16-80cz and 70-200G

[bakubo]

I should add that f/2.8 sensors greatly improve wide-angle AF if you have an f/2.8 WA lens.

Back in early 2005 when I got my 7D I posted on another forum about the problems I was having with AF at focal lengths of ~35mm and shorter with various Minolta lenses. I then discovered that my old Sigma 24mm f2.8 was fine though. With the A100 it was the same. The 7D and A100 don't have f2.8 AF sensors though, do they? I have found the same behavior with my A700, but it has the f2.8 sensor so it is less surprising.

[David Kilpatrick]

By the time you get to 28mm the problem is not so great. Even at 24mm, I found focus on the A100 spot on with my 24-105mm zoom. It's when you get sub-20mm that it begins to fall apart, and down at 10mm or 11mm, you can be lucky or not. I had more focus accuracy problems with my 16-80mm CZ (at 16-20mm) than with my earlier 11-18mm KM on the A100.

With any lens, just try the MF assist light test. Switch to MF, and see what range the camera confirms as in focus. Compare it with the same test on a 50mm or a 100mm and you will realise why the 'good enough' AF on wide angles is not good enough - all the time - for guaranteed critical focus accuracy.

David