Hasselblad PM45 'crops' top part of screen

Discussion in 'Medium Format' started by 10999166, Jan 17, 2021.

  1. Hi

    I just got a used PM45 for my 500CM. I seems to be in very good quality, though, it does somehow crop the top part of the screen. It seems to come from reflection of the viewfinder itseld. I'm not sure wether its normal, a screen problem or a PM45 problem.

    Anybody got similar issues?

    Thanks and best
  2. All finders, including the PM45, will crop images from lenses longer than 80 mm. 200 series cameras and newer cameras have a longer "gliding" mirror, which does not crop the image. Only the finder is affected, not the image on film.
  3. The PM45 was the final, most expensive unmetered prism, so fewer of us have direct experience with it. I don't, so can't tell you anything about its cropping or internal reflections.

    I do own several examples of the nifty, oldest NC2 45 prism, and the first LED PME 45 metered prism. These do not have any internal reflections when mounted on the camera. They do very slightly crop all four edges of the screen vs the WLF or rigid magnifying hood: perhaps 5% (not significant unless you look for it to measure it).

    You do need to factor the lens in use, however, as Ed_Ingold pointed out. The older 500c, 500cm, 503cx, 503cxi, 501c, 500el, 500elm all have mirrors that are too short, due to lens design constraints when the 500 system was developed 60+ years ago. This allows the mirror to clear the rear element of the 80mm Planar and shorter lenses, but causes slight to moderate vignetting at the top of the focus screen with longer lenses. This darkening at the top of the viewfinder becomes more visible when using the prisms, because they have more eye relief and less magnification than the WLF or rigid hoods.

    I find the vignetting insignificant with the 100mm Planar, and only slightly perceptible with the 120 Makro and 150 Sonnar at normal distance (at closest focus or with extension tubes it becomes obvious but not distracting). It really kicks in with the 250mm Sonnar: no getting around it, that one puts a distinct dark band across the top of the viewfinder that gets much worse as you focus closer. If using the Acute Matte split/grid screen, the 250mm vignetting blacks out roughly the top row of checker squares.

    Its something most Hassselblad photographers just get used to, not a big deal most of the time unless you do a lot of very precise work with the 180, 250 or longer teles (or heavy macro). Hasselblad eventually addressed the issue by fitting a larger, retracting (aka "gliding") mirror in the 501cm, 503cw, 500elx, 553elx, and 555eld. Exchanging your 500cm for one of those later bodies will totally eliminate vignetting or top-of-screen cutoff (if it bothers you). But you'll still get slight cropping all around the edges with the prism finders: thats just the nature of medium format prisms.
    Last edited: Jan 17, 2021

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