This instructable is about building your own adapter to mount your mirrorless camera in place of film.
This isn't the first digital sensor mount I've made for a large-format camera; in http://aggregate.org/DIT/4X5/ I describe how I packaged the sensor from a cheap webcam so it could be used in place of a 4x5 film holder. It was way back in the late 1970s that I built a back to mount my Minolta SRT101 film SLR on the very same 4x5 camera. In fact, on eBay for between $150 and $200, there are now various sellers offering similar backs with the additional feature that you can slide your DSLR horizontally in order to create stitched panoramas. They don't seem to come with mounts for mirrorless cameras, but you can always just stick an adapter on the DSLR mount to convert it to your mirrorless mount. Sounds pretty good, right? So why build your own?
Well, first off, the unit described in this instructable costs more like $10 to build. No, the digital camera can't slide for panoramas -- but that's ok, because most large format cameras allow the lens and/or the entire back to do that, giving exactly the same functionality! In fact, the lens can shift in both the horizontal and vertical directions, giving better functionality. However, the primary motivation is more subtle and more important: the mounts of necessity force a DSLR to be quite far behind the original film plane (unless you can push your DSLR partly inside the open back of the camera, as in http://www.thingiverse.com/thing:18989), making it impossible to reach infinity focus with some lenses. The shorter flange distance on mirrorless cameras, combined with the lack of front-facing protrusions, allows them to come much closer to aligning with the intended film plane of the large format camera... so infinity focus is much more likely to be feasible and lens tilt and shift features are less likely to be impeded by mechanical obstructions.
Step 1: Stuff You'll Need
- A mirrorless camera (which should not be harmed by any of this)
- A large-format camera (which should not be harmed by any of this)
- A cheap extension tube set -- the kind with front, back, and three screw-threaded in-between segments
- Any tools required for removing the large-format back (typically a screwdriver)
- Material for the board; probably either scant board or plywood
- A saw and sandpaper to cut and finish the board to size
- An adjustable hole saw or other device that can make a hole in the board
- Paint and brush or other finishing materials
- Glue for setting the extension tube in the board hole
- Electrical tape or other light-sealing material (e.g., black paint)
- Thin metal/plastic and craft foam to make flat springs to hold the back in place
There is a good chance you have pretty much all the above -- except the extension tube set. You can get that on eBay for less than $7 shipped. They're made in China, but you can get them shipped from within the US for about $0.50 more.