1. Reminder: Please use our affiliate links to get to your favorite stores for holiday shopping!

Advice on adapting a Computar 12.5mm f/1.3

Discussion in 'Adapted Lenses' started by alex g, Jul 12, 2016.

  1. alex g

    alex g Mu-43 Top Veteran

    541
    Mar 30, 2016
    New York / Bath
    I'm afraid this is a post of the "I just got a C-mount lens and it don't fit the adapter" variety.

    Do any of you C-mount fetishists have any experience of this version of the Computar 12.5mm f/1.3? It seems to be, dare I say it, rather larger than those I've seen on this forum. Either way, the base is too wide for the Metabones adapter I have, so it looks like metal will need to be removed. After detaching the two little finger lugs from the adapter, I can get about two turns on the C-mount thread before the base of the lens base fouls on the adapter. Are there any relevant "how-to" links that anyone would care to share?

    Many thanks in advance!

    Computar 1.

    Computar 2.
     
  2. Turbofrog

    Turbofrog Mu-43 Hall of Famer

    Mar 21, 2014
    Looks like the C-mount is attached to the lens with a few screws. See if you can remove those and detach the mount from the rest of the lens. Then chuck it in a lathe and turn it down until you achieve the sufficient clearance. That's typically how that process goes...

    For example:

    before_after_1__47112.1400162313.1280.1280.
     
    Last edited: Jul 12, 2016
    • Like Like x 1
  3. alex g

    alex g Mu-43 Top Veteran

    541
    Mar 30, 2016
    New York / Bath
    Right, that's what I had imagined would be necessary. I'm just slightly nervous of removing the screws in case I can't reassemble the thing — you know how it goes, when you're looking dejectedly at a pile of parts on the table and then someone tells you that you should have removed the screws on the front first... :blush:

    I'm hoping to hear from that person beforehand this time! :)
     
  4. Turbofrog

    Turbofrog Mu-43 Hall of Famer

    Mar 21, 2014
    This may not be the same lens, but it is a 12.5mm Cosmicar (f1.4, though):

    Ben Krasnow: Adapting a Cosmicar 12.5mm f/1.4 c-mount lens to the GH1

    Looks to be a very straightforward process, the mount comes right off as you'd hope.
     
  5. alex g

    alex g Mu-43 Top Veteran

    541
    Mar 30, 2016
    New York / Bath
    Thanks for that — it does sound quite encouraging. :)

    Okay, there's only one thing for it... I'm going in! :ninja:
     
    • Like Like x 1