Thu 03-May-12 12:58 AM | edited Thu 03-May-12 01:01 AM by ajdooley
Charles -- Unfortunately DSLRs are for the most part, computers with lenses! Like computers with keyboards, they do exactly what we tell them to do, and not necessarily what we WANT them to do.
I think your issue is that when you get sharp faces, that is where the focus point is set -- on a face. When you don't, it is probably set on the background in the distance.
I recommend single point focus, and either moving the focus point until it is on the eyes of one of the people, or focusing by moving the camera and focusing on a person, depressing the shutter button half way and recomposing, or using the focus lock function on your camera to hold fous while you compose. Then if people are a different distances in your photo, you'll also have to have a smaller f/stop to get adequate depth of field.
If you are unfamiliar with the uses of the many buttons and functions on your camera, good books like Digital Darrel's "Mastering the D700" on this web site or Dave Busch's book on your D700 are much better than the Nikon manual. They have good photos to illustrate things and are written by someone who is using the camera and has visited many of the pitfalls -- not just someone who is telling how something SHOULD work!
FYI, something I learned years ago: divide the number of people in the group by 3. That is the number of exposures you have to take to get everyone's eyes open. In other words, if you have 9 people posed in a group, shoot 3 images -- one should have everyone's eyes open... hopefully! This is not science -- just experience and odds.