Rules are made to be violated. I am happy to said that, since I break another rule I set before, it means the limits are less, options are wider.
Byron has its own back system, differs from International Standard Back System or Graflok Back System, because I want it to keep simple and slim as possible.
Since it did not follow industrial standard, there are some limits for those standard film holder to be mounted on.
I received feedback from my dear client Raymond, who are not satisfied when using regular double dark slide film holders: "The tabs holding the film holder do not close completely when a film holder is inserted. The tension is insufficient to keep the film holder snuggly against the camera and I am concerned that there will be a light leak. Is this how it is supposed to work? It seems you are trying to make the tabs work with all types of backs but have compromised the operation when used with a regular film holder. I think it should be the other way around - it should work perfectly with the film holder and compromises should be made when using the other backs."
What my main purpose on developing Byron camera is for hand-held, street snap 4x5 rangecoupled, so those holders who can carry as many films as possible are prior listed, Grafmatic 6 films, 120 roll films, instant film packs, to name a few, and they are all in Graflok standard, thus Byron Back System was guided for Graflok standard. Two clamps on both up and beneath side hold Graflok film holders very well, you can see operations on my YouTube video.
Trying to design a system perfectly fit both for Graflok and Graflex systems, but failed, so I had to compromise the regular double dark slide film holders, what clamps hold are only the tiny ditches on side of the holders, not very securely held. In the picture below you can see that clamps do not grip the holder by "bite in" the holder, but just hold the side by the tension.
For this I set the limits on regular double dark slide holders, only allow those holders who has ditches on side, like brand Fidelity series, or Lisco holders; and those holders who has no ditches on side are off the list, like TOYO holders.
Though clamps do not "bite in" the holder, I am not so worry, since when hand-held, your left hand holds the camera, thumb naturally press the back , providing good support of the holder, to keep it from falling.
But how about when not hand-holding, but on tripod, there is no hand to press the back, will it be secure to hold? That must be concerned by many clients who are experienced LF camera users, but seldom hand-held snaps on 4x5, like what Raymond said.
For this, I provide three options to clients to choose.
1. Keep It that Way.
If you use Fedelity or Lisco holders, with faint ditches on side, and would like to hand-held snaps, you don't need to do any change, just use the holders. When you mount the holders, your left hand thumb will provide enough press to keep the holder, and the dark slide you insert into the blocking plate (see pic, above), provides another security to keep it.
2. Make Ditches for Bite-In
If you are good at machine, and happen have tools, you can make ditches on side of the holders, let clamps grip the holders by "Bite-In", it is the best solution I can get now, but you need tools to do it. The ditch is 1.5mm wide, 20mm long, and 2mm in depth.
Here I use TOYO holders, whose side are without ditches, but with these ditches I made, they are feasible for Byron now, holders is securely hold.
3. The Velcro Way
I know that ditches way is difficult for average people, so there is an easy way, what we want to prepare are velcro tape, a pair of scissor, and file.
File both side of holder, to make room for velcro tape, you can compare original holder and the one who been filed.
Then cut the proper size of velcro tape (hook side), paste it on both sides of holder, now we provide very good "Bite-In" zone for clamps!
For comparing the "Bite-In", we list three ways in a row, you can choose an option you like. Now, the DD slide holders are not limited anymore, any holders allowed!!