Originally posted by UncleVanya To verify the problem pop another lens on that doesn't show any spots that you notice and take a picture of the blank blue sky or white wall using f/8 or smaller (f/11 works well) to get the spots to show up. Then change lenses and do it again. The spots should not change position as I understand it.
I was about to suggest this, but UncleVanya spoke first. I have had spots on my photos and it was definitely dust on the sensor. I don't know if I've ever had dust inside my lens, but I'd certainly think I had to have at some point, but could not tell it. I have seen demonstrations of huge cracks and flaws on lenses and the photos still turned out fine, remarkably. So a little dust in a lens should not be a problem.