Is it a bird? A plane? No, it’s a dust bunny! In fact a flyin’ burrow of them. You’re looking at 1500 identical pixels from the CMOS chip of a Canon 5D dSLR – cropped from two separate images of a blank piece of paper. On the left is the crud-studded photo sensor prior to cleaning. On the right (taken 10 minutes later) is the same section of chip real estate after 3 blasts of dry air from a blower bulb and a few careful swipes with the statically charged bristles of a 728 Arctic Butterfly brush made by VisibleDust.
Best $100 I’ve spent yet.