Converting Contax 645 MFB-1B 220 film insert for use with 120

Discussion in 'Medium Format' started by paley_fairman, Dec 6, 2020.

  1. Looking for info on converting a Contax 645 MFB-1B film magazine insert (for 220 film) to use with 120 film.
    I have the 220 Magazine and it will shoot with 120 film in it but does not rewind after 16 images. I've seen anecdotes about "converting" the 220 magazines to use w/ 120 film, but haven't found any more info on how it's done or if it solves the rewind issue. Seeing as these cameras are no longer made I hate to toss the 220 insert just because 220 film was discontinued. Has anyone ever successfully converted one? Thanks!
  2. I have a Omega Rapid that I bought with a 220 magazine. It can be used with 120 film if you are careful to count the exposures as you go.
    I did end up getting a 120 magazine, and it is surely more convenient.

    I have no idea what Contax 645 magazines cost on eBay or from KEH. but why not look for a 120-film one? They are certainly not common, but I'm guessing demand is not especially high either. :)

    I still have a little 220 film in the freezer and will get to it some sunny day (we'll meet again....)
  3. By the looks of things, the Contax film insert looks very similar to the Mamiya 645 film insert which is the one I own. The way I converted my Mamiya 220 film inserts to 120, was to remove this small triangular metal part on the side of the insert. You can find the instructions on how to do this on Youtube and other places on the Web. If you don't want to take any chances, you can count to 15 then put a lens-cap on the lens and take the remaining 15 pictures with the lens cap on. So far I converted 3 of my 220 Mamiya 645 film inserts to 120, but I left one as is just in case 220 makes a comeback.
  4. Hey paley did you ever work out how to convert the back? I would love to know. I accidentally bought a 220 back. I’ve did just see someone selling a converted 220 back on eBay. So it must be possible.


  5. The clue will be in the camera. There must be a switch or sensor of some sort to 'tell' the camera that a different insert is in use. It shouldn't be too hard to spot.

    There'll be a corresponding tab or notch on the insert that needs removing or filling in. Simple mechanics.

    At the most sophisticated the 'switch' might be an optical or magnetic sensor, but that's unlikely given the cost involved over a simple microswitch.

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