Cutting Mamiya 7 panoramic adapter mask for 70mm width?

Discussion in 'Medium Format' started by toni_nikkanen, Feb 23, 2009.

  1. I was wondering if there was any problem in cutting the panoramic adapter mask to allow 70mm image width? I don't understand why the camera can take 70mm wide images on 120 film but on 135 film you mask it for 65mm width.
     
  2. Actually 6x7 isn't 60mm x 70mm... it's 56mm x 65mm. That's probably why.
     
  3. Well, 6x7 frames shot by my Mamiya 7 are about 5 millimeters wider than panoramic shots on 135 film. So I'm still wondering if there's a good reason for the mask to cut those 5 millimeters. Maybe I'll experiment myself by shooting completely without the mask and see what kind of horror ensues :)
     
  4. Paul, on the Mamya 7 the frame is actually 56 X 69,5 mm.
     
  5. Although I don't use a Mamiya 7 myself, I think that the biggest risk with leaving the mask out is that film flatness might be poorer. Thus you might loose the small benefit of slightly more film area.
     
  6. Oskar, I think you're right about that. However that doesn't explain the 65mm width. I'm very close to scissoring the extra 5mm away if someone doesn't convince me otherwise :)
     
  7. Maybe so they can fit the film into 6x6 slide mounts for projection, just a guess.
     
  8. Hi Toni,
    I don’t have the panoramic adapter so can only suggest that before you trim/expand the frame size of the mask it might be worth while checking the spacing between frames on the film. You will need at least the extra width you are proposing to expand the frame size by plus some small margin which would appear to be 1.4 mm, other wise the gearing of the film drive system will overlap the frames !!
    Best Regards
    Rob
     
  9. Rob, I don't think the frame spacing is going to be a problem. The camera doesn't even _know_ it's using 135 film; film transport-wise, it thinks it's using 220 film. This means that with the panoramic adapter, the frame spacing is 5 millimeters wider than with medium format film - so if I lose that, I'm back to the normal spacing.
    I'm also not quite convinced about the projection, as the extra 5 millimeters certainly won't _hurt_, they'll just be masked away by the slide frame instead of the in-camera mask - and the viewfinder certainly doesn't suggest narrowed width for panoramics either.
    There's gotta be a reason for all this, even if it's a silly historic one instead of technical, but I still haven't heard a convincing story :)
     
  10. Hi Toni,
    Don’t have any 220 that’s been through the M 7 but I have checked a couple of 120s. Humm they vary from 7.8 mm gap down to a lean 5mm. At 5 mm gap the end of one frame would be very close to colliding with if not overlapping the next.
    Another thing, I have not actually held one of these masks in my hand but I suspect that reshaping one might require some very delicate filing with a very fine very good file and the mask firmly held in a really good clamp/vice to prevent distortion/stretching of the mask.
    Anyway what you decide let us known how you get on.
    Best Regards
    Rob
     
  11. I have shot several rolls of 35mm in the 7ii without the pano mask in place and it never caused a noticable problem. Frame overlap is not an issue.
     
  12. I'll try to post an example scan. The gap is narrow, perhaps 3mm-5mm.... but out of 8 rolls I shot no overlaps.
    Rob is definately right about the mask being flimsy... the previous owner of my camera closed the back with it slightly misaligned, and it is now ruined. To look at it you would think it would still work fine, but the tiny distortion in it won't allow the film to advance when it's fitted.
     
  13. Hi Chris,
    Excellent, success, we live and learn.
    Best Regards

    Rob
     

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