Dark area on left side of frame

[Gary NJ]

I have this issue with all lenses that I own. Type of film doesn't matter. It's not on all frames and maybe less so frequent now (about 1 or so frames per roll).

 

[Sirius Glass]

I have this issue with all lenses that I own. Type of film doesn't matter. It's not on all frames and maybe less so frequent now (about 1 or so frames per roll).

That sound like a light leak on the left side of the camera or film back.

 

[Donald Qualls]

I have a roll of film in the camera now, but I locked up the mirror in the self-timer mode and saw that on the bottom right of the mirror (as the camera faces away from me), there is a small patch of the flock missing. The patch is circular shaped. The paint under flocking is black. Could this be the cause?

Your #22 is a film defect. The light and dark are reversed and the demarcation is curved.

However, the little circular patch of missing flocking is exactly what I was suggesting you look for. Even black paint will reflect more light in a more "sourced" way (hence cast a shadow) than flocking. It'll still be scattered, hence nearly even distribution over the frame height, the distance change will give the fade-off to the right side of the frame (left in the camera), and image light on the patch might lead to the slight variation in the sky on the original image, kind of like the image from a very large pinhole.