What kind of calculations can i do for a camera?

I'm seeing the matter of geometric optic and the teacher ask me for some calculation of the following cameras

nikon 7000
nikon 5100
canon T3i

but what kind of calculations should i do? Any ideas?

Focal length is always fun.
http://en.wikipedia.org/...cal_length

You can always play with the crop factor
http://en.wikipedia.org/...ot_cameras