Eddie just pointed me to this thread. For the 11x14 I made, I used foam core to make a pyramid structure which I painted the inside black. The back was simply a paper box glued and gaffers taped into place, and the lens was simply gaffers taped onto the small part of the pyramid. I suppose that if you wanted to make multiples and use the same lens you could make a little plate hinged on the side, then put everything into a darkroom/giant changing back, take the lens off and close the hing, then tape it all up so it's light tight. Or just have multiple giant changing bags I guess. The foam core is surprisingly rigid and sturdy once all taped and painted. For the tripod mount I simply glued/taped the quick release to the bottom of the camera (which is very lightweight) and mounted it on the tripod.
And here's the part you are probably wondering about; to determine the focus I simply put the lens on my view camera and measured the bellows draw required for the focus distance I liked. I looked into doing the math, but I wanted to experiment with focus distances and find one I liked. For example, my camera was designed for portraits, so I made the focus so that it was a head and shoulders shot on 11x14, which was a certain distance from the lens. I had the lens on the 8x10 so I just "guestimated" how much bigger the 11x14 frame would be and adjusted as necessary. Thus, I knew that if I wanted that head and shoulders shot I would have to move the lens that distance from the subject to "be in focus." So I simply shifted the tripod/camera until it was that distance from my subject when taking the picture. I used the lens cap for a shutter. For framing I suppose it would have been easy to make a wire frame viewer of sorts, but I just guessed and actually got it in two tries (I was using paper negatives). Since I could take the tripod plate off, I could keep the framing from the previous shot and adjust as necessary after seeing the negative.
If you don't have another camera with bellows long enough to test the lens on you could even just get a sliding poster tube and tape the lens to the front and some vellum on the back, then measure the bellows draw and distance from the lens to the subject. This method would make it quite a bit harder to guess where the bigger frame ended though.
I would be happy to help you more with the project and/or send you some photos of mine, but I am leaving for a trip to China for the next three weeks. I will be back September 20th if you'd like to get in touch then. Good luck! These things are fun!
I've built a 5"x7" sliding box camera from black foamcore, which uses a foamcore sandwich film holder; since I only made 1 holder, it's essentially a 1-shot camera. But I can use a regular sized changing bag in the field, since the entire camera doesn't have to go inside the bag, only the holder.
The film holder is a sandwich of 4 layers of 1/4" foamcore, with a foamcore darkslide that is designed to stay in the side slot of the holder; you pull it out to a preset stop point, and the darkslide maintains a light-tight seal against the body of the camera. It also has a removable view screen, built to the same size and thickness as the film holder, but which uses a thin sheet of clear plastic, which has been sanded down on one side; it works remarkably well for previewing the scene.
There is a remarkably good resource for camera-building ideas, the George Eastman online collection, at this link.
Here's an example of a sliding box plate camera from their collection, who's general concept I used as inspiration for my foamcore camera. I used an old sheet of plywood for the bottom plate, to which the front half of the camera body is permanently affixed. The front half needs to be the larger of the two halves of the nesting boxes. The back half nests inside the front half, such that any light leaking through the seal won't shine directly onto the film. You'll notice that the back half of the box rests on the bottom platform as it slides, such that it will stay sufficiently aligned with the front box to prevent light leaks. This is an especially important feature to incorporate in your camera if you expect to be extending the boxes out near the limit of their nesting, where there is minimal contact between the side walls; you want the bottom platform to support the rear half, preventing it from further movement.
If you line the inside of the box with black adhesive craft felt (from stores like Hobby Lobby or Michael's) it'll totally dampen any light reflections. The black felt is also a good material to use on the side walls of the box halves, where they slide together, providing for a light-tight but dynamic seal.
PS: My avatar was a self-portrait onto Efke's direct positive paper using this camera. I was using a 150mm binocular lens as the taking lens, nearly wide open around F/4.5, with a simple lens cap shutter.
Nice link Joe, ...thanks for posting.
If you have a box that big, why not put a white image plane hinged at the bottom in the back. You can view and focus through a hole in the top of the camera, then reach in and fold the image plane down onto the bottom of the camera. The plate would then slide in where the image was. Saves the weight of a ground glass and allows focusing.
To bad you live so far away, I have an 18"x24" process camera you could have for parts. Good ground glass, bellows are intact, and vacuum back to hold film flat.
Originally Posted by Robland
A quick and dirty way to make foam core more rigid is to coat it with fiberglass - Home depot or any autoshop should sell glass mat and resin - or you can find it online. Make sure to get epoxy resin, as the polyurethane stuff eats away foam core - it would be good to reinforce corners and load bearing places.
I though of doing this as well, but I was considering making big box with a smaller sliding box in front that held the lens, that way I had some limited focusing distance. So with a 24" lens, I was going to make a big 24" cube that had a smaller 18" or so cube in the center the opposite face of the film plane that slid out to 36". I wouldn't rely on my calculations, but when I tried to figure it out, with a 24" lens this gave me focus from 5 feet to infinity.
I have abandoned the idea for now, since I decided I really wanted movements and 1:1 magnification, so I'm trying to figure out bellows.
"I have abandoned the idea for now, since I decided I really wanted movements and 1:1 magnification, so I'm trying to figure out bellows."
19" Artars, APO Raptars, Process Ektars, ect. are rated for 16"x20" at 1:1 so you really don't need a 24" lens, very likely get by with a 16" lens. Portrait lenses in the 20" - 24" range are all far too heavy for a foam-core camera. For bellows and movements just canibalize a 5x7 field camera and adapt to the front of yours.