Informative article:
http://www.lensrentals.com/blog/2010/07/how-autofocus-often-works
Personally, I've re-examined my AF settings, once again. I've decided to totally throw over all the advice I've read in recent years from excellent photographers, and to AF like a complete amateur.
AF point selection - big distraction, often wrong, maddening when switching from horizontal to vertical. I now save this for special occasions on static subjects.
AFS v. AFC - I leave it on AFC, except for special occasions. On AFS, the camera will refuse to focus on subjects moving toward me. Subjects are constantly moving toward me on the street. Even though AFS is slightly faster, it loses shots completely every time I shoot street.
AF area [single point, sports, auto] Proficient photographers use single point to put it where they want, or sports to keep moving figures in focus. I use auto. The reason is that it gives me one less thing to think about. And Nikon claims it can "distinguish human subjects," ie, some form of face detection. --On the D4 and D800 this entire system will have been improved, both in hardware and software. --I have failed in a lot of fast moving photos to get the face in focus. So now I let the camera do this for me. Sometimes it fails, it chooses a high contrast shirt over a baby's face, or selects a face in a group I would not pick. But, as a practical matter, I have a higher proportion of subjects in complex situations where the face is acceptably in focus. Every day I am losing shots where the camera guesses wrong, and different shots from those I messed up on my own, but I am losing far fewer shots. By not pretending to be, or even aspiring to be, a better technical photographer than I am, I get better pictures.
Similarly, even I could use AE adjustments based on experience and get more accurate exposures sometimes. By relying on raw latitude, I just have less to think about when I am after subjects and situations. When I have time, I can think and chimp. But that's unusual for me. LR 4, and PS, can let me recover from suboptimal focus nearly all the time.
AF-ON v. Shutter release. Separating exposure from shutter release is so elegant and precise and professional I've been doing it for years, on Canon, Fuji X-100 and Nikon. But once I decided to let the camera select AF, it became pointless. So last week I switched to allowing the shutter release to do AF. Marvelous. I can shoot faster and I can now shoot with one hand when I want to. I was so busy being elegant and professional, I never noticed that my thumb is a little short to reach the AF button on the D3s and had to do a slight stretch.
Another thing I am doing is reducing my aperture about a stop or so. My printing teacher at ICP pointed out the obvious, that this increases the area that seems in focus, especially with the tele FL's that I prefer.
Self-knowledge is a wonderful thing for an artists. I feel much more professional now that I am willing to use amateur settings just because they work better for my style of shooting. And it makes me feel like a rich man --to have worked so hard to acquire advanced knowledge of photography, and to just throw it away.
--
Frank
All photos shot in downtown Manhattan unless otherwise noted.
Thanks in advance for the kindness of your comments or critiques.