Once your camera is completed, it's time to test it out. Load your film holder with black and white film. I used TMAX 100 and all my comments are based on my experience with that film. Make sure you load the film into the holder emulsion side up. When you place the notches in the film on the right hand side of the top edge, the emulsion is up.
Once you have loaded the film holder and placed it in your camera, with the back holding it in place, put the camera on a tripod or stable surface and level it. Point it in the direction you want. I then place a small sandbag on top of the camera to try and minimize any camera movement when I pull and push the shutter. Once the camera is all set up and stable, pull the dark slide out of your film holder with a smooth motion. Then open your shutter for 3 or 4 seconds if in bright sun.
The exposure time of 3 or 4 seconds assumes a pinhole camera of f272 and ISO 100 film. Using the sunny 16 rule, f272 in bright sun should be exposed for about 3 seconds. For different apertures, you must calculate new exposure times. Remember that for each time the aperture increases by 1.41 (square root of 2), the amount of light that reaches the film decreases by 2.
Here is an exposure guide for ISO 100 film in bright sun:
Aperture | Shutter speed ---------+-------------- f16 | 1/100 f22 | 1/50 f32 | 1/25 f45 | 1/10 f64 | 1/5 f90 | 1/3 f128 | 1/2 f181 | 1 sec. f256 | 2.5 sec. f362 | 5 sec. f512 | 10 sec.
Keep in mind that with very long exposure times you need to compensate for the reciprocity characteristics of the film by increasing the exposure. Kodak recommends a +1/3 stop increase in exposure when a one second exposure is computed for TMAX film and they recommend a 15 second exposure when a 10 second exposure is computed. So at f512 you really would need to use a 15 second exposure instead of 10 seconds. Also, remember that the reciprocity of most of Kodak's other films are much worse than that of TMAX.
Try to slide the shutter as smoothly as possible. A little wax on the edges of the shutter seems to help. The main considerations in using the pinhole camera are preventing light leaks and keeping the camera stable. Be sure that the film holder is well seated before pulling the dark slide. Only keep the dark slide out for as long as necessary. Tradition holds that the white side of the dark slide is out for unexposed film and the black side is out for exposed film or when the film holder is empty.
At least initially, take careful notes of everything you do in using your camera. It's hard to learn from your mistakes if you don't remember what you did.
Pinhole photography Building a pinhole camera Building a stereo pinhole camera Pinhole photography gallery Stereo photography Stereo photography gallery Back to home page