Testing for Light Leaks on the Sputnik stereo camera
One method that people have used successfully is to wire together a small battery and bright bulb. This is placed in the film chamber, and the whole think taken into a completely dark room. Once your eyes have adjusted, you can often see the light leaks visually.A second method is to do a film light leak test. This is done using a medium or high speed film. If you do your own film developing, this is easily done using a B/W film such as Tri-X. I have modified the original procedure I was taught as follows:
- Load the film in the camera in as subdued light as you can. Advance the camera to frame #2.
- Bring the camera outdoors and "bathe" it in sunlight for 10 minutes or so, turning frequently to expose all surfaces to light. If the sun is strong, be careful - the camera's black body can heat up rapidly! In this case several short exposures to sun with "cooling off" time are in order.
- Take an exposure. It is useful if this is underexposed by a stop or two, so that light leaks on the back plane can be more easily seen. Do Not Advance The Film!
- Bring the camera back into subdued light.
- Tape over all the "seams" where the camera back pieces meet the camera body, and tape down over the silver latch which holds the two back pieces together, with black tape (such as electrician's tape or black gaffer's tape).
- Advance to frame #10.
- Repeat steps 2 and 3.
- Unload the camera in subdued light, and develop the film.
When done, this gives you a good "before" and "after" idea of what the light leaks are on your camera, and how addressing the light trap can improve them.
Here are some scans from a test I performed on one Sputnik:
Note: Scans not yet installed....
Unmodified Sputnik Light Leaks
Sputnik Light Leaks with seams taped
So you can see that in this camera, simply cleaning up the light leaks makes an enormous difference. That's why it is the recommended place to begin!
