Frame Spacing focal length

[arseniii]

I noticed it on my Leica M4 that the spacing between frames is much smaller compared to my other Leicas. I constantly use 25mm lens attached to the M4 in question and was wondering if this is the wide lens that exposes a little bit more of the frame compared to let's say 50mm focal length? Also, what puzzles me is that the spacing is not consistent, sometimes it's a bit thicker and at times a bit thinner. I am afraid a trip to a tech is necessary 🙁

 

[Tim Gray]

Yes. My frame spacing is tighter on my Ms with a 21 compared to longer focal lengths. I always assumed the frame mask must have some type of bevel that lets high angle of incidence rays sneak past where the more perpendicular ones of longer focal lengths are blocked.

Unevenness - I don’t know.

 

[John Bragg]

Same with my M6 and 28mm Elmar compared to 50 Summicron. Only happens with my M6 and no other 35mm camera I own.

 

[arseniii]

Just looked at my older negs where I used this lens on the other camera and the spacing is wider and even. Another interesting observation, the vertical frame border is not a straight line but curls a little making the spacing thinner with 25mm. Just like this ) (. This is common to all of my M-mounts.

The M4 that has narrower spacing just came back from DAG CLA and I think he might have not noticed it. I think the combo of camera's narrow frame spacing and wide lens makes it look too narrow. I still got my 36 frames on the roll and Coolscan can read the frames pretty accurately. So, I will ask DAG if this is something that needs attention.
In the meantime, I shot several frames with 50mm and as soon as it gets darker outside I will load the tank and develop the film to see if the spacing is not even with another focal length.

 

[arseniii]

Yes. My frame spacing is tighter on my Ms with a 21 compared to longer focal lengths. I always assumed the frame mask must have some type of bevel that lets high angle of incidence rays sneak past where the more perpendicular ones of longer focal lengths are blocked.

Unevenness - I don’t know.

I think it's related to how far the lens goes inside the camera. Wide angle lenses get very close to the film plane making the angle of light rays much wider. Thus, getting further to the margins of the frame.

 

[arseniii]

UPDATE: The same M4 with 50mm lens produced even and nice spacing. Go figure the mystery :bang:. May be something with the tension of the film when I loaded it. Hmmmm

 

[Dwig]

I think it's related to how far the lens goes inside the camera. Wide angle lenses get very close to the film plane making the angle of light rays much wider. Thus, getting further to the margins of the frame.

Correct. This happens this way because the film aperture that functions like a "mask" is not in contact with the film. The film rails create a space between the aperture and the film.

 

[ellisson]

"The distance between frames varies. Non retrofocus wide angles sneak some image under the aperture plate in the camera. The 21mm f/3.4 Super Angulon makes much bigger negatives than a 50mm lens, and the old long focus 135mm Elmar and Hektor lenses make smaller than normal negatves. There has also been some variation over the years in the exact size of the cut out in the camera"

This quoted from a comment in another forum from ~2003 in reference to very narrow frame spacing on an M6 camera with a Super Angulon 21/3.4 lens, a comment/response by Al Kaplan, now deceased, but a prolific contributor to RFF. I have had the same experience on my M3 camera using the 21mm/f3.4 Super Angulon.