Focus speed - camera or lens?

[Sam S]

This may be a silly question but here we go...

Is the speed of auto focus mainly down to the camera or the lens? :thinking:

[RichardtheSane]

Both

However
If you buy a lens with quicker AF then you will notice an increase in AF peformance generally regardless of camera model
If however you have a lens with slow AF and you upgrade your body, you probably won't see an increase.

[Sam S]

Cool. So the AF speed on my 400D is likely to be limiting the performance of my 70-200 f4 L?

[AlfaFoxtrot]

Yep both will make a difference.

A better camera will have a more sophisticated algorithm/processor for deciding on the focus - and a better lens will be able to adjust its focus ring more quickly. As to what makes the most difference I don't know...

[RichardtheSane]

Cool. So the AF speed on my 400D is likely to be limiting the performance of my 70-200 f4 L?
I expect so, I found that lens to be very fast to AF on my old 20D

[Sam S]

Thanks!