Lomograflok (Instax Wide Film Back) Adapter for BH2 Polaroid Horn

Background:
A long time ago in a galaxy not far away, instant film played an important role for professional microscopists. Before the instantaneous feedback of digital, it was instant film that allowed microscopists to quickly transcribe their subjects into a shareable medium. If you needed quick turnaround on a pathology sample - project it on Polaroid and just walk in back to the doctor in only a couple minutes. Or, maybe you're dialing in a system for photographing on 35mm or larger and need to ensure that your projected image plane is coincident with a film plane. Instant film lets you do that without waiting for darkroom turnaround. Because of its pre-digital utility, very many microscope systems from the 80s and earlier included adapters for instant film. Regrettably, every last one of the formats that the hardware was designed for has been discontinued.

This part:
This is an adapter that allows a Lomograflok Instax Wide film back to seat into the polaroid adapter for the BH2 (and other Olympus microscopes). The Lomograflok is designed in a similar spirit as above - primarily for dialing in large format cameras without wasting precious and expensive large format film. All it does is hold a film pack and eject when you press a button - no shutter system or optics. This adapter slides into the mounting grooves on the Lomo body snugly and is pretty much light tight as printed. The side that connects to the Polaroid horn has similar geometry to the original polaroid film back and locks in via the same system on the horn.

Notes
I don't have an exact measurement on the distance to the film plane versus what is "objectively correct" - all I can say is this is pretty close and well within the adjustable range of a photo adapter. I dial in my focus by shooting a couple frames of a micrometer grid slide until it's sharp.

For shooting, I use a 100W halogen BHS base, a PM10-ADS, and an original Olympus exposure control unit. Set for large format and ISO 800 for Instax Wide and the auto-exposure will be pretty close. Exposure times aren't too bad - even at quite low light settings - I don't think I've ever gone over a minute and usually it's less than a second. Anything living generally will come out blurry - you'll want to get a flash system for that. But this works fantastic for diatom slides, crystals, etc. And the Instax film is surprisingly capable of replicating fine detail - some of my images have features only visible when viewing the film with a strong magnifying glass.

Printing:
I used PETG-CF for strength and opacity. Print vertically as in the STL and use painted tree supports on the overhangs - took my printer about 2 hours.

Shoot some film - it's fun!