Iso on Mamiya M645?

I just bought this camera. I took it out to shoot and noticed there wasnt an Iso dial. I dont have an iso/metered viewfinder either.  I used a light meter app. The camera was loaded with the typical portra 400. Im just wondering if my photos will be exposed because there is no iso setup?  Or will it just be a black frame? I manually entered my iso as 400 in the light meter app and in return it gave me an aperture and shutter speed. Im sending it off to a developer here shortly. Thanks for any and all responses.

4 Answers

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  • Anonymous
    1 month ago

    The basic workings of any camera do not 'need' ISO. Those basic workings are lens aperture (f-numbers) and shutter speeds. 

    If the camera has a built-in meter which is in working condition (battery good?) then indeed you need to enter the ISO onto the meter if you want to use that meter to help you set the exposure level correctly.

    So you should use your light meter app (Gosh, is there anything which smartphones cannot do these days?!) and set aperture and shutter speed according to what the app says.  Did you do that?

    Typical outdoor values for 400 ISO are f11 at 1/500 on a bright sunny day. On a cloudy day maybe f5.6 at 1/125, but very variable, which is why we use meters or meter apps.  Were your settings somewhere in those regions? If so you should get at least some useable negatives.

    Nice cameras those Mamiya 645s. Don't bother with the motor drive - very slow in my experience.  The 45mm f2.8 wide-angle lens is really good, really sharp, better than the Hasselblad lens of 50mm.

  • keerok
    Lv 7
    1 month ago

    It will be exposed correctly if you followed the light meter. You'll do fine.

  • Anonymous
    1 month ago

    The ISO dial would be located on the AE viewfinder itself. Without an ISO dial or built in light meter, you need to remember the ISO of the film you use and then set the shutter speed and lens aperture manually according to an external light meter. If you set your shutter speed and lens aperture correctly and the camera and lens are working properly, then you should get correctly exposed film.

  • Sumi
    Lv 7
    1 month ago

    If you used an external light meter with it set to the proper ISO/ASA, then your exposure settings are correct.  The fact that there isn't an ISO/ASA dial on your M645, or even if it does have one and it's set to an incorrect ISO/ASA setting, your exposures will still be accurate (providing your hand-held meter is working properly and you used it properly).  I have an RZ67 and typically use a hand-held light meter instead of the built-in meter.

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