Stephen <mcavoys_AT_aolDOT.com> wrote:
> Is this the sort of thing?
> http://www.reference.com/browse/wiki/Lens_(optics)

  Why not give an url to the original article, which has the images etc.
intact and not raped like in that site?

http://en.wikipedia.org/wiki/Lens_(optics)

  The article says "the most common type of lenses are spherical lenses".
Then in the spherical aberration subsection it says that the spherical
shape is not the optimal for light focusing but it doesn't say what is.

  Why can't they simply give the mathematical function for the perfect
lens surface instead of just saying: "Lenses in which closer-to-ideal,
non-spherical surfaces are used are called aspheric lenses. These were
formerly complex to make and often extremely expensive, although
advances in technology have greatly reduced the cost of manufacture
for these lenses."

  What is the function for the perfect lens surface?

-- 
                                                          - Warp

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