IIIc -- light leak or what?

[payasam]

In the last roll I exposed in my IIIc, these frames came from the lab with a roughly 3 mm wide dark (not black) strip running along the full length, some distance from the top edge: 16, 17, 21, 24, 30 -- that is, the edge near the bottom plate. Three lenses were used: a 35 mm for frames 16 to 20 and 30 to 33; an 85 mm for 24 to 29; and a 50 mm for 21 to 23. Two of the five frames were verticals. Rolls exposed earlier showed no such problem. The lab insists, as well it might, that its machine is light tight and cannot be the culprit. Can anyone think of anything, perhaps a shutter malfunction, which might have been the cause? The bottom plate seems all right, but I have played a flash-light all around it on an otherwise blank frame just as a check. The only pattern I can see is that 16 (but not 17), 21, 24 and 30 were taken immediately after lens changes. I change lenses in the shade, of course, and the very edges of the frames in question were fine.

 

[laptoprob]

examples? How does it look?

Rob

 

[payasam]

On a print, a narrow band which is lighter than the rest of the picture. I'd have posted an example, but my scanner's cable seems to be annoyed about something. Have just taken two pictures after waving the lens-less body in front of a window, once with shutter cocked, once without. This way, I should know if a curtain is letting in light -- or if both are. I put on a lens before taking each picture, I might add: a Summaron 35/3.5 set to f/4 and infinity, subject around 7 or 8 feet away. This will also be a test of the legendary Leitz optics. Will I be able to tell that the frame contains three rows of books or will I see a herd of elephants?

 

[FPjohn]

Mid roll...

Mid roll...

Hello:

I get some mild light leak-one frame-when changing lenses mid roll in daylight with my IIIB. Normal? and not a big deal.

Your Summaron is likely to give sharp moderate contrast images-enjoyable!

yours
Frank

 

[FrankS]

On the negs, does the dark band continue between the frames or is it only evident within the frames?

 

[Ronald M]

Camera needs new light shields. It happened to both almost new M6`s and my M3.

The new ones are mylar and should last forever. Changeout was $75 at DAG. I don`t know if mylar replacements are available for screwmounts. maybe Don can trim M versions or they are direct replacements. In any case, write and ask if he can replace them. He answers mail daily.

If you can scan a neg or print with the problem send it on the e mail. Send the bad negs with the camera so you r problem is diagnosed properly.

 

[payasam]

Frank (FPjohn), I used an identical Summaron for 17 years. It was older and rather beaten up, but I loved what it did. For me, a frame thus damaged *is* unfortunately a big deal. Frank S, the dark band doesn't cross the space between frames, but an even narrower little bit of it, end not a right angle but wedge-shaped, goes outside the area of the frames affected: rather less than a millimetre, I'd say. As soon as I finish with this test roll, I'll take a good look at the gate and the baffling. The results also should tell me something. Seems to me you're on to a scent. Ronald, I do not understand what you mean by "light shield". Do you want me to send a scan to DAG or to RFF? I propose to send one here soon anyway. Plenty of fine diagnosticians in this clinic.

 

[payasam]

Right. Trying to put up a scan of two prints, same subject at different apertures. The frame on the left, which has the light band, was taken first, just after the lens was changed.

 

[FrankS]

If the light leak appears only within the frame of the image and not between frames or above or below frames, that would suggest a shutter problem.

If the light leak appears on the film inside and between, or above or below the image frame, that suggests a light leak from the back, top or bottom.

 

[laptoprob]

You stated a smaller part of the light band crosses the edge of the frame. That rules out a light leak from behind: at the rear side there is no frame boundary making a difference.
Yet from the front it is very possible to bet a bit of light going around the edge of the frame.
The light pattern only occurs after changing a lens? Or after having the aperture open without a cap for quite some time? Possible curtain problem. It could also be light is passing around the shutter. If there is too much space between the baffles and the curtain.
Shine a strong light through and look from behind. That should tell you a lot.

good luck, Rob.

 

[FrankS]

With bottom loaders, one unfortunately can't see behind.

 

[payasam]

Thanks, Frank and Rob. Band continues a little beyond only those frames in which it is present. No trouble outside frame area. No general fogging. So far as I can make out, this band thing has appeared only in the first frame exposed after a lens change. Lenses have remained mounted for long periods only with hoods, but no trouble there. I do not see how it could be a curtain problem. Each curtain moves, as a unit, across the entire width of the film, so there's no reason for just one narrow band to be affected. My thinking is along the lines of what you say last, Rob. When there's no lens mounted, light sneaks in under the shutter and is reflected on to the film. I shall also check the film gate for possible problems.

I shall stick in a white card, Frank, and look into the bottom.

 

[doubs43]

When you change lenses, have you already advanced the film or do you advance the film afterward? It seems unlikely to me that you'd have a problem that appears ONLY after changing lenses if you advance the film AFTER making the change. Changing the lens should only effect the film that's in the film plane aperture while the change takes place.

I hope that makes sense.

Walker

 

[laptoprob]

My IIf is only 2 screws away from looking at the back into the shutter. I was surprised about that. This means I can easily check focus and everything. My curtains are in great shape. No film through though, waiting for strap lugs and a new leather skin.
How difficult is the top to remove? Just all windows and knobs off and up?

cheers, Rob.

 

[FrankS]

I do not see how it could be a curtain problem. Each curtain moves, as a unit, across the entire width of the film, so there's no reason for just one narrow band to be affected.

What could be happening is that the 2 curtains (which form a slit that travels from top to bottom of the film gate), could be slowing down at that spot, forming that band of increased exposure. Just a guess, but I think it's time for a shutter CLA.

 

[payasam]

Makes limited sense, Walker, because either way I'd have a frame with a band. My negatives tell me that, for example, after a series taken with a 35 or a 50, the first frame taken with an 85 shows the problem. Rob, some months ago I downloaded illustrated instructions on how to disassemble a IIIf. Should be on my hard drive somewhere. Writing almost illegible, though. You serious about this? Frank, if you look at the pictures you'll see that the band runs along the entire long side of the negative, that is, from one end of the shutter's travel to the other. They are two vertical pictures ("portrait orientation") side by side, and only the one at the left was affected.

 

[FrankS]

payasam, I'm sorry! I've been thinking about my Kiev vertical shutter travel, not the Leica horizontal shutter travel! Please disregard what I said.

 

[payasam]

Frank, I guessed you'd mixed up shutters. Happens to the best of us. Happens to me too damn often, as a matter of fact.

 

[ZorkiKat]

Frank, I guessed you'd mixed up shutters. Happens to the best of us. Happens to me too damn often, as a matter of fact.

Payasam

What vintage is your IIIc? I have a war-production IIIc which produced fog marks like that after restoring/repairing it. I've checked the screws and places where the plates joined and everthing looked sealed and tight. There is just one light gasket found, its a black plush strip stuck to the body shell, under where the slow speed dial is found. Replaced this too, and the fogging continued. It took me long to find where this was coming from, until I noticed that the space below the rewind knob, and right above where the film cassette goes, seemed to be missing something. Light seems to be breaching the space between the knob and the plate. I put some baffles there, black felt and black paper mostly- and the fogging stopped.

Jay

 

[payasam]

Jan, mine's post-war: '46 or '47, going by the serial number. Single body casting, not built-up. Was your fogging in the same place as mine? Within the frame only, and a narrow strip along the direction of film travel? From what you say, it doesn't sound as if it had anything to do with changing lenses. Still, it's something I'll look into. Thanks.