A film holder has essentially one simple function - to hold the frame flat. Now, it may sound simple, but achieving satisfactory flatness means weighing in other factors, like ease of use, speed, cost, etc.
There are a ton of holders on the market and each tackles the balance in user-friendliness, speed, flatness, and cost differently. Let's take a look at the most common approaches and see why I designed the Lobster Holder the way I did.
The Slot Machine
This is arguably the simplest approach - you insert your film from one side, take a picture of the exposed frame, advance the film, rinse and repeat.
It is fast and can work reasonably well with 35mm. The problem with this design is that it relies on a gap that cannot be adjusted and usually is around 0.15 mm, which is roughly the width of most film stocks. However, you need to factor in manufacturing tolerances and not all film being equally thick and you inevitably get some play. You actually want some play/tolerance with this design, otherwise, you would not be able to advance your film without scratching it.
As I mentioned, it might work well with 35mm, not so much for 120. 120 film is (most of the time) a little bit thinner than 35mm (don’t ask me why) and the gap play/tolerance effect multiplies simply by the medium being much bigger than 35mm. I was getting subpar sharpness at the upper and lower parts of my scans because of that, especially when I stitched multiple frames to get as much resolution as I could.
I invest a _lot_ of money and time in my medium format photography and I want to get the most out of it, so this was a no-go for me.
The Vice
This had been the standard before DSLR scanning became so popular. You put in your negative and clamp it down either by tightening a couple of screws or locking a latch or something like that.
It does hold your film flat (if designed well, looking at you Epson) and is reasonably cheap to make, but boy is that finicky to use. You need to open it, advance the film, align the next frame, close it, realign the holder (because you most likely moved it when you were advancing frames), and take a shot. Try to do it 144 times after you come back from a vacation. You’ll throw your film camera out of a window.
The S Curve
Some holders (like the excellent offering from Negative Supply) guide the film through an S curve, which, again, keeps the frame nice and flat if done right. However, since there is no moving part that clamps your film tight, the holder needs to rely on tight tolerances and a dialed-in advance system so that you can advance your film easily, keep it flat and not scratched. This is difficult (expensive) to design and even more difficult (expensive) to manufacture.
So What
If money were not an object I would probably buy a full rig from Negative Supply and that would be it. I wasted all my savings on film and lenses though so spending $1500 on film scanning was not an option.
I tried a couple of the well-known budget options and eventually disliked all of them. They were either cumbersome to use or didn’t hold my negatives flat, which kind of defeated their purpose. One day, when lugging my RB67 and 10kg worth of lenses through a national park, an idea came up. Magnets!
I wanted a holder that can actually hold film flat, allows for fast operation, and can be 3D printed. That’s where the idea for a clamp design, holding a negative down by magnets, that can be released by pushing a button, came up.
See it in action: https://www.youtube.com/watch?v=fLRXs5X81YU
You put the film in, align, take a shot, push the button with one hand (which lifts the top plate slightly), advance the film with the other hand (sorry one-handed people, please wait for V2), release the button, and take a shot again. It is super fast and simple and I still cannot believe my neanderthal brain has actually made this and it works.
I figured I could not be the only individual in a similar position. This is why I have this e-shop and sell the holder and accessories for what I see as a reasonable price.