8 x 20 question

[kwin]

I recently was given an incomplete Korona 8 x 10. I have dreamed of having a 8 x 20 for years.
I have decided to convert the 8 x 10 to an 8 x 20.
Does any one have the dimensions of the rear " standard" the frame that accepts the rear of the bellows and the part that the ground glass back assembly attaches to?

If some one has these dimensions I would be greatly apprecitive.

Thanks

Keith

[jbenedict]

The banquet cameras frequently were not built to one particular standard so the holders built by one manufacturer will not necessarily be usable with the ground glass assembly from another manufacturer. Here's a link from S&S Film Holders which explains this:
http://ssfilmholders.com/?page=dimensions

The most complex part to make for all sheet film cameras is the film holder. The bellows and other parts are pretty straightforward. If I were approaching this project, I would find the film holder/s first and go from there. The dimensions of the ground glass frame and the back of the camera need to match the holders. Since you will be building the camera back yourself, you can make it match the holders you find.

As you can see in the S&S page, new banquet holders are quite expensive. You might need to find used ones and rebuild them to be suitable. The size of camera you build may just be determined by the size of holder you can find at a price you can afford. Obviously, one holder is necessary and hopefully it has two sides (most do). Having a second holder would be really nice so you wouldn't have to head into the darkroom (or really big changing bag) after only two shots.

[Michael Kadillak]

Directly to your question. My Canham 8x20 camera has rear external frame proportions of 23 1/4" x 12 3/4". If you have any other dimensions you need let me know.

[Len Middleton]

Keith,

If you are looking for a close relative to your 8x10, its bigger sibling in the form of my 8x20 Korona Panoramic View has rear frame /standard of about 22-3/4" x 12-1/4" constructed with 3/8" x 2-3/8" pieces, excluding the back itself.

I have two Korona holders for it and they work well, unsurprisingly...

The other consideration is having the rear extension for your 8x10 project camera so that you have some bellows extension for the bigger lenses. I have about 32" of bellows and enough rail to stretch it out fully.

New bellows from Custom Bellows UK and them mounting onto existing frames cost about 350 UKP, but they do really great work.

Hope that helps and good luck with your project,

Len

[kwin]

Thanks so much for your assistance.
I will kee you updated on the progress.

Keith

[Michael Roberts]

Keith,
Have you considered just building an 8x20 expansion back for your 8x10?

[John Jarosz]

I made my 8x20 from a couple of basket-case Kodak 2D 8x10's.

Buy an S&S filmholder and use it as template to build the rear standard. As others have said, there is no exact standard that all 8x20 holders conform to. So standardize on one holder and only acquire those. You should also get the bellows first and build around those dimensions. Making a detailed drawing of how everything interacts will really help.

[Len Middleton]

Might try a slightly different approach to what John is suggesting.

I expect that the S&S holders are nice, but I believe they are custom made so they can match whatever other holders you might have if you provide them with one to match. Given the price, it might make more sense to purchase some used existing holders that match (just don't try to buy the 8x20 Korona ones and drive the price up on me...:D), then supplement it with the S&S ones as required.

The back can then be built to match the holders, ensuring the overall dimensions of the back are sufficiently large for the structural and functional needs of the rear frame, bearing in mind the rear frame needs to mount the rear bellows frame and any structure for rear movements. My 8x20 Korona has rear tilt and swing. If you make the back too big for the frame, well there are cutting tools to solve that issue.

The bellow will need to be custom made anyways (a DIY project or writing a large cheque) and the bellows frames and bellows will need to be matched to the otherwise unrelated ends of the camera.

Sorry if all that is a blinding flash of the obvious, but it might be helpful...

[Michael Roberts]

John, I've been looking at the pic of your camera (http://www.largeformatphotography.info/forum/showthread.php?36782-Show-off-your-Large-Format-camera!&p=385655&viewfull=1#post385655)
and wondering--is it really necessary to start with two cameras or could you just replace all the horizontal pieces in the rear standard/frame? Doesn't seem to me that any extra hardware is needed....

[Michael Kadillak]

John, I've been looking at the pic of your camera (http://www.largeformatphotography.info/forum/showthread.php?36782-Show-off-your-Large-Format-camera!&p=385655&viewfull=1#post385655)
and wondering--is it really necessary to start with two cameras or could you just replace all the horizontal pieces in the rear standard/frame? Doesn't seem to me that any extra hardware is needed....

Michael has a point. Canham did just that with their wooden cameras that add a whole new dimension utilizing minimal components. The 8x10 wooden camera has a fitted groove that runs laterally along the bottom camera frame back and it has a tensioning bar that locks it in place. It serves as a rear shift as well as a way to release the bellows frame on the inside of the front standard and replacing the camera back / bellows by sliding it sideways off of the camera base. I went from 8x10 to 8x20 with the same base and front standard in a jiffy.

[John Jarosz]

I didn't say one has to use two cameras. I said that's what I did. It was serendipitous that I found the second basket case when I did.

For the rear of the camera I used none of the wood from either cameras, in fact the wood from the 2nd camera was unusable. What saved me a lot of work was using the brass brackets, shafting and gearing from both cameras. There is one bracket that positions the gears for focusing and forms the guide for the back to move in/out for focus. I used both sets so the knobs are placed outside the back (as in the original but further outboard) and the guides are in their original position along the rails. I have exactly the same rear movements as the original. The design of the 2D lends itself to doing this. There are other ways. Use whatever works for you. If you're really interested PM me and I'll send you some pictures that show this, but it's probably only applicable to 2D's. It's unimportant, really.

[Michael Roberts]

It's not unimportant to me, and probably others. Makes a big difference if you can take one beater and transform it to a larger size or if two are needed. Thanks for sharing...