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Cosmicar 25mm f1.4 C-mounts NIB cheap (eBay)

Discussion in 'Hot Deals - Find a Great Deal? Share It Here.' started by ISO1600, Aug 19, 2012.

  1. ISO1600

    ISO1600 Mu-43 Regular

    27
    Aug 17, 2012
    Abilene, TX
    Chris
  2. Jonathan F/2

    Jonathan F/2 Mu-43 Hall of Famer

    Aug 10, 2011
    Los Angeles, CA
  3. madmaxmedia

    madmaxmedia Mu-43 Veteran

    335
    Feb 20, 2010
    I saw this previously (OP's link)...are we absolutely sure it's not the auto-aperture (electronically controlled) version? There's not a picture of the actual lens inside.
     
  4. ISO1600

    ISO1600 Mu-43 Regular

    27
    Aug 17, 2012
    Abilene, TX
    Chris
    Lens came in- it is NOT the auto aperture version.
    It only focuses to about a foot on my Fotodiox adapter.... :(

    will this be easy to modify?
     
  5. ISO1600

    ISO1600 Mu-43 Regular

    27
    Aug 17, 2012
    Abilene, TX
    Chris
    seeing if i can return it lol
     
  6. Zanr Zij

    Zanr Zij Mu-43 Regular

    93
    Mar 10, 2012
    Turn your lens out or in and try again. There are many adapter got focus problem. I have to use 2 plastic/rubber circle to make focus back to normal!

    Sent from my GT-I9300 using OM-D E-M5 + Leica 25/f1.4 + T*
     
  7. Mellow

    Mellow Mu-43 All-Pro

    Aug 27, 2010
    Florida or Idaho
    Tom
    Also, I've found that some c-mounts just require a different adapter. Some are thinner than others and allow the lens to screw in deeper. I used to have four or five adapters from different vendors, and usually could find one that would work.

    Of course there are exceptions . . . my Navitar 25mm needed to be modified in order to fit and focus to infinity. For some lenses you can just unscrew the sleeve near the base and grind it down against sandpaper. Others it's more difficult.
     
  8. rtb001

    rtb001 Mu-43 Rookie

    17
    Aug 16, 2012
    Rochester NY
    Are the metallic parts of lenses that soft to be easily ground down on sandpaper?

    I had a alter 2 M39 adapters for a couple of Soviet lenses I bought on a whim for my m43 camera. The adapter came in 2 pieces that come together, an aluminum threaded ring (to fit the M39 lens) and a softer metallic housing (to go on the camera, made of brass maybe?).

    For the Industar collapsible lens I bought, I had to file a little bit of the metallic housing off where the focusing mechanism sits, since it is flush against the surface, and you have to push down a little bit to get it out of infinity focus. That took maybe 15 minutes with a manual file.

    For the Industar pancake lens, you have to bring the whole lens in towards the sensor like 2 mm or so to achieve infinity focus. So I tried to grind the aluminum threaded ring, first on sandpaper (the roughest I can buy at Homedepot) and then with a manual file. The sandpaper did very little, and even struggling with the manual file for over an hour of total filing time, I made a bunch of little jagged filing marks on the ring, but maybe only 0.3 mm of total thickness actually ground off.

    So my impression is that whatever the housing is made of is SUPER soft. But then even aluminum, not exactly the hardest metal around, was a struggle to grind down with manual tools like sandpaper and file. I don't know what older lenses are made of, but I'd guess steel shell or at least some sort of aluminum alloy?
     
  9. Mellow

    Mellow Mu-43 All-Pro

    Aug 27, 2010
    Florida or Idaho
    Tom
    Sure, assuming it's the right sandpaper! (e.g., made for metal, the black kind). Most lens parts are either brass or aluminum, and thus pretty soft.

    In my case I had to take off about 2mm, and it took maybe 15 minutes of sanding--and that included several pauses to rinse off, dry off, and check the fit. It's not the fastest process but it produces a nice smooth result that's better than filing.
     
  10. ISO1600

    ISO1600 Mu-43 Regular

    27
    Aug 17, 2012
    Abilene, TX
    Chris
    i did not want to deal with sanding/filing. I asked the seller if i could return the lens and he said no problem.

    it would take a bit of material removed to reach infinity. The farthest this thing would focus was maybe 1 foot.
     
  11. Jonathan F/2

    Jonathan F/2 Mu-43 Hall of Famer

    Aug 10, 2011
    Los Angeles, CA