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by jake36 on Tue Feb 11, 2020 12:54 pm
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Has anyone tested/determined the actual maximum frame rate when using a Sony A9 or A9II in AF-C mode with a 3rd party E-mount lens (not adapted from another mount)? I'm referring to E-mount lenses from Sigma, Tamron, Tokina... anyone other than Sony. If different lenses give different results, that would be of interest as well.

With Sony's own E-mount lenses, the A9/A9II max frame rate is 20 fps, but with adapted lenses it's 10 fps. I have tested and verified both of these numbers... But what I'd like to know is whether 3rd party E-mount lenses behave like native Sony lenses in this regard, or like adapted lenses.

Thank you in advance.
Armand
 

by E.J. Peiker on Tue Feb 11, 2020 5:53 pm
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Sony, unlike Canon and Nikon, license their lens interface specifications including the electronics to third party lens manufacturers. So basically a third party lens that has AF and EXIF are actually using the Sony specification and they did not need to reverse engineer the mount so the performance will be the same as with a Sony lens. In the case of Nikon and Canon, companies like Sigma and Tamron actually have to reverse engineer the mount which is why sometimes their lenses won't work with new models of camera until they do a firmware update.
 

by jake36 on Tue Feb 11, 2020 7:38 pm
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Yes, I get all that, but I'm asking if this really works as it should in practice. Do you have the ability to test? It would be a very quick test! I don't own any 3rd party E-mount lenses... yet.

There is in fact reason to ask: I saw a YouTube video posted by a photographer who claimed he could only get to 10 fps with 3rd party E-mount lenses on A9... I wish I'd saved that link, but I didn't. The same claim (as applying specifically to Tamron lenses, in this case) also appears in a thread on Sony Alpha Rumors:
https://www.sonyalpharumors.com/first-image-of-the-new-tamron-70-180mm-f-2-8-fe-lens-mounted-on-the-sony-a7iii/#disqus_thread
Here's that quote:
Shang-Hsien Yang Mb2 months ago
The Tamron lenses can't support the 20fps on the a9/a9II though. In fact, the 17-28 and 28-75 could only do 10fps according to my own tests.

Searching for practical experience proving the YouTube and SAR guys were full of it, and that Sony interface licensing actually leads to the expected results, in practice.
 

by E.J. Peiker on Tue Feb 11, 2020 8:48 pm
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I have both Sigma and Tamron lenses and there is no difference in frame rate but that's on the a7R4, I don't have a a9 to test it on.  The 70-180 comment is nonsensical since the only thing anybody has ever touched is an early prototype.  There won't be production versions of this lens with final firmware for several months yet.

I can't find the comment on the 17-28 and 28-75 but my first question would be what shutter speed he was using?  Almost no camera can do maximum frame rate with shutter speeds slower than about 1/200s in continuous focus still photo mode due to needing to AF track between shots.  But if it is real, it might be that the Tamron lenses need a FW update.
 

by jake36 on Wed Feb 12, 2020 1:49 am
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You misunderstood my previous post. That SAR post/comment made perfect sense, in fact. It appeared in a *thread* about the upcoming 70-180, but at no point did anyone say they had any experience with that particular (upcoming) lens. I quoted the comment in its entirety (so there's no need for you to search), but I linked the thread just in case you're interested in the context. That specific comment expressed the poster's concern that the upcoming Tamron 70-180 lens would support a max frame rate of only 10 fps on the A9/A9II, based on his/her experience with current Tamron lenses (17-28 and 28-75). A concern which I share. Perhaps a relevant FW update does exist for Tamron lenses, but I haven't seen evidence for that. Plus, your previous post suggests such a FW update shouldn't be needed anyway, due to how Sony is licensing their specs.

It's quite a stretch to argue that the SAR poster shot at the wrong shutter speed to test the max frame rate properly. My testing of the A9 with Sony 100-400 shows the following max frame rates using AF-C:

Shutter (s)     max fps
1/10              5
1/13              5
1/15              6
1/20              7.5
1/25              10
1/30              10
1/40              15
1/60              15
1/100            15
1/125            20
1/160            20
1/200            20
1/250            20

Since the SAR poster reported a max frame rate of exactly 10 fps with Tamron lenses, he/she would've had to set a shutter speed of exactly 1/25 or 1/30 s to be camera-limited to 10 fps and not realize it. Possible, but unlikely. At any other shutter speed, he/she would've gotten a different max frame rate (higher or lower than 10 fps), as shown above. While you're basically right that to reach the camera-limited maximum of 20 fps you need to shoot the A9 at 1/125 s or faster, that bit of info is just not all that significant in this context.

Furthermore, as I said, I have come across other posts on the web which similarly claim that the A9/A9II are limited to 10 fps when using 3rd party E-mount lenses. But given the general degree of accuracy of information found on the web, I posted my question here, in case someone here can speak from direct personal experience...

With all due respect for your own broad experience, of which I am aware, the A7RIV is not relevant here since that body is too different from the A9/A9II. My question specifically addresses the A9/A9II, and not any other Sony bodies. The fact that the A9/A9II bodies have a reduced max frame rate with adapted lenses (namely, 10 fps) raises the possibility and/or suspicion that 3rd party E-mount lenses *might* also have that lower max frame rate, and thus not behave like native Sony-branded lenses (which reach 20 fps). Answering my question about the A9/A9II by analogy to the A7RIV doesn't work here.

So back to my original question, which still stands.

