Back in the late 1990s as the digital ... for 35mm film cameras. Imagine a film cartridge with attached sensor, the idea went, which you could just drop into your trusty SLR and continue shooting ...

Make a film cartridge out of a Raspberry Pi that can convert your camera to digital. (Video ... but don’t forget that the way an SLR works means if the shutter is open, there’s no viewfinder.