The Blue Angels from my front yard today during their annual weekend of shows in Seattle for Sea Fair. I must admit, in this downsized version they just look like birds flying in perfect formation. ;-)

The weird noise in the top corners demonstrates a potential problem with my camera. I noticed it starting to do this grid patterned noise a couple of months ago when shooting the sky, or long exposures with and without noise reduction, or underexposing even by just a stop (sometimes less, and sometimes just in shadow areas--I have much worse examples of it than this). It seems to be occuring more often. It actually produces an interesting textured effect sometimes. Anyone know anything about this? Is it normal noise from the Rebel XT (350 D) that I'm just starting to see, or something strange going on?