[Leica] laws of optics...

[nbeddoe at lehman.com (Beddoe, Neil)]

"Second example, let's imagine a vertical wall with lots of circles painted 
on it (let's call it the Vasarely wall).If you take a picture with the 
lens axis perpendicular to the wall, then ALL the circles will print as 
circles on the picture. If the camera is oblique, then all the circles 
will show as ellipses."

Not quite true.  With anything other than a long telephoto, you'd have to
get close to the wall and this would mean that you'd be viewing the outer
circles from an oblique angle which would render them as ellipses in your
photograph.  This has nothing to do with lens distortion and is just the
normal effect of perspective. 

Neil

------------------------------------------------------------------------------
This message is intended only for the personal and confidential use of the
designated recipient(s) named above.  If you are not the intended recipient 
of
this message you are hereby notified that any review, dissemination,
distribution or copying of this message is strictly prohibited.  This
communication is for information purposes only and should not be regarded as
an offer to sell or as a solicitation of an offer to buy any financial
product, an official confirmation of any transaction, or as an official
statement of Lehman Brothers.  Email transmission cannot be guaranteed to be
secure or error-free.  Therefore, we do not represent that this information 
is
complete or accurate and it should not be relied upon as such.  All
information is subject to change without notice.