Fri 14-Dec-12 05:18 AM | edited Fri 14-Dec-12 05:20 AM by elec164
One other thing that struck me about those spots is that in looking at the EXIF data the image was taken at f/4.2. Also they all appear as being elliptical and about 95 to 100 pixels on the long side (about 600 microns) making them sort of uniform in shape. It also makes them HUGE!! I would think they would be easily spotted with the naked eye looking at the sensor.
If you look at this engineering chart ,average atmospheric dust is only about .001-40 microns. Even my oil spots if I remember correctly were only about 70 to 140 microns in size.
Of course that assumes your example was a full uncropped capture. If so than it appears to me that your spots are quite unusual and not the typical dust. Typically dust would be of varying sizes and irregular shapes. These seem rather uniform in size and shape.