Streaks on Film from a IIIc

[steve_taylor3]

I have got a IIIc and I think the camera is putting underexposed

streaks on the film parallel to the long edge of the frame, i.e. in

the direction of the shutter curtain travel. I have read in this

forum about this and that it is likely due to a rough edge on the

shutter curtains. On short exposures the rough edge causes

underexposure of the bits where the 'bumps' on the curtain edge are,

thus causing streaking in the direction of the shutter curtain

travel. This effect is more pronounced on higher shutter speeds, as

the gap between the curtains is progressively narrower and the bumps

on the shutter curtain take up more percentage of the gap making the

exposure. It is also more pronounced at smaller apertures, as if the

imperfections on the shutter curtains were being brought more into

focus. This all agrees with what I have found, as I have done tests

(pictures of a cloudless blue sky) at 200, 500 and 1000 speeds and

the problem gets progressively worse. I also varied the aperture at

each speed and it gets worse the smaller the aperture. I do know the

shutter curtains were replaced very recently (before I had it), and

indeed they look new.

 

I have looked inside my camera and found that the material of the

shutter curtains appear to be folded over a piece of metal and sewn,

thus making the edge of the curtain. Is this the standard means of

sutter curtain construction for screw Leicas? Since the material is

folded over the metal, the actual edge is formed by the material and

is a bit rough. There are also tiny bits of the fibre of the material

coming off this edge (they are like tiny bits of fluff standing

straight up from the edge of the curtain). I have an M6 as well and

the shutter curtains there have metal edges, which makes much more

sense to me, and I don't get the problem with the M6.

 

Has anybody else observed this with a screw camera, or better still

any idea of how to cure it? I have thought of painting the edges of

the curtain in the hope that the paint will glue the fibres down.

 

Or perhaps I am expecting too much of a 50 year old camera? Apart

from this the camera is great and very nice to use. I really am only

frightened of 500 and 1000, and I could live without them, but it

would be nice to get this fixed.

 

Thanks in advance for any reply.

[Troll]

Send it to DAG or Sherry, and get it fixed.

[paul hart]

Steve:

 

Could you post one of your photos of a cloudless blue sky for the benefit of the British contributors to this forum?

[steve_taylor3]

Would you believe I actually live in Blighty and took it in Southampton yesterday!

[pcg]

Steve,

 

You've gone to a huge effort to ask a question that can't be answered properly w/o expertise, & the ability to physically handle the camera. Just send the III off to DAG & have it CLA'd. I use two IIICs regularly & have them cleaned every 4-5 years w/o fail.

[roger c]

Or try Peter Grisaffi at Camera Repairs and Restoration, Luton. Highly recommended.