Old Camera, New Holders

[wfwhitaker]

As a few of you already know, I'm in the process of restoring an old Eastman 7x11 camera. It has a couple of decent old film holders with it. To supplement them I purchased some new ones as well. Contrary to expectations, the new holders have a greater distance between the face of the holder and the film plane (T-dimension). My first thought was to make a new ground glass carrier which would match the holders. I can do it and I do have some nice quarter-sawn mahogany on hand, but it's a lot of work. Then today another thought crossed my mind...

Suppose if, instead of replacing the ground glass carrier, I kept the original, but made a spacer which has the outside dimension of a film holder and has a rectangular cutout to match the format. The spacer (being a specified thickness) would offset the ground glass the difference between the two carriers and provide accurate focusing/composition for the new holders (which have the greater T-dimension).

The advantages seem obvious:

1.) I would be able to use both new and old holders, increasing my useful number of holders,

2.) the old Eastman would remain original.

Disadvantages:

1.) Another piece to add to the kit, adding complexity.

Further thoughts:

The spacer frame could be machined from HDPE or Delrin. (The machining is not an issue.) Either material would be lightweight, resistant to damage and easily slide into/out of the back.

The spacer could double as a frame viewer composition aid.

Have I missed anything? What are your thoughts?

 

[rbarker]

If I understand you correctly, Will, I think the delta T is in the wrong direction to work with the GG in its current position. Yes? No?

 

[John Kasaian]

Will,
Check out www.equinoxphotographic.com I think they have a bunch of plate holders and some might be the size you're after. They could have the septums you'd need for film too. Nice folks, very resonable prices.

 

[Annie]

Very clever indeed...... I intend to steal this idea for some old modified plate holders I have
....... until now I have just been using the cross your fingers and give the rear gear a wee crank
method.

 

[wfwhitaker]

If I understand you correctly, Will, I think the delta T is in the wrong direction to work with the GG in its current position. Yes? No?

Ralph,

The ground glass is set correctly for the original holders. The T-dimension of the new holders is greater than that of the original holders so that the film occupies a plane significantly further from the lens than the ground glass.

Annie,

Steal away! Too bad the idea is so camera/holder-specific that it has no commercial viability. Besides, with a market of six people, I'd starve!

 

[rbarker]

Ralph,

The ground glass is set correctly for the original holders. The T-dimension of the new holders is greater than that of the original holders so that the film occupies a plane significantly further from the lens than the ground glass.

OK, I think I understood you correctly. Thus, I think I'm correct in saying that using a spacer in conjunction with the new holders (e.g. inserting them both at the same time) would only make the problem worse. You could, however, use the spacer alone with the GG when focusing, thus adjusting the placement of the GG to where the film plane is in the new holders, then remove the spacer and insert the new holders. Focusing without the spacer would still work with the old holders. As long as the spacer was made from an opaque material, and is sufficiently durable, it should work nicely.

 

[sanking]

As a few of you already know, I'm in the process of restoring an old Eastman 7x11 camera. It has a couple of decent old film holders with it. To supplement them I purchased some new ones as well. Contrary to expectations, the new holders have a greater distance between the face of the holder and the film plane (T-dimension).
The spacer frame could be machined from HDPE or Delrin. (The machining is not an issue.) Either material would be lightweight, resistant to damage and easily slide into/out of the back.

Have I missed anything? What are your thoughts?

I have a similar situation with some 6.5X8.5" holders. In my case the difference between T-dimension was rather small, on the order of 1mm or less, and I resolved the issue by attaching a strip of adhesive felt around all four sides of the holders that had the smallest T-dimension. This served to effectively equal the T-dimension on the two types of holders without the use of any other adaptor. It works very well in practice and if you can solve your problem in this way it is worth considering.

Sandy King

 

[wfwhitaker]

...In my case the difference between T-dimension was rather small, on the order of 1mm or less...

Sandy,

Simplicity is indeed a virtue and I appreciate your suggestion. The difference in the T-dimensions of my holders is more on the order of 4mm, however I've not yet measured it critically.

 

[grahamp]

That sounds like the most logical approach - try to (reversibly?) modify the older holders and the GG to match the newer, deeper holders. Then you only have one dimension, and no special arrangements to track. Granted you have to work on the older holders and the GG frame, which is several more units than a single spacer. There may be sound reasons why you can't take this approach - I've not looked at the camera.

 

[jimgalli]

I think the spacer idea is sound. Most of the time it will just live inside the back of the camera out of harms way. I always hate to give Murphy any more chances.....but at the price of holders, I think I could live with it.

 

[k_jupiter]

OK, I think I understood you correctly. Thus, I think I'm correct in saying that using a spacer in conjunction with the new holders (e.g. inserting them both at the same time) would only make the problem worse. You could, however, use the spacer alone with the GG when focusing, thus adjusting the placement of the GG to where the film plane is in the new holders, then remove the spacer and insert the new holders. Focusing without the spacer would still work with the old holders. As long as the spacer was made from an opaque material, and is sufficiently durable, it should work nicely.

Yes Ralph, that's what I got out of it. The spacer is for the GG when there is no film holder in it.

How come you and I haven't run into one another in our travels?

tim in san jose