135/35mm film in 120 Medium Format back

I recently acquired a Bronica GS-1 6×7 medium format camera – I’m loving medium format film, but am in a bit of a dry spot while I wait for a box of the stuff to arrive from the US.

I found an excellent post by another GS-1 owner (flickr stream) who’d managed to squeeze a 35mm roll inside a 120 back – meaning you end up with 3×7 cm panoramic images, with sprocket holes and all exposed. Image 1, 2, 3.

His method was a bid fiddly; particularly the way the canister is held. Because of the different diameters of the pen tube vs the pin in the back, there’s a lot of wobble. I reckon mine is simpler (and therefore, better?)

1. Cut a strip – the same width as 35mm film – lengthways from an A4 piece of paper.

2. Cut the end of the 35mm roll off cleanly, and tape the paper to it. Mark the side of the paper that has the emulsion, then roll the film back up so just the tip of the paper is poking out.

3. Using bits of foam, jam that thing inside the 120 back. I compressed the foam quite a bit, so it was pretty sturdy – though it doesn’t look it.

4. Wind the film as normal, only winding enough paper around the take-up spool to ensure that it’s “grabbed” it.

5. Jam that thing closed. I used an extra bit of foam to make doubly sure the 35mm roll wouldn’t move; as you can see, i had to jam it in with my thumb whilst closing the film back.

6. Load the camera as normal (on a normal 120 roll, there is about 30cm of paper leader, which the camera will wind up ready for the first frame).

7. I used some black card to make a guide for the viewfinder.

Pictures should be forthcoming!

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  • john

    This is a very clever idea and improvisation excellent. The only sticking point is finding a darkroom or bag to rewind the film.

    Excellent work.

    • Jeremy

      Well, thanks. I don’t know if it was an original idea though, I may have heard about it from somewhere.

      I develop (or try to develop) a fair bit of B+W film so a darkbag is usually close at hand! Most of my friends who muck around with film also have either a darkroom or a darkbag.

      Mind if I ask how it was you found this blog? As you can see I don’t update it much, but it’s intriguing to see some traffic.

  • I have a kit for my Pentax 67 that does the same thing. I’m trying right now in my GS-1. If it works I let you konw in your flickr account. Thanks for the idea!

  • Olivier

    Thanks for the tutorial.
    Being not so clever with my hands I still hesitate.
    I read somewhere that using a 220 magazine was better.

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