Identidem Design 6x7 Film Back

This is a brand new, drop-in replacement for an RB67 film back, designed by Albert / Identidem Design.

Albert has been reviving cameras (and designing new ones) for a while, and we know each other through the strange little world that is the Film & Filament Discord.

When I got such a strong reaction to my camera, it felt a bit rough to send every buyer to eBay — not just for a lens (or lenses), but also for a film back from a dwindling stock.

I can't solve the lens problem (yet), but I figured there had to be a way to make the back situation better. I'd already been chatting with Albert about his MRF design, which neatly sidesteps one of the big headaches in medium format: frame counting.

Unlike 35mm, 120 film has no sprockets, so counting movement isn't straightforward — historically it's been a grab-bag of clever mechanical hacks to measure the passage of a slippery strip of plastic and paper. You can dodge all of that with a red window if you're shooting 645, 6x6, 6x9 (or multiples thereof) — but 6x7 has no real get-out-of-jail-free card.

Albert's approach uses an electronic rotary encoder to measure take-up spool rotation. Then it applies a bit of maths to compensate for the spool getting “fatter” as film winds on. The result is frame spacing that's accurate and repeatable.

It also unlocks some fun flexibility: want to drop in masks and run 6x6 or 645 using the same back? No problem.

In this version, the screen also doubles as a very accurate digital level (thanks to a small extra chip on the board). I expect that to be genuinely handy at night, when bubble levels can be hard to read.

There are a few other nice quality-of-life tricks too — like the back knowing whether the darkslide is in, and warning you before you do something silly (like winding on without taking a shot because you forgot to pull it).

The one obvious downside is that it's battery-dependent. It takes common CR123A cells, and USB-C rechargeable versions are now a thing (the USB-C port is on the side of the battery). It's still in the prototype phase so there’s no formal test data yet, but early indications are that battery life will be pretty generous.