Just for fun and knowledge I will throw in another bit of info.  We see compact digitals advertised as having perhaps a "10X" zoom.    In binocular speak, 10x is 10 power or a magnification of 10.  What about this 10X zoom?   It might very well mean the camera lens will zoom from lets say 18mm to 180mm..wow, a 10x zoom!  

50mm is considered 1:1 magnification wise.  A 100mm is 2x in magnification or binocular terms.   A 10X magnification will take 50mm x 10 or a 500mm lens.  The 180mm on the compact with the 10x zoom is getting 180mm/50mm = 3.6 magnification.  That is 3.6X in binocular terms, far from a real 10X magnification.

Yikes, I have not been out of bed long enough to do this sort of post...Tom.

If what I have said is incorrect and it is me who is confused, someone please correct me..thanks.