Likely spots on Fed-3 for light leak?

[KenD]

I have a Fed-3 that has a light leak somewhere in the back. It produces a verticle (dark on negative) band roughly mid-frame on roughly half the shots (test roll in bright sunlight, no case) that extends into the sprocket margin. The contrast seems low with an I-61, may be some general fogging as well.

Any particularly likely spots for such a leak?

KenD

 

[kb244]

A band vertically eh? I am not sure that would be light leak, since leaks are usually fogged instead of bands.

Perhaps your shutter is getting slow, stuck, or speeding up in the middle affecting exposure in that general area as the band could be from the edge of the shutter curtain.

 

[KenD]

The "band' is not sharp edged, and it extends into the sprocket margin. If it were the shutter I'm assuming it would be just in the frame.

KenD

 

[kb244]

The "band' is not sharp edged, and it extends into the sprocket margin. If it were the shutter I'm assuming it would be just in the frame.

KenD

True, but shutter problems don't have to be sharp edged which is why I mentioned it. Perhaps a scan would be handy.

 

[ZorkiKat]

Try looking at the area where the sprocket shaft is. Close to the film gate. This would be the plate where all these are attached to. If you find a hole there which isn't filled with a screw, chances are this would be the source of your light leaks.

I found such holes in two cameras (a FED-2 and a FED-3) which their owners have sent to me to check. They had been getting vertical fog marks on their pictures too.

I had initially rounded up the usual suspects- pinholes on the shutter, improperly closing shutter blinds, or even the usual loose fastening screws on the body. They all seemed to be in order.

The origin of the breach would have remained unknown until one of the owners showed me his uncut negative strip. The last frame did not have any fog mark. Lining up the final frame against the film gate lined up the fog mark with the hole on the camera's ceiling. It was right next to the sprocket shaft.

Why there are holes like these- they serve no fastening or any other functional purpose- is a mystery. I would speculate that they were boring errors made during the camera's assembly. Drilling at the wrong part of the plate for instance, for screw holes and such.

If you do find any hole, just cover it with a bit of black paper. Or fill it in with black rubber foam- something from a discarded mouse pad will do.

Jay

 

[wolves3012]

Why there are holes like these- they serve no fastening or any other functional purpose- is a mystery. I would speculate that they were boring errors made during the camera's assembly. Drilling at the wrong part of the plate for instance, for screw holes and such.
Jay

Where exactly were the holes, in the stamped plates or cast parts? If they were in cast parts they may be related to the mold construction for structural reasons or metal-flow reasons.

Interesting piece of detective work anyway!

 

[ZorkiKat]

Where exactly were the holes, in the stamped plates or cast parts? If they were in cast parts they may be related to the mold construction for structural reasons or metal-flow reasons.

Interesting piece of detective work anyway!

The holes were in the cast parts. They don't look to be "casting" holes, rather they appear to have been drilled, basing on their quite roughly cut appearance. They were about 1mm in size.

Found them right next to the sprocket shaft on both cameras. The FED-2 and FED-3 which I found with these holes were made years apart. These don't appear in other samples where the cast plates were smooth. These didn't have any holes which appear to have been plugged.

Jay

 

[rick oleson]

My FED-3 leaked through the body from the front: I don't recall (maybe never figured out) just where it was entering from outside, but it came into the film chamber on the left at the seam where the inner chassis meets the front shell (the shell is attached with 2 screws from the front at this location). I just used black photo masking tape to cover this seam on the inside.

 

[KenD]

Thanks folks for some great info. I think I may have found the problem. There is a threaded screw hole in a slanted plate that seems to connect the inner chassis - shutter crate (?) to the front chassis. It is missing a screw... and, another fed-3 has a screw there. It looks as if the light leak would come from somewhere on the front chassis, where the screw ties in, since the slanted plate has cut out sections that would leak light anyway.

I know this is a little vague without a photo - but does anyone know what size that screw would be, and if it can be installed without dissassembling the works?

KenD

 

[wolves3012]

Thanks folks for some great info. I think I may have found the problem. There is a threaded screw hole in a slanted plate that seems to connect the inner chassis - shutter crate (?) to the front chassis. It is missing a screw... and, another fed-3 has a screw there. It looks as if the light leak would come from somewhere on the front chassis, where the screw ties in, since the slanted plate has cut out sections that would leak light anyway.

I know this is a little vague without a photo - but does anyone know what size that screw would be, and if it can be installed without dissassembling the works?

KenD

Firstly, are you talking about a FED 3A or 3B? Do you mean one of the four screws on the front of the camera, holding the crate and body together, the chrome, cheese-head screws? A picture would help, if possible...

 

[Mauro]

It is seems to be the same problem I had with my Fed 3B.
I discovered that the screws on the front chassis (on the same side of the sel-timer lever) were loose: as a risult, the line of contact between the shutter crate and chassis allowed light to mark the film with a vertical band.
In short, the light entering from the lens found a way to reach the film near the winding roller. I tightened the screws and I placed a strip of black tape over the line of contact (inside the camera).
Hope this helps