The Coolpix 8800 is a compact digicam, after all, and has got a much smaller sensor than any DSLR. Therefore it sports a very large depth of field even with the lens wide open. This comes in handy when you want to have a large depth of field (see PIGEON and STATUES). On the other hand it makes it almost impossible to seperate your subject from the background or to use selective sharpness (TREES). To get this effect in the BLACKBIRD picture I zoomed in and moved as close as possible to the subject.
But you can not take full advantage of the large DOF because the smallest aperture offered by this camera is f/8. No problem at normal distances, but often not enough when doing macros (see IVY and FLOWER). I had to look for a flat part of the tree to get an almost completely sharp chunk of LICHEN.
I guess this limitation prevents problems caused by diffraction: light passing close to the edge of the diaphragm is bent out of focus. The smaller the aperture, the bigger the portion of "bent" light and the fuzzier the image. I once read about a rule of thumb, that when the ratio f-stop/focal lenght is higher than 1/4, diffraction starts to have negative effect on sharpness. f/16 at 8.9 mm would be almost 2/1 ... But it had not been a problem for my Canon G2 ...
I think, the "stars" produced by strong light sources at f/8 and short focal lengths is the result of diffraction (GREIFENSEE).
Please correct me if I am wrong!
--tinu--