For decades it was commonplace for professional 4x5 shooters to take proofs on 4x5 Polaroid film. While in today's market being able to use instant film on a large format camera doesn't have the widest appeal, for those that it does appeal to it's kind of a big deal. Being able to test shots without wasting time, chemicals, or precious sheets of expensive 4x5 film is invaluable to a large format photographer that needs or wants visual feedback. In the past 20 years expired 4x5 polaroid has gotten older and more expensive, so this practice has largely gone away. Thankfully with Lomography's introduction of the Lomograflok Instant Back large format photographers now have an affordable way to use their 4x5 cameras for instant photography once again.
The back uses four AA batteries and Fuji's Instax Wide film which is both inexpensive and widely available. While it won't cover a full 4x5 frame you still get a decently sized photo on one of the most attractive instant stocks on the market. The kit comes with a frame mask and back adjuster that shifts your focal plane to match the film back's. Once you've composed your shot you remove the mask and your ground glass and set the film back against your 4x5 body and slide the holder rails in. After that just remove the dark slide, make your exposure, and hit the eject button. It's the most elegant solution I could imagine given the limitations and inherent bulkiness of shooting integral film and once you're in the swing of things it's a great system considering its modest price tag.
The textured plastic does seem like it's going to accrue scuffs over time, especially the mask that you slide behind your ground glass for composition, but overall build quality feels solid and I'm not overly worried about the plastic breaking, just taking some cosmetic licks. My biggest complaint is the eject button being pretty easy to press by mistake, but even that's a problem that's very easy to work around if you're diligent about turning the back off when not in use. All in all given the experience of my first time out it's a great piece of kit for those who want to shoot widely available instant film on a large format camera, especially for the $150 price tag.