Focus problems

[santer36]

i have a canon xti. i recently had a wedding and gave my camera to a friend to

take come pics. to make things easy for her i set it on program mode and told

her about the exposure settings and how to change that and explained the

histogram to her. all done in about 15 min. when i got the pics back.

exposures weren't too bad, BUT a BIG problem was the focusing. she knew to hold

the shutter in half way let the camera focus and push the rest of the way. she

mostly used my ef50mm 1.8 and also did a few shots with the ef-s 17-85 IS. alot

of pictures were focused on the background and left my wife and i very out of

focus. can anyone tell me what i could have done to help her with this. as i

tried myself earlier today and i sometimes have the same problem. when in

program mode i do not get to choose the focus points through the view finder.

they are all lit up. am i missing something here? thank you for the help!

[mike_kim]

If you are in P-mode and one-shot AF mode, you can manually select AF point (read page 57 of your manual) and lock the focus for recompose. In the future, you may want to show how to use a center focusing point (or manually select focus point), press shutter release button half-way to LOCK the focus, then recompose (while holding down shutter release half-way).

[arie_vandervelden1]

My suggestion is to leave all AF points on and tell your friend to center the subject. The AF should snap on to subjects in the foreground. You can then crop later for proper composition. Centering the subject is intuitive to most people, especially when they see the crosshairs through the viewfinder. Focus-recompose-expose is compicated for non-photographer types. Furthermore you may get focus errors between focus and expose if the subject moves.<P>

Also, rather than shooting in P with the 50/1.8 you could try setting it to AV with an fstop of 2.8 or 4. P mode may choose f/1.8, and 50/1.8 is very unforgiving of focus errors.

[mike_kim]

By the way, to get out of auto focus selection, you need to press [+] key (one that looks like dotted cross surrounded by a rectangle), press any arrow keys to select the focus point (or use your thumb wheel), then press "set" key to select the point. Also you may want to instruct the novice to focus on the eyes and learn to keep the focus lock (keep the shutter release pressed HALF-WAY). I found turning the focus lock beep on helpful for novice--whenever it beeps, new focus lock is aquired. If you hear the beeps during the recomposing/reframing, you know you will have out of focus shot :)

[picturesque]

Most important is to use One Shot and not AI Focus or AI Servo. I agree with Arie re using automatic focus point selection.

[santer36]

that would be the problem! i had it set on AI Servo. thanks guys! my stupidity screwed up alot of my own wedding pics. thanks guys!