Mamiya 645 Pro possible light leak?

[xexets]

Hello everybody! I wonder if you could help me assess a problem I might have with my new Mamiya 645 Pro, which I got from ebay a month ago.
So far I have developed 7 rolls. 2 of these show a light leak kind of problem. These two rolls have been shot on two different backs. No other roll (which was in those same backs, and was shot under comparable conditions) shows the leak.
Basically, as you can see from the pictures below, some consecutive pictures (and not all in the roll) show an overexposed line or two in the left area (thus the leak should be somewhere on the right I guess).
Since this happened on two different backs I guess if it is a light leak it should be on the body? Or do you think it could be some kind of shutter/curtain problem? Or maybe I just did not load the film correctly of change the backs carefully or stored those two films in a good way? I am puzzled because of 7 rolls only 2 show leaks.

1st set with possible leak: flickr.com/gp/xexe/s4AGDk/

2nd set with possible leak: flickr.com/gp/xexe/812D9M/

As you can see only some of the photo show the leak.

Could you please help me with this?
Many thanks!

 

[compur]

Yes, it could be a light leak. Tape up your camera and see if it goes away and/or look for the leak (usually deteriorated foam light seal material -- replace it).

 

[xexets]

Thanks. It looks indeed like a light leak, but why only on 2 out of 7 rolls? That I can't understand. All rolls were shot in comparable conditions and the backs were removed and replaced with all rolls loaded, so I can't see how it could have happened! Where should I tape the camera, on the connection between the back and the body?

 

[compur]

Light leak effects don't usually happen instantly. They are more commonly cumulative effects of a very dim light that reaches the film so they usually have more to do with how much time has passed since the last frame was shot. That is, if you shoot up your roll quickly there is less chance of a leak being visible then if you pause your shooting for longer periods between frames.

Yes, tape your camera between back & body. Or just look for deteriorated foam seals and replace them. Most Japanese cameras made from the 1970s-90s have this problem with seals because the manufacturers used a foam material that degrades over time.

 

[xexets]

Thanks, I will indeed tape it and try it out. I have checked the whole body and back and there are no seals at all. It looks as if the the Pro version is built without seals but only tightly fitting plastic grooves. As a matter of fact, there is no seal replacement kit for the Pro (to the best of my knowledge!) I'll try out the taping. Thanks!

 

[limr]

Is that Piran in the second set?

 

[compur]

Thanks, I will indeed tape it and try it out. I have checked the whole body and back and there are no seals at all. It looks as if the the Pro version is built without seals but only tightly fitting plastic grooves. As a matter of fact, there is no seal replacement kit for the Pro (to the best of my knowledge!) I'll try out the taping. Thanks!

If the tape doesn't solve it and there are no seals to replace (assuming there never were seals) then you'll need to look elsewhere. It's always best to try the easiest things first.

 

[cgw]

There are no foam seals anywhere in the Mamiya 645 Super/Pro/ProTL backs or mounting surfaces on the bodies. I'd say the shutter isn't the culprit since the film(when the camera's in landscape position)runs vertically and the shutter horizontally. Is there any play between the back and the body at the top or bottom of the back? Sometimes the claws in the back shell don't catch the hooks on the body tightly enough. Wear on the claws in the back shell might be preventing a light-tight connection. There's a very small amount of play with several backs of various ages I use on a 645 Super but never any light leaks.