Mari,

I took a photography class and all I brought home from that was a one page print out. I did write down a few terms that I found out the meaning to later.

Dioptre or Diopter - A unit of measurement of the optical power of a lens.

Low Dispersion - Prevents chromatic aberration because it concentrates & directs the wavelength of light more effectively onto the camera's lens.

Abberration - Also called color fringing - The effect in which light passing through a lens becomes blurred & produces a fuzzy image on the film.

BTW, the class was way over my head but I did learn some things that can be very useful now. Like to bait wild animals peanut butter and corn is good to use.