p.2 #2 · Tamron 150-500mm Z mount. Any one bought it?
Joseph Marney wrote:
I believe this is simply an artificial limitation imposed on the Sony bodies, not a limitation of the AF motor, but I can test that on the Z8 and report back.
There will be no FPS limit with a Z8/Z9, that is an artificial limit Sony imposes for the most part. It has nothing at all to do with the AF motor speed. If you shoot a static subject where the AF motor isn't even working, you are still FPS limited. Lenses like the Sigma 70-200/2.8 use very fast linear motors and are limited to 15 FPS.
The reason some camera/lens combinations have legitimate FPS limits is because the aperture diaphragm can't operate fast enough to keep up with frame rates depending on your exposure settings. This is more of a problem in the DSLR world where focusing is always performed with the lens wide open and it has to stop down and open back up for every single frame. It's less of an issue with mirrorless where autofocus is typically performed at your selected aperture to eliminate focus shift, but with really small apertures and some older/cheaper lenses there are still some FPS limitations with certain body/lens combinations.
