Originally posted by monochrome You need enough contrast for the CDAF to work. At longer distances in room light the AF point often doesn't have enough. Try to find an edge in the same focus plane (brown hair to face, dark shirt to light background), hold focus and recompose.
I have been trying that but its not working as expected (though it might be working). For instance, I tried focusing on a person with brown hair so the contrast between brown hair and white skin was there, but the camera ignored the face hair contrast and reached out behind the person to focus on the white curtain that has less contrast. I have noticed that it likes light subjects. It doesn't like a face with skin/hair contrast, but it likes a white wall. I tried a white wall (with a little texture) and it focused. I tried the ceiling that is much smoother and it focused. I tried a white metal door that was nice and smooth, and it focused. In the same area and same light levels, it had much more difficulty with a face. I was under the impression that a smooth white surface was the worst thing for contrast AF. Fyi I'm using firmware 1.3 now. Perhaps its a matter of the lighter objects having more reflected light so it can lock easier?
Regardless, I guess its a matter of finding what kinds of things it likes focusing on so the same advice you gave would apply as far as focusing, locking and recomposing.
I'm thinking a lot of problems with this camera can be solved by just learning the camera better. Compared to my ist-ds, as well as half a dozen point and shoot cameras I currently have (including a medium size sony that originally cost about $800 so it wasn't just a cheapo or a pocket camera), the camera is just weird. It has very strange behavior. I wonder if it is just something with mine? I do seem to be able to work through some problems just by learning the quirks of the camera.
One side note. I am primarily using a few auto focus zooms. I do occasionally try to 40mm to compare.
Also, the camera doesn't have so many issues at closer distances where the AF assist light has effect. I have been concentrating on longer distances to learn how to work through the problems. At some point I will start learning MF lenses on it but I would like to learn to use both AF and MF lenses. I also have quite a few lenses so it may be a matter of finding the ones it likes.