If it's already been answered elsewhere, my apologies, but I haven't found it yet...

Is the film plane set back from the surface by the same amount in all the Graflex/Graphic/GrafMatic film holders?

In particular:

1) If I wanted to try something foolish like coming up with a frame to mount a smaller holder into a larger camera, does it have any chance of success?

b) If I wanted to try something foolish like cutting down and carving a slot in a 4x5 Graphic film holder to mount it on the 3x4 Graflex back, does that have any chance of success?

(The first is more attractive to me -- it doesn't require irreversable modification of the holder -- but getting a decent light seal might be Interesting.)

Yeah, I know, just get a 4x5 or 2x3 camera, selling off this one to pay for it... but this one's grandpa's.

1.The film plane of 2x3, 3x4, and 4x5 film holders is .197 ± .007 inch from the edge of the holder. Sheet film is .007 inch thick.
Roll film holders should be the same.
b. The frame of a 4x5 film holder, grafmatic, roll film holder cannot be cut down to fit a 3x4 camera.
A piece of plywood, ABS plastic, or acrylic can be formed to fit a 3x4 Graphic or Graflex back on one side and the 4x5 holder image plane center mounted on the other.

Re (b)... I can see, I think, how to fit a complete 2x3 film holder into a cutout in a 3x4 (or larger) slotted panel and align it with the inner face so the film plane winds up correctly positioned, especially if I don't insist on having a dark slide. But unless I'm misreading it, your wording suggests it's possible to fit a 4x5 holder to a 3x4 camera's mount, and I'm having trouble visualizing how that could work.

FWIW, I seem to have gotten the 120 roll extenders to work with the old #51 roll film pack. Friction was a bit high initially, but applying some thin teflon tape to the surfaces the backing paper slides against seems to have solved that problem. A similar bit of adaptation might be needed to help keep the film flat, though if I engage the latch and tension it that seems to bring it close enough to flat for initial testing purposes. And of course I'd be advancing film by approximation and rule of thumb so there's going to be a bit of wastage between frames. "Real" 120 on order (as opposed to the outdated stuff I was using for mechanical test/practice), so I'll soon be able to do some more serious testing.

Which back do you have on the camera?

Camera has 3.25x4.25 Graflex back).

I have a #51 roll film holder (with, as I say, some adaptation which I think will let me sorta run 120 through it), and a 3.25x4.25 bag mag waiting for when I'm ready to start trying to shoot and develop sheet film.

I'm pondering whether there's a way to get a "proper" 120 roll holder onto it without shelling out paying the $175 I've seen this size going for on eBay when they're available. Not that I can't afford it, I'm just not ready to make that investment.

Take a piece of 1/4 inch thick piece of material. Mark and cut the light tight grove for the holder to sit into. Make clamps to fit onto the edge of the holder and attach to the adapter piece.
Mark the dimension of the holder on the adapter. Mark the image area by subtracting the edge widths. Find center and mark the 3 1/4 x 4 1/4 image opening in the center of the 4x5 image opening. Cut the 3x4 image frame out. Center the 3x4 cutout to the camera image opening. Mark the outside of the Graflex frame on the camera side of the adapter. Using a veining bit in a router or Dremel cut a grove in the adapter so that it just fits into the Graflex back. EDIT: Remove the Graflex mount bars then screw the adapter to the back with #1 wood screws 3/8 inch to 7/16 inch long using the mount bar screw holes.
Adjust the view finder ground glass to the new film plane.
The adapter will be thin in places. The viewfinder ground glass will just adjust to the new film plane.

Been there, done it.

keshlam wrote:

Camera has 3.25x4.25 Graflex back). I have a #51 roll film holder (with, as I say, some adaptation which I think will let me sorta run 120 through it), and a 3.25x4.25 bag mag waiting for when I'm ready to start trying to shoot and develop sheet film. I'm pondering whether there's a way to get a "proper" 120 roll holder onto it without shelling out paying the $175 I've seen this size going for on eBay when they're available. Not that I can't afford it, I'm just not ready to make that investment.

The Adapt-A-Roll 620 is an insertion type roll holder with a 2 1/4 x 3 1/4 gate. It was made in sizes to fit 2x3, 3x4 and 4x5 spring backs. It can also be inserted into Graflok backs. It was made for 620 film, must take film up on a 620 spool but can feed from a 120 roll. 3x4ers are uncommon but with patience you should be able to find an inexpensive one.

Unfortunately, my RB-Auto box is neither Graphic nor Graflok. Yeah, I know, it could be adapted. Not sure I want to do that, at least not yet.

45PSS: I _think_ I'm following, but a photo or two would help.

I'm (unreasonably?) reluctant to modify the camera itself, hence my brainstorming about the approach of a homebrew 3x4 plate with cutout for a 2x3 filmholder.

A 2x3 on a 3x4 will be easier than a 4x5 on a 3x4.
I made an adapter for another person and I do not have a 3x4 camera.

With regards to the film depth in different film holders, the 4x5 holders for Graflex backs appear to be slightly deeper. I submitted the following post on this subject back in 2012:

"The Graflex holders are deeper than standard 4x5 holders. I measured all 4 corners of both sides of two of my Graflex holders, and the following are the results as average and range: 0.226" +/- 0.002" ; 0.224" +/- 0.002" ; 0.221" +/- 0.002" ; 0.224" +/- 0.002" . The overall average and range for these four sides is 0.224" +/- 0.005", or 5.69 mm. This is a remarkable degree of precision for wooden film holders (I've never seen plastic Graflex holders - were they ever made?). These measurements were made with film in place - to the film plane, in other words - using a depth gauge which spanned the corner. (Film thickness 0.008").

By comparison, the ANSI standard for 4x5 holders is 0.197" +/- 0.007". The Graflex holders are therefore deeper by about 0.027" - nearly 1/32". If you want to use a regular 4x5 ground glass back to check focussing on a Graflex, you will therefore have to shim it by this difference."

I've just inherited a 3D printer, so I may try that approach to creating the 2x3-to-3x4 adapter. If I do so, and if it works out reasonably, I'll make it generally available.

(Great. Yet _another_ pending project. How can anyone be bored in retirement?)