After realizing that I can't fit an Instax Wide back onto a Mamiya Universal Press without chopping the top, or shooting upside down, I decided to install a Mamiya Press lens mount onto an Instax Wide 300. This is not a new idea, and several others have done similar. I don't think anyone has actually installed a Mamiya Universal Press mount though. I can remove the current lens to add any of the other lenses in that lineup. Need to figure out a darkslide method. otherwise mid-pack lens changes are not possible without a changing bag. How is this done? Gut out an Instax 300, rewire the switch so that it powers the motor when holding the button down. On the front fascia of the camera toss the focusing ring and trim down one of the steps of the remaining lip, then sand the hell out of the inside until the No.3 or No.5 macro tube can slide in. Screw on the No.2 macro tube (not really a tube, this is the mount piece) and there you have it. Adjust the tube in and out to its correct position for infinity focus, I used a piece of 3 x 4 ground glass taped to the inside of a spent instax cartridge so I could adjust for infinity. Notes on the test shots: Top Left: First shot handheld at f3.5 1/30, light leak showing in the top left corner. Top Right: f3.5 1/60, the light leak is more noticeable and I found out it was because of some thin plastic that needed to be taped up. Bottom shots: Testing out infinity focus, both are at f11 1/500 I believe. I have yet to figure out a rangefinder solution, maybe an Ideal Rangefinder since they are cheap. I've had a lot of success just guessing subject distance and using the scale on the lens, alas the advantage of MF lens DOF.. f3.5 is forgiving enough to nail focus on these lenses. If anyone decides to try this at home, shave down the macro tube some as only the 90mm lens will cover the entire image area if you don't. I do intend to make a 3D printed adapter with a shorter tube section to avoid this. Currently planning on selling converted cameras eventually, or trading them for cool stuff/film/equipment. But I will definitely do my best to guide you on your own conversion.