Here's a view of the light defraction around the iris diphragm in a camera lens. The lens is set for F/5.6. You can imagine how proportionally much more of the lens' image-forming area would be taken up by the difraction bands at F/22! This is why smaller lens openings can cause loss of image sharpness.
The circles are likely caused by a few dust specks on the lens. The difraction bands are made visible by using near-monochromatic light from an LED and some crude collimnation tricks.
Images taken in a controlled environment or with a posed subject. All subject types.