[net.rec.photo] Dumb questions about lenses

warren@ihlpl.UUCP (w. montgomery) (07/16/85)

I have had some lens problems with my Fujica AX3 camera and have not
gotten any useful answers from a camera store on them, and wondered
if anyone in netland could help.

I recently acquired a Vivitar 28-135 zoom for the camera, and on the
first role I shot, all of the pictures shot through that lens seem
about 2 stops under exposed.  I had the store I bought the camera
from double check everything and nothing looks wrong.  I have
examined the lens myself and it looks fine.  When I switch between
this lens and the lens that came with the camera set to the same
aperature, the exposure reading stays the same.  It is possible, but
very unlikely, that I had the film speed set wrong the whole time I
shot the first role.  (Unlikely, since shots done with other lenses
on that roll came out fine).  Does anyone out there have an explanation?

My second problem is that ever since I started switching lenses on
the camera, 3-4 shots per roll come out absolutely black (as if
never exposed).  I have never figured out whether the black frames
correspond to lens changes, but I see no reason why they should. 
Again, the camera store people have no explanation.  (My other
accessory lens is a tamron 80-210 zoom that I have used for 3 years
without trouble).

			Warren Montgomery
			ihnss!warren

nelson@cca.UUCP (Dale Nelson) (07/26/85)

> I have had some lens problems with my Fujica AX3 camera and have not
> gotten any useful answers from a camera store on them, and wondered
> if anyone in netland could help.
> 
> I recently acquired a Vivitar 28-135 zoom for the camera, and on the
> first role I shot, all of the pictures shot through that lens seem
> about 2 stops under exposed.  I had the store I bought the camera
> from double check everything and nothing looks wrong.  I have
> examined the lens myself and it looks fine.  When I switch between
> this lens and the lens that came with the camera set to the same
> aperature, the exposure reading stays the same.  It is possible, but
> very unlikely, that I had the film speed set wrong the whole time I
> shot the first role.  (Unlikely, since shots done with other lenses
> on that roll came out fine).  Does anyone out there have an explanation?

Sounds like you have a problem in the lens stop-down mechanism - if the
aperture tabs or cams or whatever is used for your camera do not mate
exactly with the aperture stop-down tabs in the lens, the camera may be
trying to (and succeeding in) stopping the lens down too far. Since the
exposure reading through the lens is always taken at full aperture, the
readings between several lenses will probably remain similar. You should
check the lens for mechanical mismatch with the camera (maybe take it
back to the seller and try another and see if the problem vanishes).
 
          Dale Nelson
          CCA, Cambridge  617-492-8860