What's this?! Black fungus?
- Thread starter bernardblack
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Sejanus.Aelianus
Veteran
From the picture, it looks mechanical, to me. Some components of the mount, perhaps?
Dan Daniel
Well-known
When was the lens made? I've seen something similar (well, I'm guessing from a schematic photograph) in a late '40s/early 50s Tessar on a Rolleiflex. It was almost like a black 'tar' that had melted or dripped out of the mount? Someone mentioned that Zeiss had some supply problems after the war and seemed to be using some strange lens mounting compounds around this time. I've also seen something of a different flow pattern but possibly the same issue on another Tessar.
In one case for me, the 'tar' came off of the glass but had affected the coatings slightly. Lens took fine photos. In the other case the 'tar' had stuck to the rim of the shutter blade opening and needed to be chipped away from the metal. Once all the chips and dust were cleaned out things were fine.
Well, just a thought.
In one case for me, the 'tar' came off of the glass but had affected the coatings slightly. Lens took fine photos. In the other case the 'tar' had stuck to the rim of the shutter blade opening and needed to be chipped away from the metal. Once all the chips and dust were cleaned out things were fine.
Well, just a thought.
bernardblack
Member
I should had added more pictures. It is contax mount
I don't think it is mechanical.
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Sejanus.Aelianus
Veteran
Those later pictures do look more organic. I think Dan's suggestion sounds feasible.
bernardblack
Member
That makes sense. This is a post war lens and made in the late 50's when zeiss-opton was using a different type of lens glue. Most of the late 50's zeiss-opton suffer from lens separations due to the glue. I just wanted to make sure if properly restored and cleaned I would still achieve great pictures. Also know if it will affect the coating.
Dan Daniel
Well-known
In the second set, the left photo, is there separation along the left edge? A yellowish sheen, maybe 120 degrees, coming inwards up to 1/6 or so of the lens diameter?
My initial response was to the black blobs along the outer edge, upper right, in the first photo.
My initial response was to the black blobs along the outer edge, upper right, in the first photo.
bernardblack
Member
Yup, lens separation.
farlymac
PF McFarland
From what I understand about lens element construction, that looks like the Canadian Balsam having discolored. Most likely due to heat. I've got a Zeiss 440 finder with the same problem. Would take a complete tear-down, separation of the elements, and re-gluing to fix it. Not easy or cheap.
PF
PF
R
rick oleson
Guest
Separation was a common problem in Zeiss lenses of that time period - I gather that they were using a new synthetic cement that was supposed to be better than Canada balsam but turned out to age ungracefully. Usually the appearance of separation is a bright reflective area near the edge of the elements, spreading inward... the shape of your marks looks about right but I've never seen it look black. It might be that something has wicked into the crevice between elements after the cement separated. I don't know how you'd get it out. The synthetic cement is not as easy to unstick as Canada balsam, which itself is not for the careless or faint of heart.
