AF Speed

This is a probably a stupid question

Is the speed of AF a function of the lens or is it dependant on the camera.

I do know that there is no such thing as a stupid question.

honestly it works both ways.. if you compare say a 1dIII to a xsi you will find that the MK III is much faster and more accurate vs the xsi with the same lens on.. if you pair that 1dIII with say a nice L prime it will be even faster

Thanks for the prompt reply. Its kind of what I thought.

Yup, definitely both.

My 1D3 drives my 85L a lot faster than my 5D can move it.

On the other hand, a lens like my 35L is faster on my 5D than even the 1D3 can drive the 85L. Put the 35L on the 1D3 and focus is nearly instantaneous.

Yes, both and also how you have the camera set up and your technique. But, here in the lens section, you are going to hear about the lens mostly.

I don't mean to hijack the thread, but does the same hold true for autofocus accuracy too?

I imagine it would both in terms of getting more light to the focus sensors and in more precise positioning of the lens itself. Is that right?

Again, both. My 5D is noticeably more accurate than my 40D was with the same lenses.

So much so that I sent my 40D in to Canon to check the focus system. It came back, within spec.

bohdank wrote in post #8199712
Again, both. My 5D is noticeably more accurate than my 40D was with the same lenses.

So much so that I sent my 40D in to Canon to check the focus system. It came back, within spec.

I'd agree with this. THe center point of my 5D is more accurate than the one on my old 30D, but all of the user selectable points on the 1D3 are better (faster, more accurate) than the center on the 5D.

I have my sights on adding a 1DMK2 for it's AF and fps. The latter being what I miss the most from my 40D.

bohdank wrote in post #8199756
I have my sights on adding a 1DMK2 for it's AF and fps. The latter being what I miss the most from my 40D.

You're on the right track, I noticed a much higher keeper rate when I bought my 1DMK2 than with my 20D. Although, it took some getting used to with all the focus pts. on the 1D.