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Thread: C-mount upside-down

  1. #1
    Gary
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    C-mount upside-down

    I just got my c-mount adapter (from Poland via ebay) and quickly attached my 50 f1.4 cosmicar (from Argentina via ebay also arrived today).

    Everything checked out fine and looks great so far. But, the lens ends up 180 degrees reversed from where I would want it - so the f-stops and focus point are not visible. Loosening the lens to put it right prevents infinity focusing. Is my adapter at fault or is this an unpredictable situation?

  2. #2
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    Re: C-mount upside-down

    It's typical of most adapters. There is one adapter that I know if that has a set screw so you can turn your lens any direction to have the aperture settings up on top. Some lenses have a set screw in the aperture ring that allows the same sort of thing.

  3. #3
    Gary
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    Re: C-mount upside-down

    Thanks for the response. I just tried loosening some of the set screws on the lens, but no good. What is the adapter that has an adjustment?

  4. #4
    thearne3
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    Re: C-mount upside-down

    Hi Gary,

    Not sure about your lens in particular, but from the picture, it appears that there are one or more set screws in the mounting flange. Loosening these may allow you to rotate the lens relative to the flange and retighten.

    I'm certain that there are others with Cosmicar lenses that can give more advice.

    Check the c-mount lens sticky at the top of the this forum - it lists all the various adapters. The ebay listings will tell you if they have the required set screw. I think it's the Hawkpen (sp?) one.

    Good luck - nice looking lens!

    Tom

    Oops! The sticky isn't there anymore! Will have to investigate...

  5. #5
    Senior Member RichA's Avatar
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    Re: C-mount upside-down

    Quote Originally Posted by Gary View Post
    Thanks for the response. I just tried loosening some of the set screws on the lens, but no good. What is the adapter that has an adjustment?
    I wouldn't mess with the lens, I'd look for another adapter if seeing the scales matters to you. In fact, these lenses don't have click-stops so you can't set aperture from feel, but it really doesn't matter much since you can preview the DOF in the viewfinder/LCD anyway.

  6. #6
    Super Duper
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    Re: C-mount upside-down

    Most c-mount lenses can be rotated by loosening screws on the mount.

    The c-mount to micro 4/3 adapter that has a rotating mount is made by MS Optical out of Japan. I am not aware of any of the cheaper Chinese adapters having this feature.

  7. #7
    Gary
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    Re: C-mount upside-down

    Quote Originally Posted by RichA View Post
    I wouldn't mess with the lens, I'd look for another adapter if seeing the scales matters to you. In fact, these lenses don't have click-stops so you can't set aperture from feel, but it really doesn't matter much since you can preview the DOF in the viewfinder/LCD anyway.
    Actually, this one does have click stops, perhaps the newer versions don't. I would like to find the MS Optical adapter - does anyone have a retailer for it?

  8. #8
    Super Duper
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    Re: C-mount upside-down

    http://bit.ly/6jn1Rv

    I think I have a spare if you need one.

  9. #9
    Senior Member Y.B.Hudson III's Avatar
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    Re: C-mount upside-down

    some c-mount lenses have retaining caps (Like those on "Ball" home canning jars). Unscrew the cap and the c-mount is oriented by a retaining pin.

  10. #10
    Member hodad66's Avatar
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    Re: C-mount upside-down

    http://hodad66.com Sony A7r,A7II, Sony 70-300G, Rokinon 14/2.8, Leitz Wetzler 35/3.5, Leica R Summicron 50/2 & Elmarit 90mm/2.8, Contax N 24-85 & 70--200mm AND Canon FD 20/2.8, 135/2, 500mm 4.5, Minolta 35/1.8, 45mm/2, Nikon 28-50/3.5, 105/1.8, 180/2.8

  11. #11
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    Re: C-mount upside-down

    Most of the CCTV lenses like the one you have will not be able to adjust, because aperture and focusing is set once and never needs to be adjusted again. So you need an adjustable adapter. (I personally had bad experience with quality of the adapter that I had, I think it was spinning on me when tightening the lens)

    The other option is to sell your CCTV lens and buy Cine lens instead. All of them have adjustable mounts, so no problem exists (at least no problems with Kern, Angenieux, Cooke, Kinoptik) but of course we are talking substantially more expensive purchase.

  12. #12
    Gary
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    Re: C-mount upside-down

    I played with the screws and was able to move everything about 130 degrees. So still not on top but usable. I see this lens as a stop-gap until I decide and can afford to buy the 45mm Elmarit. So this less expensive glass and my current adapter will have to do.

    My experience thus far is that it is soft at 1.4 and sharpens and gains contrast up through 5.6 and is good till 16 when things deteriorate a bit. I guess that is pretty much the expected behavior with less expensive/older glass.

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