Abysmal Performance - 27 Nov 2020

The rumors appear to have been true. The Sony 200-600mm f/5.6-6.3 G OSS lens on the Sony a7RIV has a serious autofocus issue for birds in flight (BIF). I've known it, and have been frustrated by the results of the combo. What makes it painful is that the combo is amazing for stationary subjects and even soaring birds. But, if it has to focus on anything moving then the tracking is horrendous.

I took a ride down to Lake Erie to photograph a flock of gulls to see how bad the issue was. I started with the lens at 200mm and autofocus worked great. Even at 400mm its wasn't bad, but focus points drifted away from fly-by Ring-billed Gulls when the camera was telling me it was tracking the bird just fine (the little green boxes are locked on the bird as it flies but images are blurry). At 600mm its awful. Maybe 1 sharp image out of the burst. But very disappointing.

I even tried changing the Creative Style of the camera to Vivid, and it seemed to improve overall performance, but wasn't a fix-all. I shot 1800 photos in admittedly low-light on low-contrast subjects (gray gulls against gray skies) but performance was abysmal. When it did catch that 1 in a 100 shot the results were impressive.