jann1033
<font color=darkcoral>Right now I'm an inch of nat
- Joined
- Aug 16, 2003
- Messages
- 11,553
background: the 40d only focuses with diagonal cross points at 2.8 or larger apertures. i have a third party lens that will not autofocus. it's f3.5 but in the exif info it comes up f2.8..(I only have one other 3.5 lens, but that comes up as f4,is a canon and focuses fine). phototech has looked at the lens 3 times now and the last 2 times couldn't find anything wrong. they said on their 40d it works great.
so the question i am wondering about is...since the camera is not recognizing the lens at the correct aperture, could the fact it is trying to use the diagonal cross point cause it to not be able to achieve focus at all? i can manually focus it fine but the autofocus will not work unless i get it really close to focus. then if i switch to af it will tweak the focus...this is in macro or normal shooting. it basically is working like a manual focus lens
omega satter if going to try it with their equipment but it makes no sense to me that it works with phototech's 40d and not mine. so i am wondering if somehow a glitch is making the diagonal focus points not work with that lens with my particular camera. the focus seems to work fine with my f1.8 lens and i'm getting another f2.8 in a few days so i can see if it works with that one. but i am at a loss to figure out why it supposedly works there and doesn't work at all on my camera.
so the question i am wondering about is...since the camera is not recognizing the lens at the correct aperture, could the fact it is trying to use the diagonal cross point cause it to not be able to achieve focus at all? i can manually focus it fine but the autofocus will not work unless i get it really close to focus. then if i switch to af it will tweak the focus...this is in macro or normal shooting. it basically is working like a manual focus lens
omega satter if going to try it with their equipment but it makes no sense to me that it works with phototech's 40d and not mine. so i am wondering if somehow a glitch is making the diagonal focus points not work with that lens with my particular camera. the focus seems to work fine with my f1.8 lens and i'm getting another f2.8 in a few days so i can see if it works with that one. but i am at a loss to figure out why it supposedly works there and doesn't work at all on my camera.
