Strange spots

[marke]

Last month I picked up a Canon IIIA that looked to be in great shape. Unfortunately, the Serenar 50/1.8 isn't in as good of shape as the camera, with all it's many cleaning marks and tons of haze.

Anyway, I wanted to see if the camera had any other issues, as the shutter curtain seemed to have some visible marks that might cause light leaks. I screwed on my Industar-22 50/f3.5. I loaded the Canon with a roll of Kodak BW400CN, and was surprized with the results. I'm guessing that this has nothing to do with the shutter curtains, but more to do with something on the lens. It has it's share of cleaning marks, but the spots I see here don't seem to be obvious when viewing the lens with a light behind it. These spots show up exactly the say way, same pattern and positioning in each frame. Any body know what they are?

 

[marke]

Upon viewing another image from this roll, I'm beginning to think that this might be a shutter curtain problem after all. The image in the first post was at 1/100 sec. This next image is at 1/60 sec. The spots are definately brighter in the longer exposure.

 

[maddoc]

The spots seem to be in identical position in the two frames but with different intensities. Looks like holes in the shutter to me. Test it without the lens, shutter cocked and shutter released and hold the camera against the bright sun. The film frame should be blank.

 

[bennyng]

I don't think you can look through the curtain of the IIIa as it's a bottom loader. Maddoc's suggestion of trial exposure on film might be more feasible.

Cheers,

 

[Doug]

Pinholes in the shutter, certainly. I had personal experience with that problem on a Nikon S2 years ago, same effect as you illustrate.

 

[Mattikk]

Keep shooting. The spots look wonderful! I'm not kidding.

Would definitely be interested if a saw shots like this in a gallery. I might even buy them.

 

[marke]

I think I'll try maddoc's suggestions, as the camera is a bottom loader. I'm also guessing that it's pinholes, but I just wanted to confirm it with someone else, since I've never actually seen what they look like before now. I just reloaded a partially exposed roll into this camera, and I'll fire off a few more shots.

I think I only paid $30 or $40 for both the camera and lens. I knew the lens was probably shot before I bought it, but I was hoping the camera was still usable. Except for the shutter curtain, the camera looks almost brand new. Anyone ever replace these before? I don't know if anything is available for a Canon RF, but it might just be a fun learning project if I can get the parts.

Thanks for your replies, everyone.

 

[John Shriver]

It's pretty much the same as on a Leica IIIa. Only thing is that you probably need thin shutter curtain cloth. The Micro-Tools and Aki-Asahi cloth is too thick. John Goodman (interslice) may have some thin shutter curtain cloth.

The only hassle is that the position of the curtains is really critical on the Canon cameras with 1/1000 shutter speed. There's no adjustable cams to trim the top two speeds, as there is on the Leica IIIc. So you will have to get the curtain exactly correctly located on the drums. I'd say tape the closing curtain to the drum until you find the correct location, and then glue it with shellac.

Early Canons, and most Leica screwmouts, used shellac to glue the curtains down. Later Canons used something like Pliobond, which is much more difficult to deal with.

I red-did the curtains on my IV-SB2 once with the Aki-Asahi curtain, I need to do them again with the thinner curtains, use the tape technique, and switch to shellac. (The camera originally used the Pliobond-type glue, which was hassle to clean off with MEK.)

 

[marke]

Thanks, John. That info about getting thin enough curtain cloth and the positioning info is invaluable. Man, this place has a wealth of knowledge behind it's keyboards!