If I might make a suggestion: perhaps let's give someone who actually has the relevant A9/A9II experience a chance to answer, rather than continuing to speculate. If someone like that exists and is willing to respond... Thank you.
 

by Scott Fairbairn on Wed Feb 12, 2020 8:14 am
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jake36 wrote:
You misunderstood my previous post. That SAR post/comment made perfect sense, in fact. It appeared in a *thread* about the upcoming 70-180, but at no point did anyone say they had any experience with that particular (upcoming) lens. I quoted the comment in its entirety (so there's no need for you to search), but I linked the thread just in case you're interested in the context. That specific comment expressed the poster's concern that the upcoming Tamron 70-180 lens would support a max frame rate of only 10 fps on the A9/A9II, based on his/her experience with current Tamron lenses (17-28 and 28-75). A concern which I share. Perhaps a relevant FW update does exist for Tamron lenses, but I haven't seen evidence for that. Plus, your previous post suggests such a FW update shouldn't be needed anyway, due to how Sony is licensing their specs.

It's quite a stretch to argue that the SAR poster shot at the wrong shutter speed to test the max frame rate properly. My testing of the A9 with Sony 100-400 shows the following max frame rates using AF-C:

Shutter (s)     max fps
1/10              5
1/13              5
1/15              6
1/20              7.5
1/25              10
1/30              10
1/40              15
1/60              15
1/100            15
1/125            20
1/160            20
1/200            20
1/250            20

Since the SAR poster reported a max frame rate of exactly 10 fps with Tamron lenses, he/she would've had to set a shutter speed of exactly 1/25 or 1/30 s to be camera-limited to 10 fps and not realize it. Possible, but unlikely. At any other shutter speed, he/she would've gotten a different max frame rate (higher or lower than 10 fps), as shown above. While you're basically right that to reach the camera-limited maximum of 20 fps you need to shoot the A9 at 1/125 s or faster, that bit of info is just not all that significant in this context.

Furthermore, as I said, I have come across other posts on the web which similarly claim that the A9/A9II are limited to 10 fps when using 3rd party E-mount lenses. But given the general degree of accuracy of information found on the web, I posted my question here, in case someone here can speak from direct personal experience...

With all due respect for your own broad experience, of which I am aware, the A7RIV is not relevant here since that body is too different from the A9/A9II. My question specifically addresses the A9/A9II, and not any other Sony bodies. The fact that the A9/A9II bodies have a reduced max frame rate with adapted lenses (namely, 10 fps) raises the possibility and/or suspicion that 3rd party E-mount lenses *might* also have that lower max frame rate, and thus not behave like native Sony-branded lenses (which reach 20 fps). Answering my question about the A9/A9II by analogy to the A7RIV doesn't work here.

So back to my original question, which still stands.

If I might make a suggestion: perhaps let's give someone who actually has the relevant A9/A9II experience a chance to answer, rather than continuing to speculate. If someone like that exists and is willing to respond... Thank you.


I have both those Tamron lenses(although I'm in the process of selling the 28-75) and an A9, so as soon as I get a chance I'll do a test. I'll try it tonight if I can and post the results. 
Also, I believe shooting uncompressed raw slows the max frame rate on any lens, I'll test both options.
 

by Scott Fairbairn on Wed Feb 12, 2020 1:59 pm
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Ok, I had a chance at lunch to try it out with the 28-75 Tamron. Using the A9, continuous focus, continuous high, single point, 1/1000 sec shutter at f2.8 in BOTH compressed and uncompressed I get 10 fps. I also tested against a Sony lens and I got 20 fps as expected. So it appears Sony did not give away all their secrets.
 

by jake36 on Thu Feb 13, 2020 12:04 am
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Thank you! That is exactly what I was interested in finding out. I very much appreciate your taking the time to respond, and to run the test.

BTW, all of the results I listed above were obtained with compressed RAW. Since you brought up the point about type of RAW, I tested again at 1/800 s with uncompressed RAW, using Sony 100-400 on A9, and I got a frame rate of 12 fps instead of the 20 fps I got with compressed RAW. I find it interesting that you don't see a similar dependence of fps on RAW type when using the Tamron lens (which you state above is capped at 10 fps regardless of RAW type -- but this is already slower than even uncompressed RAW with a Sony lens). Just out of curiosity, I then decided to RTFM. The A9 manual (2018 version) completely agrees with my number of 12 fps with uncompressed RAW (p.80, footnote *3). I note that the manual further states (same page, *2): "When in AF-C, the speed of continuous shooting varies depending on the attached lens." But so far, the only such "variation" in continuous shooting speed I've come across is when shooting with Sony vs non-Sony E-mount lenses!

Strictly speaking, the above only applies to Tamron E-mount lenses, and maybe only to the specific model tested. But it certainly makes me suspicious of all other 3rd-party E-mount lenses.

Thinking ahead... if non-Sony E-mount lenses perform like *adapted* lenses in terms of max fps, on the A9, this also begs the question as to whether it's worth "upgrading" to a non-Sony E-mount lens if you already own a good-quality lens in another mount and a decent adapter. But that's probably best left as a topic for another time. (It was in fact discussed, in part, in a recent thread.)


This will definitely have an impact on my thinking about any 3rd-party E-mount lenses that I might consider primarily for shooting action.

Very appreciative of the responses received -- very helpful indeed.
 

by jake36 on Thu Feb 13, 2020 8:38 am
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One additional thought: Out of an abundance of curiosity, I checked the A9II manual. In these regards (max fps) it appears to have exactly the same specs as the A9.
 

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