Is the Summilux-R 35/1.4 radioactive?

[John Jovic]

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Is the Summilux-R 35/1.4 radioactive, does it have any radioactive dopants?

I've recently started using a Summilux-R 35/1.4 again (I've owned it for 30 years) and noticed it has a noticeably warm colour rendition compared with other lenses (of various brands, not just other Leica R lenses).

I have a few vintage radioactive lenses and am used to the warm colour cast these lenses can sometimes cause but I haven't noticed this on the Summilux-R 35/1.4 until recently. I'm using it on Sony bodies. I haven't found anything online to suggest it has radioactive dopants but am curious to know if anyone else has experienced this with this lens.

 

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Edited February 20 by John Jovic

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[Warrent Sattunyue]

The most reliable way to determine whether the lens is radioactive is by measuring it with a Geiger counter .
Radioactive Lenses and Everything About Them!  https://lenslegend.com/radioactive-lenses/
https://www.facebook.com/share/p/15qyDLWdJt/
 

[John Jovic]

1 hour ago, Warrent Sattunyue said:

The most reliable way to determine whether the lens is radioactive is by measuring it with a Geiger counter .
Radioactive Lenses and Everything About Them!  https://lenslegend.com/radioactive-lenses/
https://www.facebook.com/share/p/15qyDLWdJt/
 

Thanks, I'm fairly sure it's not radioactive else there would have been mention on the net, surely. And I don't have a geiger counter, and unlikely to buy one.

I'm curious to understand why I am getting warm images, radioactive elements is one option, or is this common with this lens. Maybe not. Maybe the Sony bodies I'm using are not properly correcting white balance. I shoot raw so it's not a big deal, but why is it happening?

[Eclectic Man]

Radioactive elements were discovered by keeping a rock containing Uranium in a drawer with an unexposed photographic plate.  When the plate was developed and fixed, there was an image of the shape of the rock that had been left on top of it.  So if you are really interested you could always leave it in a dark drawer with some high ISO unexposed film and find out without actually buying a Geiger counter.

[chris_livsey]

“The optical properties of old classic lenses won’t likely be replicated in the near future or ever, for that matter. Lead, Lanthanum and Thorium glass production were halted as of 2001."

Rare Earth Glass Leica Lenses: A Quick and Quirky Overview — LSI - Leica Society International

Production of the 35mm f/1.4 Summilux-R was  - 1984-2009

35mm f/1.4 Summilux-R - Leica Wiki (English)

So at the end, 2009, was well past the production dates of radioactive glass elements and there is no note of any change in the optical formula, unlike for example 38mm (Zeiss) Biogon in the (Hasselblad) SWC which would have been necessary.

For pedants that was changed twice, it was changed in 1986 (SWC with CF lens) to use new glass types, removing the radioactive elements and more radically changed in 2001 (905SWC with CFi lens) to eliminate arsenic and lead in the glass.

 

[John Jovic]

7 hours ago, chris_livsey said:

“The optical properties of old classic lenses won’t likely be replicated in the near future or ever, for that matter. Lead, Lanthanum and Thorium glass production were halted as of 2001."

Rare Earth Glass Leica Lenses: A Quick and Quirky Overview — LSI - Leica Society International

Production of the 35mm f/1.4 Summilux-R was  - 1984-2009

35mm f/1.4 Summilux-R - Leica Wiki (English)

So at the end, 2009, was well past the production dates of radioactive glass elements and there is no note of any change in the optical formula, unlike for example 38mm (Zeiss) Biogon in the (Hasselblad) SWC which would have been necessary.

For pedants that was changed twice, it was changed in 1986 (SWC with CF lens) to use new glass types, removing the radioactive elements and more radically changed in 2001 (905SWC with CFi lens) to eliminate arsenic and lead in the glass.

 

Thanks. Given that the lens was introduced in 1984 it's extraordinarily unlikely to have any radioactive dopants. My issue is that I can't otherwise explain the very warm cast I get from this lens (admittedly on digital bodies where the white balance is being determined by an algorithm which doesn't always get it right anyway, and is another reason to shoot RAW).

[chris_livsey]

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It is a conundrum, I see no evidence of a generic effect in the gallery here: https://www.flickr.com/groups/leica_summilux-r_14_35mm/pool/with/28068370161

I think, unless you have a particular reason not to, RAW and manual balance is your answer.

 

 

Edited February 27 by chris_livsey
removed reference to M lens variant on a Sony

[davidmknoble]

Many of the R lenses had coatings that were ‘orange’ in color.  I am confident that is the case here.  The R glass, as you likely recall, was made for color transparency film and so it has some special renderings with today’s sensors, which are not the same as film.  Your image is of a beautiful copy of that lens.