Please help w/ 30D autofocus question

[derrickdehaan]

<p

[derrickdehaan]

<p>Wow, all of my text somehow didn't make it.<br>

Folks, here is the situation....I used a Sigma 50-500 on my 40D with great results. Loaned the lens to a friend with a 30D body and he gets horrid results with focus. So my simple question is, does anybody know of any focusing issues with the 30D body and a lens with a max 6.3 aperture? The lens communicates to the body that it is 5.6 I am assuming for autofocus purposes. My friend tells me he is using solid support and the fastest shutter speeds he can. So, lets say that it is not operator error (which it could be). Anyone ever run into this? He said he stopped by a camera shop and they told him the lens was front focusing. I say nay, nay. I even emailed him the lens test chart photos I took with that lens before I sent it to him. Its spot on, although a tad soft at 500mm. <br>

Derrick</p>

[KenPapai]

<p>Well... the AF in in a 40D is much improved over the 20D/30D. </p>

<p>It is visible LIGHT and its attendant contrast that AF systems loves, not what the lens "reports to" the camera's CPU.</p>

[derrickdehaan]

<p>Thanks for responding Ken. Yes, I agree with your statement. I was wondering if anyone has encountered a similar situation with a 30D and a 6.3 lens and autofocus. My friend is shooting wildlife in bright sunlight and getting what appears to be major front focusing.<br>

The lens worked well on my 40D, and his 70-200 2.8 appeared to work fine on his 30D body. <br>

Can someone suggest a good way to test a long telephoto under inside controlled conditions. The test chart at 45° is a pain with a very long minimum focusing distance.<br>

Derrick</p>