[2form]

I just purchased a DA 40mm F2.8 online secondhand and noticed it has a spec of dust internally on the front element. The dust spot is located approximately halve way between the center and the outer edge of the lens. To date I haven't noticed anything on my images that may have been caused by this dust. Am I likely to see evidence of this dust spot on images the further the lens is stopped down? What other environmental or mechanical analysis could I execute (if any) to test the effects of this dust so I can avoid its potential adversities in future operations? Also, is it feasibly to consider having this dust removed professionally? I've heard of dust getting into zooms but thought this an unusual occurrence in a prime.

[kevinschoenmakers]

Internal dust is nothing to worry about. I have an old lens that has more dust inside that most vacuum cleaners, and it doesn't hurt the image quality at all.