In article <4n6hj5$2jn@doc.zippo.com>, dterry@freenet.vcu.edu says...

>I just bought a used FD 24mm f2 lens that seemed to be in really
>good shape. When I started using it I noticed an objectionable
>ghost image whenever I pointed the lens at a bright object.
>(such as lightbulb). The image is very distinct and moves w/the
>direction of panning.
>Stopping down doesn't seem to help. Do all wide angles do this, or
>is it an artifact created by the camera's pentaprism?
>The front and back coatings look like they are in good shape
>(the purple, blue, green and pink colors all visible, etc.).
>Should I return this lens???

This is a tough test for any lens, and most lenses will show
spots, ghosts, aperture reflections, etc. when aimed at a bare
lightbulb, particularly if the background is dark. To see if
an effect is caused by the lens or the viewing system, hold
the camera/lens still while moving your eye relative to the
eyepiece - VF effects will move, but lens effects will not,
if the VF optics are the cause. I would try the lens in normal
picture-taking situations (including some difficult ones, like
interior photos with windows included [or just outside] the
angle-of-view) to see if the lens is suitable for your use
before returning it. All lenses are optical compromises,
and it is easy to find tests that would make any lens look
bad. It is useful to know the faults of your lenses so that
you can work around them (or return the lens, if the fault[s]
makes the lens often difficult to work with), but it is not
useful to avoid lenses that have relatively minor faults, or
faults that show up only under unusual conditions - otherwise,
you would have no lenses to shoot with! ;-(
(Note that the above advice is given by an
unrepentant perfectionist "lensaholic"........;-)
Hope This Helps