Briefly, the Poser camera focal length and fStop settings work on the depth of focus pretty well as they do for a real camera. The important thing to remember is that we cannot see the difference between an in-focus and an out-of-focus blob until it looks big enough to our eye. "Big enough" is a matter of angles, and it depends on the distance of the picture and its size. So your snapshots can look bigger than an advertising hoarding. What I'm getting to is that Geep's sample pictures are very small, and to show the difference in focus he had to use a very small fStop. The default in Poser is fStop=2.8, and that will show blur in a screen-filling web image. For an example, I often use a focal-length setting of 85mm for my pictures of people. For that, the in-focus range is the equivalent of about 10 inches deep at f2.8, and it gets shallower as you get closer. For an idea of the way things work out, look at this PDF for the Leica Noctilux f/1.0 5cm lens, which has some real-world depth-of-field diagrams.