Jupiter 8 aperture ring misaligned?

[fymmot]

I just developed and scanned my first two rolls from my Zorki 4K + Jupiter 8 and I think some of the shots look strangely overexposed, with blown out hightlights. A few other shots are exposed perfectly. It's the stopped-down daylight shots (f/11 and f/16) that are the worst.

When I look at my Jupiter-8, it seems to me like its aperture ring is misaligned by 2-3 mm. I hope these images show what I mean:

I have two questions for you:

One, do you think it's probable that the lens is the cause of the overexposure problem? Unless I'm mistaken, a setting of f/16 on the lens would in reality be somewhere around f/10-11 if it's misaligned. I'm new to film cameras, rangefinders, lightmetering, developing, printing and scanning so I know there are many variables to consider but I'd love your input!

Two, is there a way to rescue badly overexposed films? Unfortunately I shot 6 rolls this weekend in Paris before noticing the problem and I'd hate for them to be ruined! I read something about "push and pull processing", is that what I want to do?

Thankful for your help!

 

[Sonnar Brian]

Someone probably unscrewed the optics module, perhaps even changed the shim.

The optics module simply unscrews, unless someone cemented it in or screwed it in and got a thin shim caught in the threads. I've seen both.

ANYWAY: use a rubber mousepad and try to screw the optics module in a bit. It should line up at the F-16 mark, as it is most critical. If the module cannot be screwed in, someone has changed the shim to align the lens. If this is the case, you need to undo the three set screws that old the lens in. Again- rotate the ring until F16 lines up. Tap out some holes for the new position, screw the set screws back in.

 

[fymmot]

Wow that was far easier than I thought! I just tightened it as much as I could and its now perfectly aligned! Thanks a lot!

 

[Sonnar Brian]

I love the "That was Easy" replies!

Sometimes when taking a filter off of a J-8 or J-3, the optics module unscrews before the filter comes off. Just screw the module back in, until it correctly lines up with the aperture index. The lens will also retain its collimation (focus agrees with the Rangefinder) when it is screwed back in to match the index.

 

[fymmot]

It sounds like that could have been the case. The optics module was a tiny bit loose.

Now for my (probably) already overexposed 6 rolls of film... Should I try cutting down the developing time to compensate for it?

 

[wolves3012]

I
One, do you think it's probable that the lens is the cause of the overexposure problem? Unless I'm mistaken, a setting of f/16 on the lens would in reality be somewhere around f/10-11 if it's misaligned. I'm new to film cameras, rangefinders, lightmetering, developing, printing and scanning so I know there are many variables to consider but I'd love your input!

One stop error isn't too serious on a print film, it would be for transparencies though. If it looks way over-exposed, it's more likely to be your metering techniques, sorry to say.

 

[fymmot]

After developing a few more rolls, I suspect I know what the problem was: a combination of the aforementioned lens issue and me overdeveloping the film. I think my D-76 was a few degrees over 20 C but I didn't adjust the times which led to dark negatives. At least that's my hypothesis.