Photographic Glass Lens

Hi,

I will try to model my digicam as a first try.

I came across a problem: I do not know enough about glass lenses…
Are lenses made from two parts of a sphere, the middle part removed and
“North pole” and “South pole” attached to each other ?
How can I rebuild the shape most exactly?

A front view of the camera without nice “original” reflections and
refractions is like a diamond made from glass…

Thank you very much fro any help in advance !
mcc

I suggest you start here http://en.wikipedia.org/wiki/Lens_%28optics%29