hello everyone, I have an early 80's Nikon FM that works great.... If you don't up the shutter speed past 1/60th of a second. Past that point it only exposes the bottom 1/10th of the film. While investigating what could be causing this, it looks like the shutter blinds/blades are moving slower than the mirror, so the light is only able to reach 1/10th of the film. Thinking this may be a lubrication issue, but don't want to use the wrong stuff or go down the wrong rabbit hole if it is a different issue altogether. Don't want to bring it in for a legit repair as the body itself isn't worth as much as the repair would cost. Thanks in advance!