It is normal for dust to collect on the inside of lenses, particularly zoom lenses, where zooming can draw in dust. Digital sensors also attract dust, which is increased by frequent changing of lenses.
- Should I be worried about getting dust inside my SLR?
- Is it normal for there to be tiny dust particles in a new lens?
- How to properly clean a camera
- What is the best way to clean the sensor on a digital SLR?
- How effective are in-camera integrated sensor cleaning systems, and have they improved?