Contax III sonnar lens problem- fungus?

[Highway 61]

Also, FWIW, @ least in my experience, a lens w/a modest amount of separation, e.g., along the outer edges, can still perform decently.

I agree - many classic Canada balsam cemented lenses (including Leitz ones) have a tiny amount of separation starting, at the edge, in general in the rear element, and this is with no visible results on the pics.

Problem with those pesky epoxy cemented Carl Zeiss Sonnars is that separation affects the front element and quickly spreads out - Raid's saying that his lens has its "rainbow" over 75% of the front element surface. I'd call it hard separation.

The lens may still be usable anyway, the main result will be a heavy contrast loss.

A kind of Summar-Thambar Sonnar...

Yes Focal Point may very well fix it but their charges will probably be twice what another Opton 50/1.5 Sonnar in perfect shape could be grabbed for on the virtual global market.

Not worth it IMO.

 

[raid]

I agree - many classic Canada balsam cemented lenses (including Leitz ones) have a tiny amount of separation starting, at the edge, in general in the rear element, and this is with no visible results on the pics.

Problem with those pesky epoxy cemented Carl Zeiss Sonnars is that separation affects the front element and quickly spreads out - Raid's saying that his lens has its "rainbow" over 75% of the front element surface. I'd call it hard separation.

The lens may still be usable anyway, the main result will be a heavy contrast loss.

A kind of Summar-Thambar Sonnar...

Yes Focal Point may very well fix it but their charges will probably be twice what another Opton 50/1.5 Sonnar in perfect shape could be grabbed for on the virtual global market.

Not worth it IMO.

Thanks for the info on my lens situation. I have already a Summarit as my Thambar lens, so there is no need for another lens for dreamy images. Maybe I can find a replacement glass element for the lens. Focal Point may charge $250 to fix it.

 

[Highway 61]

Thanks for the info on my lens situation. I have already a Summarit as my Thambar lens, so there is no need for another lens for dreamy images. Maybe I can find a replacement glass element for the lens. Focal Point may charge $250 to fix it.

The separation isn't in the front element which is a single lens group.

It's in the second group which is a cemented triplet.

Anyway one should never swap elements from one lens to another - all the elements/groups are biased altogether in a single lens which is a unit.

$250 is what two mint Optons 50/1.5 should cost you.

Below is the Zeiss Sonnar 50/1.5 diagram. I have marked in red the probably defective elements cementing areas.

 

[raid]

The separation isn't in the front element which is a single lens group.

It's in the second group which is a cemented triplet.

Anyway one should never swap elements from one lens to another - all the elements/groups are biased altogether in a single lens which is a unit.

$250 is what two mint Optons 50/1.5 should cost you.

Below is the Zeiss Sonnar 50/1.5 diagram. I have marked in red the probably defective elements cementing areas.

I know the cost of a mint Opton, but I mentioned the estimated cost.I already own a clean Opton from Brian Sweeney.

 

[Highway 61]

I know the cost of a mint Opton, but I mentioned the estimated cost.I already own a clean Opton from Brian Sweeney.

This is something I can't get - feeling the need of buying an ugly separated copy of a clean lens which you already own.

That GAS just mystifies me. 😀

 

[raid]

This is something I can't get - feeling the need of buying an ugly separated copy of a clean lens which you already own.

That GAS just mystifies me. 😀

I wanted Brian to modify it into LTM, but I received an Opton even though the add just said Carl Zeiss Jena Sonnar. The Opton cannot be adapted to LTM by Brian.