CV lenses on M - larger image size on neg?

[.JL.]

I have a CV21/4 and a CV15/4.5 for my two M bodies.

On the negatives, images produced by these two lenses are larger than 24mm x 36mm. This is easily spotted from the narrower gaps between frames. Is this normal for CV lenses, or even for LTM lenses in general, when they are used on a M-mount body?

Adding to my confusion, there appears to be some fuzziness in resolution on some of the images taken by the 15/4.5. I realize there are many possible factors affecting resolution/sharpness, but I am starting to doubt my sample of lenses and the LTM-M adaptor...

 

[Artorius]

Corners?

Corners?

Are you refering to corner sharpness wide open? If so, it's normal.
On both my Leicas(M3 & M6) I use 135, 90, 75, 50, 40, 24, and all are larger than 36x24on the negs.
My Nikons F5 & FM3a expose exactly 24x36.

 

[Shac]

JL – If I understand your first question correctly I’m pretty sure it’s not possible for the lens to affect the negative size in this case. What does determine the boundaries of the image on the film is the opening of the film gate in the camera. Spaces between frames can vary because of small inconsistencies during winding on the film.

 

[jgeenen]

Of course it could be possible to have *slightly* larger negatives with true short focal length lenses than with retro focus lenses, standard or telephoto lenses: As the "light source" within the lens is closer to the film, the angle light beams hit the film edges is smaller and therefore lights somehow "behind" the film frame. This has nothing to do with CV or LTM, just with the lens design and is true for lenses, too.

 

[Xmas]

The leitz 21 and 28mm symmentic (old) lenses and J12, give the same effect, the M shutter frame is some way forward from the film frame.

Noel

 

[PHOTOEIL]

The leitz 21 and 28mm symmentic (old) lenses and J12, give the same effect, the M shutter frame is some way forward from the film frame.

Noel

The same for the Hasselblad SWC/M (Biogon 38 mm). The neg's are some shat 'longer' due to the fact that there are two roll's, on the up and down side of the film-holder, and the light beams are passing some what 'around' and between the roll and the film. It makes the neg's about 2 mm higher. This dous not happens with the Distagon 40mm.

 

[.JL.]

Are you refering to corner sharpness wide open? If so, it's normal.
On both my Leicas(M3 & M6) I use 135, 90, 75, 50, 40, 24, and all are larger than 36x24on the negs.
My Nikons F5 & FM3a expose exactly 24x36.

Yes, the softness is around the corners. I shot at f/5.6 though.

 

[x-ray]

Of course it could be possible to have *slightly* larger negatives with true short focal length lenses than with retro focus lenses, standard or telephoto lenses: As the "light source" within the lens is closer to the film, the angle light beams hit the film edges is smaller and therefore lights somehow "behind" the film frame. This has nothing to do with CV or LTM, just with the lens design and is true for lenses, too.

Exactly correct. When I was shooting the 21 SA f3.4 it created frames that almost touched. The farther the element extends into the camera and wider the lens the more this happens.

 

[.JL.]

JL – If I understand your first question correctly I’m pretty sure it’s not possible for the lens to affect the negative size in this case. What does determine the boundaries of the image on the film is the opening of the film gate in the camera. Spaces between frames can vary because of small inconsistencies during winding on the film.

That was what I thought too, but my negatives show larger images from the CV lenses very consistently - they are closer to the sprockets and there are less space between frames. Images taken with M lenses show normal spacing as any other 35mm cameras I've used. And this is something I can tell without measuring precisely.

 

[.JL.]

Exactly correct. When I was shooting the 21 SA f3.4 it created frames that almost touched. The farther the element extends into the camera and wider the lens the more this happens.

Interesting. So this does not pertain to CV or LTM lenses, but to any lenses that have rear elements extending deep into the camera.

 

[Xmas]

.jl.
I think the exit pupil of the symmetric lenses is nearer to the film than the exit pupil of the inverted telephoto style lenses.
Noel