Equipment

An Update and Comparison of the Sony FE 70-200mm f/2.8 GM OSS

About a month ago, Roger posted his MTF bench results for the Nikon 70-200mm f/2.8E FL ED AF-S VR (TL;DR: it’s optically superb), and down in the comments there were some requests to compare it not only to the Canon 70-200mm f/2.8L IS II in the article, but also to the Sony FE 70-200mm f/2.8 GM OSS. There were MTF charts linked:

These are not very good looking results, especially for a $2600 lens, but Roger wasn’t sure if they were correct results. In his comments after these charts he said:

Let’s kind of keep this here for right now – I haven’t published it because I’m still a little uncertain about the results. Sony has suggested that a change in cover glass thickness might improve the results some. Not dramatically, but some, off-axis. This lens also has to focusing motors and we have to focus it electronically via a camera to test. I’m not absolutely certain that ‘setting it at infinity focus on the camera’ and ‘manually focusing on a an object at infinity’ are absolutely the same. So take these lab results with a grain of salt. On the other hand, they do seem to agree with what we see in real world results.

I try hard not to put out anything until I’m just absolutely certain our results are correct. We’re doing some stuff here that’s pretty cutting edge, honestly. No one does 4 rotation MTFs, for example. I’m pretty certain these are good results, but not absolutely certain. So I’ll post them in this discussion on my own site but I’d rather not see them reproduced all over the internet yet.

Someone suggested we try all three 70-200s on their respective camera bodies and shoot the same detailed scene with each, then share the files. But that would involve three different cameras and wouldn’t really be an apples to apples comparison, would it? Roger suggested he have one of our photo techs shoot all three lenses on a Sony camera with adapters, admitting that adapters add another variable, but there would be some good practical implications.

So I did just that. I took all three lenses, the Canon 70-200mm f/2.8L IS II, the Nikon 70-200mm f/2.8E FL ED AF-S VR, and the Sony FE 70-200mm f/2.8 GM OSS, and I shot our test chart with all of them on the Sony a7R II. For Canon, I used a Metabones T Smart Adapter IV, and for Nikon, I used a Novoflex Nikon to Sony E adapter. I manually focused all three lenses to get the most consistent results, and here’s what I got:

Full Resolution Examples are Available Here

If you view the charts at 100%, you’ll see that they’re consistent with the MTF charts Roger generated for all three lenses. The Sony just isn’t that great, and that’s really disappointing considering the price tag and how long customers have had to wait for that lens to be available. But if you need f/2.8 and working autofocus, it’s really the best option out there for Sony mirrorless cameras.

Author: Joey Miller

I’m Joey. I love cameras, especially old film cameras, and I can’t remember the last day I didn’t take a photo. Digital cameras are great, and they keep me employed, but I also still like processing my own film. I’m stuck somewhere in the middle. I shoot every single day, no matter what.

Posted in Equipment
  • john sweeny

    Have you ever talked with a DXO “expert” I have. I have been saying it for a while now. Some pros should get together and create a new pro analysis for cameras and lenses. It takes months for DXO to even get to the new lenses. It shouldn’t be that difficult. Simplicity is the best policy

  • Brandon Dube

    Nominal or best case, yes.

  • Danno

    Thanks. Just trying to understand what was up with their numbers. Do the computer generated ones represent a “theoretical” level of performance, basically?

  • DxO Mark results are out. But they don’t indicate problems with our testing methods. We’ve redone them three times now and discussed them with Sony engineers at length.

    What DxO Mark’s results probably indicates is this lens does much better close up than at infinity, where we test. Or that they got a really good copy. If I publish the MTFs for the best copy at each focal length, we’ll they’d be outstanding, too. Which is why I don’t test 10 lenses and then give you the best result out of 10.

  • Sony published computer generated MTF charts, just like all manufacturers do. Our results on actual measurements differ, like they always do. We have now run MTF tests on several different sets of 70-200 GM MTF charts and the results stand. It’s a good lens. It’s not the best in class.

  • Brandon Dube

    10 years is not a long time to be in a multi-faceted industry. If you’re around Canon and Nikon and Zeiss who have been doing this for 75+ years, you are a spring chicken.

    No one from Minolta is still with Sony, to my knowledge.

  • Liberty_666

    Interesting post, Brandon. It was nice to learn why confocal microscopy uses a telecentric principle — you explain it very well. You had mentioned that in optics, Sony is a young company, which might explain why they use aspherics. But didn’t Sony acquire Minolta about 10 years ago? I would assume that many Minolta engineers are still designing lenses for Sony, where they can draw upon 90 years of expertise as a company. I don’t know Sony’s history well, so I am only speculating.

  • Danno

    Sony published a vastly different MTF chart on their product page for the lens: https://www.sony.net/Products/di/en-us/products/lenses/lineup/detail/sel70200gm.html

    Have you re-run the tests on any later copies from them? Did they ever offer a comment regarding these results?

  • lwestfall

    Clearly that Sony is heavily decentered with a sharp right side (at least as good as the Nikon, maybe a bit better) and not so good on the left (actually neck and neck with the Canon in most areas). How about you show the right-side MTF and not just the left-side MTF for the Sony? And have you since tested more copies of the Sony? It would be great to see how they all look in terms of MTF but also centering. It does concern me if a lot of the Sony lenses have this decentering issue. Thank you for the great work!

  • Piero Monteverde

    Did you disable the OS when putting the GMaster in the tripod? It seems not to affect the Nikon but made a huge difference with the Sony. Once I disabled the OS, both lenses tested very close side by side, even having the Nikon adapted to the a7rII.

  • bbflynt

    ePhotozine has posted their updated, very favorable review today. High sharpness marks on their MTF charts.

    Sample pictures are odd in that some of them aren’t focused well. (e.g. the men bowling on the lawn — focus plane looks to be behind the guy rolling his ball.)
    https://www.ephotozine.com/article/sony-fe-70-200mm-f-2-8-g-master-oss-review-30557

  • Magnar W. Fjørtoft

    Saying that the Sony lens is garbage is pretty big words. I would really like to see how you could back up such a claim. Any links?

  • Munchma Quchi

    Roger – what the hell is wrong with DXO? Are they being bribed? Inept? I lost faith in them a long time ago when their reviews on the FE55 seemed to all be calculated against pixel count and not actual tests. But now they are pissing all over your work here and have marked the Sony as the greatest zoom ever with 38mp sharpness.

  • Munchma Quchi

    I had a blog that documented this problem for more than a year called Sonyvnikon. It had over 5000 readers and then Sony’s lawyers came after me. But yes, I used Imatest and the Sony is garbage.

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