Summar Fungus

[akptc]

This Summar recently fell into my hands. The surface of the front and rear glass look great but looking inside I think I see fungus damage. Wondering if this is indeed fungus and whether it may be possible to clean.

 

[Fuchs]

It doesn't look like the typical fungi. It looks like some sort of cement degradation/separation between the elements. The Summar has 6 elements in 4 groups, ie the second and third elements and the fourth and fifth are cemented duplets, and one of those groups looks like is suffering a bad case of separation.

 

[Luddite Frank]

I agree - fungus usually manifests itself as irregular strands or snowflake-like clumps...

This looks like balsam separation.

If the glass is not scratched, it might be worth sending to someone like Ken Ruth for re-cementing ?

It would be interesting to shoot with it first, though... just to see what happens. 🙂

 

[akptc]

Thanks a bunch for your advice. I am definitely going to try the lens out before sending it in for repairs. Other than the separation, it is in a very nice condition, so it may be worth having it fixed. I know of these repair specialists: DAG, Youxin Ye, Ken Ruth, and Golden Touch. I assume any one of them would be able to do the job?

 

[Mike-D]

The front element on mine looks like that. Its coated and the coating, applied after manufacture presumably, is all crazed and bubbly.

 

[akptc]

Well, I asked one of the repair shops above and was told that fixing the Summar would not be worth it in terms of cost, given how inexpensively they can be had these days.

 

[Luddite Frank]

You should go back to them and inquire if they have any clean ones ( perfect glass ) for sale .... 😉

 

[John Shriver]

I improved a really wretched Summar which had major separation in the front doublet by baking the doublet in a toaster oven, to re-melt the balsam. Didn't make it perfect, but got rid of the ghost images. (Since then I got a nice one with just a bit of haze and cleaned it out, and re-blackened the glass edges.)

 

[akptc]

Do you recall the approx. temperature?

 

[Highway 61]

Judging by the second picture I'm 99.99% certain that this is the terrible fungus of the anaerobic type, which grows without oxygen, produces lactic acid as its own food, and etches the glass as well as some sandgrit paper. I have encountered the very same thing in a black Canon 50/1.8 LTM lens (a model having become famous for developing this).

My opinion is that this lens is DOA. Sad but true.

 

[John Shriver]

I think around 200 Fahrenheit. Whatever temperature is recommended to heat balsam. But first you need to remove the front lens cell (loosen setscrew in face, unscrew cow), and then separate the inner group from the front element. Then you can examine every exposed surface, to see if that's where this crud is.

 

[akptc]

I think around 200 Fahrenheit. Whatever temperature is recommended to heat balsam. But first you need to remove the front lens cell (loosen setscrew in face, unscrew cow), and then separate the inner group from the front element. Then you can examine every exposed surface, to see if that's where this crud is.

Thanks, I am very tempted to try that. Have never successfully taken a lens apart and put it back together but here it seems I have nothing to loose 🙂