Possible source for "MYSTERY" leaks and light breaches
Two FED cameras from two friends sent to me for examination were "leaking" light in the same way. Both made strange funnel-shaped/tapered fog marks which could be seen starting from the bottom of the film strip, and with variable densities, extending all the way into the frame. From the camera's perspective, this leak would come from some mysterious breach at the camera's upper portion.
The cameras were different- one was an early synched FED-2 and the other was a FED-3B. They were made years apart and came from different sources.
They showed the same leak patterns in the test negatives shot with them. These light leaks also looked similar to the fog marks often discussed and described in FSU "leak" threads. These would be fog patterns made by light breaching from some unindentifiable source in the camera. These are exposures which are suspected to have come from improperly installed light baffles, leaky shutter blinds, loose screws, or bad light gaskets in the seams.
Some are indeed fixed by repairing any of the parts given above. However, some leaks are so pesky that their real origin cannot be determined since the camera appears to be perfect when all the above mentioned parts are in order. This was how I found the two FED cameras.
Careful examination of the first FED (mod. 2) sent to me revealed that it had a tiny hole drilled on the top plate of the shutter crate/top plate assembly. It's a mysterious hole which does not seem to serve any real function. It's also not found in other FED-2. It's found right next to the sprocket shaft. Some previous repairist may have added it, or perhaps it's a tooling error made during its manufacture.
There's good reason to suspect that it's a manufacturing defect. The other FED (mod.3B) sent a few days later also had it, close to the sprocket shaft as well. And the test negative which the camera's owner sent with it was, luckily, uncut. Placing the full strip back into the camera rails revealed the location of the breach.
The last frame did not have any leak fogging mark- it did not reach the position where the breach was. The frame next to it showed that the fog mark at the edge of the film strip coincided with the mysterious hole.
The mystery holes in both cameras were very small. They were about 1mm in diametr. Light coming through the shutter collar or even the viewfinder windows could breach through them.
The holes in these cameras were plugged with balled-up (really tiny!) black rubber foam. The plug stopped the leaks in one of the cameras as evidenced by the 'clean' negative it shot. The second camera is yet to be tested for leaks, and I am confident that it too will shoot cleanly like the other one.
Last edited by ZorkiKat : 07-01-2007 at 10:05.