Originally posted by LeGoGubbe Yes I checked both against the window to easily see. But nothing.
Originally posted by ChristianRock Might be worth putting another roll in it, maybe a cheap one, just to make sure it wasn't the developer doing something funky...
Between shots are you putting the lens cap on? Between shots, is it possible that sunlight is entering the viewfinder in the back of the camera?
I am fairly certain it is a light leak. Even with the lens off and the mirror up and pointing the camera at the sun, you may not see the leak.
When you do the second roll test, you will want to test the roll for the front or first curtain, and for the rear or second curtain. For all the shots, try to shoot low key subjects that are relatively mid tone to dark.
a) For the first/front curtain test, after each shot, immediately advance the film and then let the camera sit with the lens without a cap towards sunlight for at least 20 minutes.
b) After perhaps doing this twice, you could shoot in rapid sequence; each shot only a few seconds or a minute apart.
c) For the second/rear curtain test, repeat as above, but do not advance the film between shots. Repeat at least one time.
d) Now try both techniques with the lens cap on between shots.
e) Now try both techniques with sunlight intentionally hitting the rear viewfinder window for at least 20 minutes.
Take good notes so that when you get the negs back, you can identify the cause.
I could also imagine on an older camera areas under the mirror or in the dark box that could no longer be matte black creating unwanted reflection of light during the exposure, but that doesn't make much sense for your night shots.
IF it is a leak in the first/front curtain, then just get into the habit of never advancing the film until you're just about to shoot.
IF it is a leak in the rear/second curtain, then just get into the habit of always advancing the film after shooting.
IF the problem goes away with a lens cap, then problem solved.
IF the problem only happens when the viewfinder is exposed to a good dose of sunlight, then always store your camera in a camera bag or use black camera tape or anything as a viewfinder cap while not shooting.
In general, fixing a shutter curtain is more expensive than buying a replacement camera.