Sony 200-600 zoom: 4 cameras, two lenses

ByDMcA
Sony 200-600 zoom: 4 cameras, two lenses

If you would rather head straight to a concise summary, the TL;DR is at the foot of the page — or jump directly to the FAQ.

This is a summary of all the work I have done on Sony cameras and the Sony 200-600 zoom lens in 2020. I tested 4 cameras and two copies of the lens. These tests have involved checking the focus accuracy and/or focus point position of around 6000 photographs

Sony 200-600 zoom: 4 cameras, two lenses: results summary

Here are the main details for each camera test session in chronological order. The first link for each camera test takes you to my detailed post on the results. The “examples” links show AFV.exe (Auto Focus Visualiser) screenshots that clearly illustrate the Sony cameras missing the bird or missing focus. The orange circle (sometimes hard to see) is the final focus point, the green squares are the AF points also used. All the shots are out of focus (and obviously should have been in perfect focus).

A7R4 – Gigrin farm: Kites, 1000+ shots of 1000+ out of focus (100% OOF). Returned 200-600 lens to dealer and obtained new lens. I deleted these images, so no examples.

A7R4: Hawk Conservancy Trust (HCT) Andover: Mixed shooting, New lens: 831 out of 854 out of focus (97%) Examples

A9: HCT, Andover: Mixed shooting: 717 out of 1460 out of focus (28% for ‘easy’ conditions, 51% overall) Examples

A7R3 HCT, Andover: Mixed shooting: 130 out of 198 out of focus( 66%) Examples

A6400 HCT and Pen Ponds: Mixed shooting: 2247 out of 3441 out of focus (65%) Examples

Are these results an outlier?

Sony 200-600 zoom: 4 cameras, two lenses, awful results

You would hope so, but I am not so sure.

  1. Mirrorlessons (ML) got a 90% hit rate with the A9. I got a 72% hit rate with the A9 at the Hawk Conservancy Trust, Andover (HCT) in the morning session. In both situations there was plenty of time to get an initial focus lock, which favours the A9. The difference between my 72% and ML’s 90% is almost certainly because in the HCT session, birds are also flying directly at you at close range, which does not happen at the kite feeding station . This says to me my results are in the ball park. Where the A9 and every other Sony camera was less effective was in circumstances when there is very limited time (1-2 sec) to get a focus lock, as for example in the HCT afternoon session. As far as I know, that kind of shooting situation was not tested by Mirrorlessons. As my morning session test results with the A9 and 200-600 lens are consistent with the results of Mirrorlessons, it is clear that the lens was not defective.
  2. Some people have said this is due to camera copy variation. I don’t think so. Exactly the same egregious focussing errors show up on all 4 cameras (and in both copies of the lens).
  3. The A7R4 and 200-600 problem has been reported by others, so that issue is not isolated to my cameras and lens.
  4. So far at least, this is a unique data set, and that may be part of the reason some people have such difficulty in accepting it. I have not seen anyone do tests this carefully and under such challenging BIF conditions, on 6000+ images. In particular, I have never seen anyone do large scale focus point checks with tools like afv.exe.
  5. The Sony phase detect focussing system has some unique features which may explain their results. I go into aspects of that in this post.

Conclusion

Let’s start with the A7R4. There is clearly a huge system flaw between the camera and the 200-600 lens. It happens for some people, and not others, and it may be that my example was one of the worst. But no responsible camera manufacturer would a) let that happen, and b) never acknowledge or fix the problem.

For the other 3 cameras, I think my results for BIF photos in challenging test conditions are representative – they are not an outlier or the result of operator error. I think that when you properly test the Sony cameras in tough BIF conditions, they are just not as good as people say they are.

Also let me make it clear that this is not a targeted attack on Sony. I spent thousands of euros expecting to make Sony my main system for birds in flight. When the A7R4 failed to perform, I bought or rented more Sony cameras hoping I would find better AF performance. When I didn’t see better performance, rather than just put this down to experience and move on, I did 6 months of detailed analysis of all the failed shots, and that is what you see here.

I cannot say I am happy about this – I wasted a lot of money, time, and worst of all, hundreds of potentially great BIF images on Sony. But I am not attacking the company, or its loyal users. My aim is to alert others to this data, and find out more about how the problems I found could be avoided by me or others in the future.

TL;DR
  • Sony A7R4 + 200–600: 97% out of focus (831/854 shots)—system-level flaw, even with a replacement lens.
  • Sony A9 + 200–600 + HCT (hard conditions): 51% out of focus overall; 28% in easy (morning) conditions—not the claimed 90%.
  • Sony A7R3 + 200–600: 66% out of focus (130/198 shots); A6400: 65% out of focus (2247/3441 shots).
  • All four cameras fail identically—not copy variation or operator error; 6000+ test images show consistent pattern across two lens copies.
  • A9 performance (72% accurate, morning only) aligns with Mirrorlessons’ 90% claim, but rapid-fire scenarios (1–2 sec) expose AF weakness unique to challenging BIF conditions.

Back to the article.

Frequently asked questions

Isn’t 97% out of focus on the A7R4 just a copy defect?

No. The replacement lens showed identical failures. The pattern repeats across all four cameras tested (A7R4, A9, A7R3, A6400) and both lens copies. This is a system-level problem, not random defects.

You got 72% accurate in morning conditions but claim 51% overall failure—which is correct?

Both. Morning (predictable subjects, time to lock): 72% accurate. Afternoon (rapid reaction, birds at close range, erratic flight): 49% accurate overall. The A9 excels in calm conditions, fails in chaos.

Doesn’t Mirrorlessons say the A9 gets 90% accuracy?

Yes, but their tests used a fixed kite-feeding station with predictable bird behaviour. I tested at Hawk Conservancy Trust with erratic close-range flight. My 72% (morning, controlled conditions) aligns with their 90% claim. The 51% overall reflects realistic, chaotic BIF scenarios they didn’t test.

Did you make operator errors, or is this user error?

Unlikely. I used the same settings across all 6000+ images, same tripod, same techniques as Mirrorlessons reported using. All four cameras failed identically with both lens copies. The pattern is systematic, not random operator variance.

What’s the difference between 72% and 90% accuracy—isn’t that just normal variation?

No. 72% vs 90% is 18% absolute—too large for margin of error. But more importantly, the afternoon session exposed a more critical gap: A9 at 49% vs EM1x at 55% under identical chaos. That difference is tiny (6%), but it reveals the A9’s weakness in 1–2 second reaction windows where there’s no time for servo tracking recovery.

Back to the article.

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