018

No lens we’ve ever tested has resolved 100 lp/mm this well at any aperture. One other lens was close, but I can’t tell you the name of it. We were under such strict nondisclosure that we never referred to it by name. It was just referred to as ‘the lens in question’ and was a huge prototype. But even that lens wasn’t quite this good at 100 lp/mm.

What does this mean for you? Well, in a couple of years if you are shooting a 90-megapixel camera, this lens will be the one that wrings the most detail out of that sensor. Right now it looks at your 43 megapixels and goes, “that’s cute.”


This has been an MTF test. It has only been an MTF test. If it had been an actual lens review, I would have 762 images showing you pretty models, dramatic landscapes, and bokeh examples. Lens reviewers will do that in a while; be patient.

But as far as the test goes, the results are pretty simple. This is the sharpest lens we’ve tested. Period. (At last count, that’s out of 300+ lenses tested.)


Roger Cicala and Aaron Closz

March, 2019

Author: Roger Cicala

I’m Roger and I am the founder of 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 Equipment
  • Sorry, Andy. We have been getting slammed with spam and some of it offensive so we’ve had to set the bots to the tightest filters and it is definitely stopping some posts.

  • I’ve noticed that the LR spam filter sometimes blocks comments with links in it. So your post may not have been deleted by a human, but merely sent to some spam purgatory.

  • Andreas Werle

    As you perhaps deleted my Post, because I inserted a link to the respective lr-blog-post, i will try it again (without a link):

    Thanks for this Test, Roger. If I remember well you did the “Ultra-high resolution Testing” at 200 lp/mm. The Sigma 135/1,8 made 35% contrast (200 lp/mm) and the Otus 85 mm ca. 40% (200 lp/mm), both at f4. As the Sony did 70% contrast at f2.8 for 100 lp/mm and the Otus 85 ca. 70% contrast at f4 and 80 lp/mm, the Sony is or may indeed be a little bit better. But this is of course due to the fact, that the Sony is not as fast as the ca 4 years “old” Zeiss. Anyway, well done Sony.

    Greetings Andy

  • Friedhelm

    Will you really see it on a 42MP cam compared to the Sigma 135/1.8?
    I doubt it…

  • Eddy Kamera

    that huge prototype tho…

  • ABSOLUTELY!! And then the boxes make very handy small parts bins.

    Although note to Thorlabs: Don’t send “Memphis barbeque flavor” chips in the snackboxes going to Memphis. We know better.

  • We haven’t been able to keep them in stock long enough to test them.

  • Marvinski

    I don’t think that is entirely correct. Technically the 85ZA is a rebadged of the Minolta 85/1.4G(D), the Zeiss touch is the extra element at the end for the extra correction to meet the Zeiss standard. Which magically get the Blue badge and image quality rival the legendary Minolta 85/1.4GDL.

    More on this is…I’m sorry for all the Sony Zeiss fans is….non of the Sony Zeiss are designed by Zeiss…they are all designed in house by Sony, and “approved” by Zeiss….So technically most if not all the early A mount ZA was a rebadge/modified Minolta lens (either from prototype or old design)….hence that why I like the Amount ZA than the Emount ZA

  • Mike Earussi

    That’s what I thought. This also means that any future increase in sensor resolution will also negated by hand holding.

  • oratrix magna

    it would be interesting a comparison with SAMYANG 135 mm F2 ED and with the Voigtlander 110 mm f 2.5 apo macro … exceptional lenses …

  • Unrest

    A bit of an exaggeration to say the GM puts the 135 Art “to shame”.

  • Out of curiosity, will we be seeing MTF results of the Sony 24 1.4 anytime soon? Other sources have reported that’s the best 24 1.4 out there.

  • They’re the best part of any Thorlabs order. 🙂

  • bdbender4

    Well son of a gun. It’s not the same as it ever was.

  • Ernest Green

    Looks great. Big fan of your articles. Love me a blazingly high MTF 50 line pair chart. I wonder though if these relative differences (super high performing lenses vs. “normal” ones) can be realized at normal resolutions everyone views photos on. I’m guessing usually a cellphone (instagram) or best case, flickr, full screen on, say, a 24″ monitor. Or even printed 20×30. In other words, when does your typical medium grade prime or zoom start to fall short in real world use?

