complete failure of an Angulon 90mm 6.8 rear group

[koh303]

Never seen anything like this...
117496117497117498

I guess they do have a limit to what they can take...

[Steven Tribe]

I think others have! At least, I think I can see separation!

i read your serial number as around 2,500,000 - which makes it around 1950. This is the period with the development of synthetic glues. These are known for complete adhesion failures.

You can reglue with traditional Canada Balsam (easiest for the amateur).

[Misko]

i have same lens from 28xxxxx serial number batch & I have balsam failing on the front group :)
On the other hand I have managed to purchase Super Angulon 5.6 / 90 recently so I will be giving up on fixing this lens.
if you wish I can send you rear element (and even front one if you wish) for the price of shipping. Only issue is that I am currently living in China so I am not sure if it is worth for you - since I would ask you to cover the cost of the shipping. Let me know if you're interested.
Cheers,
Milos

[domaz]

If you look closely at pictures in Ebay auctions it seems a good portion have seperation of some sort. So it's not totally surprising.

[Kzphoto]

I spoke with John van Stelten of Focal Point about an old Grandagon 58/5.6 which I wanted to repair. The rear group had a massive amount of separation and I thought it best to fix the lens.

John told me that many older lenses used exotic glasses with different expansion rates, causing separation on cemented groups. Makes sense, I suppose.

[koh303]

It does... but what does not make sense, is that this lens does not do anything special in any way, and it seems like so many other lenses were just not so well made. And its not that i expect things to last forever.... I have lenses from the 60's and 50's which are top perfromers and i do no expect them to fail any time soon, and i am sure there are many here who use lenses twice or three times as old and have the same sentiment.

[hoffner]

It does... but what does not make sense, is that this lens does not do anything special in any way, and it seems like so many other lenses were just not so well made.


Before you start to make broad judgements about lenses "not well made" - do you know the history of this specific lens, how it was treated, how it was cared about in its life?