In a message dated 3/9/2005 4:37:37 PM Pacific Standard Time, [EMAIL PROTECTED] writes: Well, I'm not a physicist but it seems to me that at small aperatures a very small cone of light is reaching the sensor, while at large aperatures the cone of light is very broad. The narrow cone is more collimated (like a condenser enlarging lens) and images the dust particles better than the broad cone of light (like a cold light source enlarging lens).
Maybe it's more complicated than this, but this explanation seems to make sense and accords well with practical experience with enlargers as well. I stand ready to be corrected by the graybeard mavens here. ;<) Regards, Jim ========== Yup. Sounds right. I was obvious wrong (although I had the basic right principle), but, as I've said before, I am totally ignorant. Funny, the other day as I was changing aperture, I could swear I saw a speck of dust. A LARGE speck. Then I didn't. It was really weird. Marnie
