At 01:07 PM 12/14/95 -0800, you wrote:
>I thought that Bob Atkins used the word "asymmetric", he was referring
>to decentered or crooked lens elements. Note that he distinguishes
>this from a "misaligned" (i.e. not normal to the optical axis), target.

A lens that is as a whole cockeyed, or has a tipped element or section can
look the same on film - and can be sometimes corrected by intentionally
tilting the lens with a shim (sometimes, though, a lens is just plain less
sharp on one side than the other, and it is not caused by a tilted focus plane).
Rarely, I think, is a lens tilted - the tilted effect usually comes from
a misaligned element or section. The above distinction is probably useful, but
I will probably not make it (too old to learn new ways, or something....).
David Ruether