22nd January 2003, 03:02 PM
Diffraction Stars and Ghost Images
Dear ClubSNAP experts:
When photographing point sources of light (e.g., street lamps) at small apertures, I notice that they become 10-pointed diffraction stars.
I sort of understand that this is due to the point source of light being diffracted by the corners of the aperture blades. This would then mean that the diaphram controlling the aperture comprises 10 pieces of blades.
However, this is contradictory to another observation when using the same camera: When shooting into the sun or other strong light sources, I also often encounter ghost images or flares that are 5-sided spots.
So, my question is: does my aperture have 5 or 10 blades??
Last edited by ckhaos; 27th January 2003 at 06:19 PM.