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Fotometric
Tinkerer
Username: Fotometric
Post Number: 2
Registered: 08-2012
Rating: N/A
Votes: 0 (Vote!) | | Posted on Monday, August 27, 2012 - 01:46 pm: | 
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Hi
A second optics question I need help on;
My latest aqcuisition (this is getting to be a habit) is a Rolleiflex Automat with 3.5 Zeiss Opton Tessar 75mm lens. When searching for information on this I came across a post on another forum saying this lens is badly put together. I'm taking this with a pinch of salt as others say it gives superb results.
I think mine needs aligning with the viewing lens or hood but bits of my test roll look great.
Anyway I took the front element off to clean some fungus; the second element seems to be held in place by green gunge, some of which has collected between the front elements and is visible with the aperture wide open, some of it has collected under the lens and I'm very surprised it hasn't stuck the shutter blades.
If I put the front elements face down on the table I can see that the second one with the gunge is stuck in at a slanted angle. Does this matter? What would the effect be?
Most of the fungus is further back but I can't get the rear element off yet. Do I need to proceed with caution with this lens? I'd prefer a camera with a small amount of fungus than a camera that won't focus!
Thanks! |
Cooltouch
Tinkerer
Username: Cooltouch
Post Number: 210
Registered: 01-2009
Rating: N/A
Votes: 0 (Vote!) | | Posted on Monday, August 27, 2012 - 08:39 pm: |
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I had a similar fungus problem with a Yashica Mat 124. It had some light fungus inside the rear element, and I ended up taking the lens standard off the camera because I didn't have a tool that would reach far enough inside.
The green grunge is probably corrosion from something made from brass. You can probably scrape it off lightly without causing a problem. Got a dental pick? Might try one of those for tight areas and/or crevices.
I've owned a few Automats over the years, both with the Tessar and the Schneider Xenar. While the last Automat I've owned had the Tessar and took great pics, I felt the Xenar was just a bit better. It seemed to have more contrast than the Zeiss. Still, it's real hard to go wrong with either one, as long as it's properly collimated and all. |
Rick_oleson
Tinkerer
Username: Rick_oleson
Post Number: 1227
Registered: 07-2006
Rating: N/A
Votes: 0 (Vote!) | | Posted on Tuesday, August 28, 2012 - 04:31 am: |
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I've had excellent results with Zeiss-Opton lenses. The glass should not be in at an angle, though - each element should be seated perfectly level in its mount. I can't imagine that any error large enough for you to detect could have gotten out of the Zeiss factory, so if it isn't seated correctly my guess is that someone must have had it apart before.
Cleaning up the rear element may be more of a trick than just getting it off of the shutter. The rear cell is 2 elements cemented together... anything that you can't clean either on the exposed rear surface or from the front through the shutter will be trapped in the cement layer between the 2 elements. Separating and recementing a cemented pair is an operation that's more likely to leave you worse off than better in the end, and I don't advise trying. So, don't worry about removing that cell - clean the surfaces that you can reach, clean the shutter and put it back together. |
Fotometric
Tinkerer
Username: Fotometric
Post Number: 3
Registered: 08-2012
Rating: N/A
Votes: 0 (Vote!) | | Posted on Tuesday, August 28, 2012 - 12:05 pm: |
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I've cleaned the green gunge from around the shutter fine, to me it looks like some form of adhesive though. Possibly the original lens cement that has broken down over the years?
Thanks for the advice Rick, I will leave the rear element alone. It's actually not as bad as I thought now I've had a second look; the fungus is gone and there are just a couple of specks of something in there that I can live with. They might actually be bubbles in the glass.
These two posts I came across have also helped make sense of things. A second look at one of the photos from my test roll had made me think 'Is that tilt/shift!?', and this seems to be confirmed by the more extreme example in the first thread below.
http://photo.net/classic-cameras-forum/00Xoct
http://photo.net/medium-format-photography-forum/00QO3p
The second element from the front was at a definite angle. It might have been apart before but it looks to me like the lens adhesive has broken down over the past 60 years and flowed downwards, oozing into the gap between the front elements and pooling around the bottom of the shutter, letting the element slip with it. With finger pressure I've been able to level it out a bit but I'm not sure how accurately and this has dislodged some crud between the elements.
I want to take the element out, clean out the gunge and reset it, but I'm not sure how to proceed here. I can't see how it's seated, will just dropping it back in put it in the right place? What do you glue it with, because right now I'm thinking super-glue (somebody stop me!)? |
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