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Thread: is this super angulon 121 fully open?

  1. #1
    digging for fire
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    is this super angulon 121 fully open?

    hello.
    i have 2 questions regarding this lens.
    is the synchro compur correctly adjusted? is this lens open lile this (pic1) at f8?
    and how about the shutter blade (pic2) is this normal? its the only synchro compur i own, so i cannot compare..

    thank you

    chris

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  2. #2

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    Re: is this super angulon 121 fully open?

    chris
    Did you try a quick measurement and calc the resulting f stop?
    Some folks will chime in and say not precision, but it should get a close answer- like say it should look wide open instead.
    You could also do a quick and dirty to see how big the opening should be at f8 and compare
    regards
    Ed

  3. #3

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    Re: is this super angulon 121 fully open?

    I have and use a 5.9” f/14 No. 5 Gray Periscope lens on my 11x14. As with your lens, the aperture is half closed at the marked f/14. But the aperture can be fully opened beyond the f/14 mark for focusing purposes only (so I was told). Same thing with some other lenses that I have owned. I've made exposures with the apertures fully open and the results were poor.
    just adding in my 2 cents...

  4. #4
    Les
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    Re: is this super angulon 121 fully open?

    I've checked my 121/8 and the aperture you are showing is near F11. If you need F8, then you shouldn't even see the aperture blades. Can't compare the shutter to my Copal O. Hmmm, there might be an issue.

    Les

  5. #5

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    Re: is this super angulon 121 fully open?

    Just checked my SA 121/8 and I agree with Les, wide open (f8) you cannot see aperture blades. They only become visible as you stop down. Seems like an issue with your shutter.

    Don

  6. #6
    digging for fire
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    Re: is this super angulon 121 fully open?

    thanks for verifying!
    any ideas how to change that, in other words how to adjust the aperture setting on a synchro compur?

  7. #7

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    Re: is this super angulon 121 fully open?

    The 121mm SA was offered in a couple of different shutter mounts. Some apparently mount directly to a #0 shutter. Mine doesn't. It has a Synchro-Compur shutter in a metal shell with cutouts for levers and an oversized knurled speed ring (see attached photo). Is yours like that?

    From memory, I'd say the aperture blades are just visible when wide open but I don't have the lens with me to confirm.


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  8. #8
    digging for fire
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    Re: is this super angulon 121 fully open?

    Quote Originally Posted by ottluuk View Post
    The 121mm SA was offered in a couple of different shutter mounts. Some apparently mount directly to a #0 shutter. Mine doesn't. It has a Synchro-Compur shutter in a metal shell with cutouts for levers and an oversized knurled speed ring (see attached photo). Is yours like that?

    From memory, I'd say the aperture blades are just visible when wide open but I don't have the lens with me to confirm.


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    no, mine is a usual synchro compur.
    i am wondering how to adjust the aperture. maybe i should do some testing, leaving everything just the way i got it..

  9. #9
    Corran's Avatar
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    Re: is this super angulon 121 fully open?

    A little thought experiment. If your 121 SA has a smaller opening than it is supposed to have at f/8, then the lens focal length the shutter is marked for must be slightly shorter. 90mm f/8 lenses are very common in #0 shutters. A 90mm lens at f/8 would have an aperture size (as seen through the front element) of roughly 11.25mm. Therefore, it is reasonable to assume that at that setting, the iris opening is around that size. This would correspond to roughly f/11, or one stop of correction. It would also follow that if this is true, it is likely your shutter is a #0 size as mentioned, perhaps originally for a 90mm SA. Some Synchro-Compur shutters have removable / replaceable aperture scales - finding the correct one though for your 121 SA will probably be difficult. If it is a #0 then perhaps you should look for a good shutter with a trashed lens.

    If I were you, I would shoot a few sheets with a one-stop correction (if you want f/22, set it at f/16), and see how the negatives look. I did this for a while with one barrel lens I had that fit into another shutter I had on a different lens. I would swap the elements and mentally correct the aperture. In this case it was a 305mm lens into a 150mm lens shutter, and I corrected by 2 stops. Negatives were fine. If you are shooting chromes in exacting conditions, obviously the precision of these corrections would be problematic.
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  10. #10
    scm's Avatar
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    Re: is this super angulon 121 fully open?

    It appears from the photo that one of the aperture blades has popped out of place and is preventing the aperture assembly from opening fully.

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