New old "son" in my family...

[luigi bertolotti]

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... of 5cm lenses.. ; a very old Summicron, from the first - indeed big - batch, with its distinctive yellowish coating (and the famed radioactive Kodak glass...)

 

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(taken with a much younger brother of him)

Edited September 20, 2014 by jc_braconi

[pedaes]

Congratulations! Looks really nice. Hope the rest of the family welcome him!

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[MarkP]

Amazing that there doesn't appear to be any front element scratches on such soft old glass.

Is there any hazing? If not is the development of hazing more than a function of age?

[jc_braconi]

(sorry...in the title I meant "son"...)

Luigi te l'ho coretto...facci vedere una foto presa con lui e la M

[Michael Geschlecht]

Hello Luigi.

 

Nice lens.

 

Where exactly in the lens are the "yellowish coating" & the "radioactive glass"?

 

The coated surface on the lens surface in your photo seems to have the purple/magenta coating often found in Leitz lenses of that time period.

 

Best Regards,

 

Michael

[luigi bertolotti]

Luigi te l'ho coretto...facci vedere una foto presa con lui e la M

Grazie JC.... la foto arriverà...

[luigi bertolotti]

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Hello Luigi.

 

Nice lens.

 

Where exactly in the lens are the "yellowish coating" & the "radioactive glass"?

 

The coated surface on the lens surface in your photo seems to have the purple/magenta coating often found in Leitz lenses of that time period.

 

Best Regards,

 

Michael

 

Hi Michael... I made a quick shot, and the coating is far from being well rendered... , but can assure you is quite different from the one of a similar lens of mine (1.043.366); to be honest, I decided to buy it mainly for the trivial reason that I hadn't yet any 9xx.xxx lens... ... a silly collector's craze... now have at least one lens of any Hundred-Thousand from 1xx.xxx to 2.5xx.xxx (only 2.5xxx.xxx being the Telyt S 800... ) . The dealer is trustable, but cannot swear that the front element hasn't ever been repolished...but surely not re-coated.... maybe will try to do a right picture to show the two coatings side by side...

[philipus]

Hi Luigi

 

That is a very very nice copy, congratulations.

 

It may be my screen, but it seems the metal of the front part of the lens (where the aperture ring is) has a slightly different colour than the rear part of the lens. The front part looks more modern, less shiny than the rear, which is more like, say, an old Summarit.

 

cheers

philip

[ironringer]

Thank you Luigi for sharing the picture of a very early Summicron; I assume it is a screwmount. Have you used it yet, with digital or film?

For these "radioactive" Summicrons, it is my understanding that the actual GLASS is (or becomes) yellowish, because of its chemistry using a slightly radioactive element (thorium oxide) in the "mostly-silica plus other elements" mixture, making glass with a higher refractive index. The Leica (and most European) 1940s-50s coating would appear the typical purple-blue (I don't know the chemical mixture, probably a metal fluoride). As the glass aged with radioactive deterioration, and "yellowed" over time, the original coating might appear a slightly different color.

Some early lens coatings appeared yellowish or even a deeper golden color (many USA lenses of the postwar period), so they had a different coating chemistry.

I recently received my re-coated screwmount Summicron 5 cm, serviced and re-coated (with tough magnesium flouride, appears beautiful purple-blue) by John Van Stelton at Focal Point. I am now testing this lens with Fuji 200 color print film. As you may observe from the before and after pictures, the lens glass certainly appears much improved from its original condition, after careful polishing (to remove the original coating) and re-coating in a vacuum chamber. Visible scratches are almost 100% gone (probably were mostly in the coating, not the glass) and all milky haze (under a 10X magnifier you could see thousands of tiny grease vapour droplets deposited on inner elements) is removed. And the focus and aperture rings now operate smoothly, like they should.

Expensive service but worthwhile.

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[TomB_tx]

I recently received my re-coated screwmount Summicron 5 cm, serviced and re-coated (with tough magnesium flouride, appears beautiful purple-blue) by John Van Stelton at Focal Point.... after careful polishing (to remove the original coating) and re-coating in a vacuum chamber. Visible scratches are almost 100% gone (probably were mostly in the coating, not the glass) and all milky haze (under a 10X magnifier you could see thousands of tiny grease vapour droplets deposited on inner elements) is removed.

Focal Point is a good source for this service. I sent John a similar early Summicron with front coating damage and also many "spots" on inner elements, and he advised against trying to polish and recoat, because the inner element problem was etching under the coating - a problem he has seen with the "radioactive" glass versions at times - a combination of the glass type and the early coating methods. Thus he felt any work would not improve the image quality. I appreciated his honesty, and instead spent the money to find a better condition and later glass version.

[ironringer]

Like you, I asked John to use his judgement and tell me if my lens was worth spending $400 on. He said it had no etching damage on internal surfaces, was cloudy, had surface lens scratches, and needed mechanical service (stiff rings). All problems he could fix. We decided it was worth improving, and for me it was money well spent.

He also offered (additional $150) to lap/fix the focus threads that had become rough and stiff during decades of inactivity. I declined this extra expense, and am satisfied with the much improved smooth focus action - cleaning and lubrication made an 80% improvement. "Bedding in" the threads may improve the feel over time as I use the lens.

Overall my investments in the lens ($250 on eBay) and service ($400) have resulted in a fine serviced Summicron that is probably worth more than I paid for everything, so I am happy. Now I just need to find inspiring scenes to shoot, to complete my first test roll.