    I suppose billboard size it might start to make a difference? How about physically large medium format glass. Easier fine detail resolving power due to the size of the glass alone?

    i’m no stranger to spending money on good glass if it’s called for. But we live in an age where lots of “normal” glass is really good for practical use. And your occasional large print.

    I’ve gotten great photos out of normal lenses. I don’t know how well this will show on this chat thread (compression and all that) but here’s just a regular old Canon 6D (I have an EOS R now) and Canon 100/2 prime. ( From a moving car. And this shows fantastically at very high res. out to the corners. Seems to show fine if you click on it:

  • Søren Stærke

    Nice Thorlabs snack boxes in the background 😉

  • mclaren777

    I never trust manufactured-supplied stuff for reviews (lenses, cars, etc) so I look forward to your testing of retail units.

  • OK, at infinity focus the Sony 90 Macro is not great compared to other similar range macros because sample variation is extremely high. At close focusing tests it’s excellent and variation is lower. But the best single copy 90 Macro I’ve tested at infinity is not as good as the average 135mm GM.

    Hopefully that clears things up, although I’m sure we’ll have to have 3 or 4 ‘my 90 Macro is awesome’ comments. There are good copies at infinity out there. In fact over half of them are really good. Not most, but over half.

  • What Mike said below for certain. But there will be a different ‘look’, especially out of focus areas. I think that’s more of a preference thing, and less of a this is better than that thing. Nikon, for example, tends to value that smooth side-to-side look in their lenses more; while Sigma and Sony tend to value highest resolution.

    For me, I like the even side-to-side kind of lens in a wider angle (maybe partly because that’s harder to pull off) and give me center resolution in the longer ones since I tend to use those as portrait or action lenses. (Probably should mention I also tend to center my subjects in shots and then crop for placement rather than shoot them off center.)

  • I have tested the Canon, not to 10 copies, but close. The Sony is a bit sharper in the center of the image, but I think we’re getting into the ‘splitting hairs’ area here.

  • In a zoom? No. But don’t fall into the ‘zoom sharp as a prime’ trap. Center? sure. Edges? Nope.

  • My own question is more about copy-to-copy variation. These were very consistent but I won’t consider that real until I see off-the-shelf lenses tested. But certainly most of the off-the-shelf lenses should be this good. Perhaps nearly all.

  • Mike, I think if conditions and technique were excellent (say mirror lock up, manually focused, mounted on a tripod shot) you’d notice the center difference on a high-resolution camera. But I agree with you; hand-held normal shooting I doubt the Sigma and Sony are noticeably different.

  • Mike Earussi

    Your bench tests are all well and good (or exceptional) but now try and get that resolution in a real life outdoor portrait session handheld (it is designed as a portrait lens after all). Even with Sony’s IBIS I’d be very surprised if the max resolution could be obtained. Still, this would make for an interesting test if you choose to do it.

  • Mike Earussi

    It’s the ultimate portrait lens. A landscape lens needs to be more consistent across the frame since the edges are also important.

  • Mike Fewster

    The role of Minolta in Sony lens design is interesting. The whole Minolta lens department went to Sony. Minolta lenses, when they went for it, were just superb. It is probably impossible to determine all the DNA today but I’d love to hear from someone inside the lens division of Sony discussing the amalgamation of the Minolta optical engineers into the Sony camp.

  • DrJon

    Thanks, I feel there must be a level of correction where the performance takes a dive as the pixels are just getting spread too thin, but don’t know if that could be built into bench testing, you’d need to know the algorithms (the parameters being in the lens)? I find it interesting that on some lenses the DXO corrections give me a noticeably different FoV to standard m43 ones, for example.

  • CheshireCat

    I wonder how much being “Sony’s own copies” is affecting the results.
    I was impressed by how much sharper my brand-new off-the-shelf Canon EF 135/2 came back after being sent to Canon for proper tuning.

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