Looks like my speciality is small birds after all :-P

[Tomsch]

ohenry, the Sigma 50-500 lies to the camera, at 500 the EXIF will show fstop at 5.6. In that way full auto function is maintained. Is that what you mean?

[Eric CAN]

ohenry, Tomh is right, to get full auto, it will lie to the camera saying it's F/5.6 , in reality it's F/6.3.

I never shoot at that aperture, my minimum aperture is F/8, which keeps satisfactory sharpness at 500mm

Cheers

[ohenry]

Originally Posted by Tomsch

ohenry, the Sigma 50-500 lies to the camera, at 500 the EXIF will show fstop at 5.6. In that way full auto function is maintained. Is that what you mean?

Thanks Tom, that's exactly what I was asking (knowing that AF can get flaky and non functional beyond f/5.6). Eric, yes I understand what you're saying about aperture, I was concerned with AF and TOm answered that. THanks