The type 620 film format – long since discontinued – was mainly used by Kodak, but also by quite a lot of other camera manufacturers since its introducion in the ’30s. That is also case with my M.I.O.M Photax IV F, a French ‘art deco‘ bakelite camera from the early ’50s.
Fortunately there’s still an easy-ish way to use these classic cameras, although the original film format is not available. The film on type 120 rolls is exactly the same, the only difference between 620 and 120 is the spool, which is smaller and slightly shorter on 620. There are two ways around this:
- Re-spooling the 120 film to a 620 spool (manually in the darkroom or changing bag… ouch.)
- Modifying the 120 spool to fit in the place of 620
I chose to use the latter approach. Usually this means cutting down the end flanges to 620 size (120: ⌀25mm, 620: ⌀23mm) and filing down the flange outer ends to as thin as possible (620 spool is about 1,5mm shorter). However, Photax needed a bit different way of modification.
First, there was no need to shorten the spool, there was plenty of room lengthwise. The main problem was that the spool of the Rollei RPX film I was going to use has very large cross-cuttings at the ends (see the photo below). That didn’t play nicely with the tiny, ⌀3,5mm spool locating tabs of the Photax; the spool was constantly jamming on the cross-cuttings when I tried to roll it manually inside the film chamber. I was forced to make separate bearing inserts for the spool ends from a short length of 6x1mm aluminium tube. That allowed the modified spool to roll like a genuine 620.
From left to right: an original 620 spool, the prototype modified spool, and an original 120 spool (Rollei). On the right the actual modified film roll about to be installed inside the Photax.
