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  1. #1
    wiseowl's Avatar
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    Question for those with S.A 90 F8

    I have a super angulon 90 f8 in a synchro compur, I've noticed that the f stop lever moves across 2 more clicks than the f8 mark when fully open, ie to the f5.6 position if it was marked. At one click (f6.8, if it was marked.) down I can start to see the blades and when it is on the f8 mark the aperture blades are clearly visible. The aperture lever does move all the way around to minumum aperture, (f45)

    Is this normal for this lens, or are the aperture marks one stop out? if they are how do I adjust the aperture lever?

    Thanks

    Martin
    I'm Spartacus!

  2. #2
    Ole
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    Mine is in a Compur #00, so I can barely see the aperture scale!

    But no, mine is fully open at f:8. Could you be missing the little angled pointer on the aperture lever? Many of these small WA lenses had an "offset" aperture pointer, it looks like exactly the same scale was used for 90/8 and 121/8, with a different pointer!
    -- Ole Tjugen, Luddite Elitist
    Norway

  3. #3
    David H. Bebbington's Avatar
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    You should not worry, the marked f8 will be right. The aperture control caters for all the possible lenses that could be mounted in the same #0 shutter, and the lens groups of a 90 f8 SA have a comparatively small diameter on the inside faces, so opening the aperture past a marked f8 will have no effect.

    Regards,

    David

  4. #4
    wiseowl's Avatar
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    Quote Originally Posted by David H. Bebbington
    You should not worry, the marked f8 will be right. The aperture control caters for all the possible lenses that could be mounted in the same #0 shutter, and the lens groups of a 90 f8 SA have a comparatively small diameter on the inside faces, so opening the aperture past a marked f8 will have no effect.

    Regards,

    David
    David, I follow what your saying but at the f8 mark, the lens is apparently stopped down?

    Thanks for the replies

    Martin
    I'm Spartacus!

  5. #5
    wiseowl's Avatar
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    Quote Originally Posted by Ole
    Mine is in a Compur #00, so I can barely see the aperture scale!

    But no, mine is fully open at f:8. Could you be missing the little angled pointer on the aperture lever? Many of these small WA lenses had an "offset" aperture pointer, it looks like exactly the same scale was used for 90/8 and 121/8, with a different pointer!
    Ole,

    the pointer is a molded plastic knob, not a small angled pointer. There doesn't appear to be any distortion or damage to this.

    Thanks

    Martin
    I'm Spartacus!

  6. #6

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    Quote Originally Posted by wiseowl
    I have a super angulon 90 f8 in a synchro compur, I've noticed that the f stop lever moves across 2 more clicks than the f8 mark when fully open, ie to the f5.6 position if it was marked. At one click (f6.8, if it was marked.) down I can start to see the blades and when it is on the f8 mark the aperture blades are clearly visible. The aperture lever does move all the way around to minumum aperture, (f45)

    Is this normal for this lens, or are the aperture marks one stop out? if they are how do I adjust the aperture lever?

    Thanks

    Martin
    Mine is mounted in a 0 copal. Your lens aperture will be accurate at the Fstop indicated.

    The shutter will be capable, in many cases, of exceeding the advertised and marked Fstops of a given lens. If you wish to use the smaller or larger F stops accurately, you should measure the apparent pupil diameter and compute it against the focal length of the lens.
    Art is a step from what is obvious and well-known toward what is arcane and concealed.

    Visit my website at http://www.donaldmillerphotography.com

  7. #7
    Paul Sorensen's Avatar
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    I have one also in a Synchro Compur. My aperture have positive click stops and it does not go beyond f/8 at all, however, at f/8 the aperture blades are clearly visible.

  8. #8
    Ole
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    My 121mm f:8 Super-Angulon is mounted in a Synchro Compur 0 which obviously was intended for a different lens. At f:5.6 (largest opening), the aperture blades are clearly visible. I estimate it as "marked 5.6 = f:10", and expose accordingly. So far even slides have been spot on.

    I repeat: At f:8 setting, the aperture blades on my 90mm f:8 SA, in Synchro Compur 00 shutter, are almost but not quite visible.

    I recommend that you take a few comparison shots with your 90mm and another lens at the same aperture and speed (if the speeds are to be trusted, or can be measured or be made long enough to be timed by a wristwatch). From what you've described, I would not trust it.
    -- Ole Tjugen, Luddite Elitist
    Norway

  9. #9

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    There is a way that is a lot quicker and less expensive to determine the validity of the actual Fstops and their corresponding designations.

    At F8 a 90 mm lens would have a apparent pupil size of 11.25 mm. At F32 the apparent pupil diameter would be 2.81 mm. At F45 the apparent pupil diameter would be 2 mm.

    Exposing film is a less definitive way since you have to consider the possible variable of inaccurate shutter speeds.
    Art is a step from what is obvious and well-known toward what is arcane and concealed.

    Visit my website at http://www.donaldmillerphotography.com

  10. #10
    Monophoto's Avatar
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    I have the Calumet version of the SA 90/8 in the Copal 0 shutter, and it displays the same characteristic that the aperture lever will move past the f8 position with no apparent increase in physical aperture. I suspect that this is merely a personality quirk of that shutter.
    Louie

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