Fine Focusing

[avanides]

I tried to find the most applicable category for this question, so please forgive me if I've made a forum boo-boo.

I've had this focusing problem for a while now, and its bugging the heck out of me. If I'm shooting people, for example, I can never get their eyes in focus. It seems like the most intimate portraits have the subject's eyes in crisp focus, but when using a wider angle and a so-so slr viewfinder (I'm using a digital rebel and canon 17-40) I just don't know what to do.

Can anybody help me with my focusing problems? From what I've read about medium format photography, cameras like Hasselblad apparently have some sort of magnifier in their viewfinder to solve this very problem. What can I do? Thanks for all your help.

[Tim Gray]

How are you focusing/composing?  If you use the centre focus area on the eyes then half press and recompose what was in focus originally may no longer be in focus after the recompose, particularly if you're using a fairly wide aperture.  Don't know what options you have to select the focus point, but try to select the focus point such that any recomposition is minimized.  As an expirement, focus as you're doing now and don't recompose and see if you get a sharper shot.

You also may have a lens callibration issue.  Lay a measuring tape on a table and focus (with tripod and mlu, or remote if no mlu to eliminate other factors) on a specific mark - say 24" from about a 25 - 30 degree angle and fairly close using as large an aperture as possible.  You should clearly see the range of dof, but the sharp part should be bang on the 24"

[Jonathan Wienke]

It seems like the most intimate portraits have the subject's eyes in crisp focus, but when using a wider angle and a so-so slr viewfinder (I'm using a digital rebel and canon 17-40) I just don't know what to do.

You may find reading Focus-Recompose Sucks to be helpful.