[APML]: Questions.....

[charles@jon.cjfny.org]

I've been taking some nice shots with a Pentax 6X7 300mm f4 and Nikkor
180mm f2.8ED lenses. I just had some questions for the more experienced
guys out there:

1. I noticed that for several of later images on the same roll, the left
side of the image would be severely out of focus, while the right side
was fine. Did this relate to the fact that the film was in the camera
for a few days? Perhaps the negative developed a curl sitting in the
spool?

2. What are the effects of high thin clouds on nebulae images? In one
shot taken through a DS filter, Deneb had a prominent halo, but the
North American nebula seemed fine.

3. At what temperatures does the focus become altered, as far as the
infinity marker is concerned? I had a couple of shots that seemed out of
focus for no apparent reason. The temperature was above 0 C though. Can
thin clouds cause stars to appear out of focus?

4. My friend sandwiched two 120 format negs, but the results appear more
grainy than the original images. I thought sandwiching reduced apparent
grain. Is it a better technique to work with two 4X5 internegs made from
slides than simply sandwitching the original negs?

Thanks for any replies....

Charles