Take a look!

http://en.wikipedia.org/wiki/Camera

http://en.wikipedia.org/wiki/Photographic_lens

http://en.wikipedia.org/wiki/Light_meter

http://en.wikipedia.org/wiki/Shutter_%28photography%29

http://en.wikipedia.org/wiki/Single-lens_reflex_camera

http://en.wikipedia.org/wiki/Single-lens_reflex_camera

http://en.wikipedia.org/wiki/Depth_of_field