The idea of this camera started with vintage Profile Spotlight, that I wanted to restore, but found out, that some of internal lens elements were shattered. The only lens element, that was undamaged was the front element of it. Upon some closer inspection I discovered, that this element can project image circle big enough, to cover 8X10 area.

The obvious use of it was to create large format camera. but I didn’t want to bother with large format film and other hassles of creating proper large format camera, just for this weekend experiment. So, I decided to create something like Camera Obscura and  photograph projected image with DSLR.
Below, you can see basic idea of the camera. As you see – the design is similar to any other large format camera, except this has DSLR added to it, to photograph projection on ground glass

 

Fast forward two weekends and here is the finished camera:
“Let me show you its features!”

Because I didn’t want to invest much(anything) it this project – the camera was created from scraps and other trash lying around garage.

Lens was mounted in a piece of plywood, so I can flip it around, because the lens somewhat changes its look depending on which direction it is flipped. After some testing I found out, that focal length and f/stop of this lens is roughly 380mm f/5.1, that in 35mm equivalent would be something like 55mm f/0.73.

Bellows were created from office paper and black trash bags. Folding bellows was hardest part of this project. For more information, I suggest to visit jbhphoto.com, where you will find .pdf file with the most comprehensive information about making bellows on the interwebs.

Ground glass was made from 2.5mm plexiglass, that I wet sanded with 800 grit sandpaper. At first I tried 1500 grit sandpaper, but I found out, that it was too fine and didn’t scatter light enough, to project clear image
Also, the lens I chose for this project was Tamron 17-50mm f/2.8 VC that was used at its widest position. This allowed me to fill the frame with ground glass roughly 310mm. from camera’s image plane.

For focusing I made rod exertion, so I can focus the lens from back of the camera, while looking at live view.

To make this contraption usable on location – I tried to make it foldable and somewhat convenient to travel with. Well … as convenient as almost a meter long camera can be. 🙂

 

Now, let’s get to the important part of this project – the photos!

The operation of this contraption is straightforward. At first I focused DSLR on ground glass and locked the focus. Then I used Live View to frame and focus the large camera.

Because my tripod head was barely stable enough to hold this contraption – I had to use self timer to avoid camera shake. Also, shooting in the wind with this thing was major pain in the rear.

Editing raw files was rather straightforward. After removing rather heavy vignetting – photo was edited like any other photograph.

 

Conclusions.

This was very spontaneous project, so I didn’t do much planning. At first I thought, that this will be “make it and throw it out” kind of project, but after playing around with this camera I think, that this should be a “thing”. I know that there are quite a few photographers with field cameras laying around, who would like to take them out for a spin once in a while, but don’t what to bother with process and cost of large format film. This should remove some of these problems. Sure, this won’t satisfy everyone, but this is better than collecting dust.

Here are some tips for someone, who want to try something similar:
Tripod: You should use sturdy tripod, with big quick release plate, for camera this big. Also, ball heads are not very convenient for operating camera this size.
Ground glass: I suggest to make proper ground glass, by grounding glass with Silicon Carbide powder, or chemical etching. This should avoid most of sanding scratches. And a Fresnel lens in front of focusing screen should remove vignetting.

 

That is pretty much it!
If you want to see my other DIY projects – feel free to snoop around this blog.
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