Early Rolleiflex 2.8 Xenotars and radioactive glass?

[Dan Daniel]

Anyone ever heard of early Schneider Xenotars used in Rolleflexes having radioactive glass in them? I was taking apart a 2.8C. After I removed the rear group, I noticed that it was tinted yellow. I cleaned the lens group, and the color is still there-



This is a first series C, camera serial # 1255xxx. The lens is serial #3276054.

I have a couple of other C, the later 144+ serial number run. I looked through both of them (full lenses, installed in cameras) and noticed that they also have a yellow tint.

Any ideas? Glass? Or coatings? Any info? Thanks.

 

[Eric Rose]

I wonder if the cement is just yellowing? Just a wild ass guess though. Is there a concern with it being radioactive? I've heard it's no big deal. The yellow will at least give you some extra constrast

 

[Tom1956]

I doubt radioactive glass at that age. The first I ever heard of it was Takumars in the 60's. I'd say cement yellowing. Judging from the photo, a photo taken with it as it now is compared to one if it were clear would be of no noticeable difference, though. I'd put it back in and forget it.

 

[Dan Daniel]

No concern about it being radioactive. Just curiosity.

Best as I can tell about the Xenotar design, the only cemented pair is in the front group, which isn't yellow. Maybe something else has tinted the group? Considering that Schneider has has problems with its black paint on lens elements for a long time, it wouldn't surprise me if they used something that gassed off or such.

 

[Tom1956]

My 3.5 Xenotar on my Rollei 3.5E has a single non-cemented front element.

 

[JW PHOTO]

Three elements in the front group and two are cemented. Two single elements in the rear group and no cement. The later six element lens has three elements in the rear group and two cemented. It also has three elements in the front group with two cemented. JW

 

[snapguy]

Suggestions

Firstly, the lenses do not look yellow to me. One looks like it has too much blue. There seems to be at least two light sources falling on the lenses and from the reflections I assume an ordinary light fixture provided some of the light. I assume you did not use a Color Temperature Light Meter when you prepared to take the photo. Now the question is -- how do you get from off-color light sources to radioactivity?

 

[Dan Daniel]

Firstly, the lenses do not look yellow to me. One looks like it has too much blue. There seems to be at least two light sources falling on the lenses and from the reflections I assume an ordinary light fixture provided some of the light. I assume you did not use a Color Temperature Light Meter when you prepared to take the photo. Now the question is -- how do you get from off-color light sources to radioactivity?

Oh, the rear group is yellow alright. The photo isn't a scientific document, just a rough illustration.

The answer is that I didn't go from off-colored light sources to anything. I've been doing paint and ink and product manufacturing color matches for 30 years. I know how to separate the various issues that affect how a color is perceived. Pretend the photo isn't there; what makes some glass have a yellowish tint? I'm open to learning.

 

[BrianShaw]

If it were on the outside element I'd suggest smoker's film. But since it is inside I have no idea. But it may serve a good purpose as a built-in haze filter.

 

[BrianShaw]

Oh... and is that Schneideritis, or an artifact of the photography?

 

[Dan Daniel]

Oh... and is that Schneideritis, or an artifact of the photography?

Yep, Schneideritis. Not sure how Schneider spent a decade or two at least never solving that problem.

Which hints at another possible source of the yellow- some material used in manufacturing which gassed off onto the lens(es). Paint, sealant, who knows.

 

[BrianShaw]

Which hints at another possible source of the yellow- some material used in manufacturing which gassed off onto the lens(es). Paint, sealant, who knows.

Dunno, never saw anything like that before. If it were a manufacturing or materials issue you'd think it would be a better known phenomenon. It's not like they didn't make a lot of them. Could just be some one-off problem for that particular camera. Weird things happen sometimes that defy explanation.

 

[Christiaan Phleger]

Looks like the classic look of a lens with Thorium in the mix. The Takumars were not the earliest; the famous Kodak Aero-Ektar was the first as far as I know, and that most assured
has the Thorium/Radioactive glass. Highly likely. The only way is to test with a proper Gieger counter. This is the first I've heard of this lens being radioactive but it sure looks this way.

 

[Christiaan Phleger]

Oh and I have a Zeiss Planar 80mm 2.8 mounted in shutter covers 6x9 that is yellowed/radioactive from this era, so I don't have any doubt that the German optical leaders were using it in their top lenses.

 

[Dan Daniel]

Oh and I have a Zeiss Planar 80mm 2.8 mounted in shutter covers 6x9...

Really?? Oh my... That must be a wonderful shooter. Was it made special for 6x9, or is it a 'standard' Planar?

The lens under discussion here came on a Rolleiflex 2.8C in very good mechanical condition. And the lens is flawed in may ways- coating speckles, a gouge in the front element, some separation, lots of dust, etc. I bought the camera to swap over a fantastic Xenotar on a mechanically weak 2.8C body. I figured I'd give this flawed Xenotar a shot on my 6x9 so I've mounted it to a shutter and plan to test it when the rain stops. I wonder what kind of coverage I'll get.

 

[Christiaan Phleger]

Yum that sounds like a good plan for a great lens although in rough shape. Love to see what you get; what shutter did you mount it in?
I'm pretttttyyyy sure what you've pointed out is radioactive; we won't know until you test it. Hint Hint.

You can push those Planar/Xenotar designs fairly far, they were good designs although only really excellent in the intended zone of resolution. (Especially if it has the advantages of the Thorium glass).

I'm pretty sure mine is designed to make 6x7 and perhaps 6x9; it came mounted in correct shutter already mounted on a Baby Graphic lens board, from a former wedding photographers estate so I'm fairly confident that the lens was/is being used as intended on the proper camera, and 6x9 was a standard option for that camera. I've contacted Zeiss and they could not give me any further information other than what I've found.
Here's a frame from the lens at 2.8 on 6x9, I've enhanced the vignetting for effect, in practice it has less.
http://four-silver-atoms.com/2012/01/09/wind-shift/

 

[Dan Fromm]

In his article on LF lenses from Zeiss Oberkochen (download it from http://www.arnecroell.com/publications), Arne Croell mentions that Xenotars were made with thorium glass. He gives the 80/2.8 Planar's coverage as 100 mm, i.e., 2x3 and not a millimeter more.

I have an 80/2.8 Xenotar in Compur #00 that's in horrible condition. It doesn't illuminate 2x3. I don't think its poor condition has anything to do with that. Let's not even think about it covering; I also have an 80/2.8 Planar obtained as cells from Edmund Scientific, supposedly ex-Graflex, that certainly illuminates and may cover 2x3. I've never used it, just looked through it.

 

[Dan Daniel]

Thanks, Dan Fromm. Interesting to follow a link to a forum discussion saying that Schneider used thorium in glass into the 1970s. Learn something new every day. (Are you sure about the #00 shutter size? That's the Tessar f/3.5 ando ther small lens shutter size; the Rollei uses a #0 for the 2.8 lenses.)

Someone on another forum is going to test his Xenotar with a geiger counter next week. I'll let people know if it is hot.

RW, I put the lens in an old Linhof Synchro-Compur shutter (#0 size), 10-bladed version similar to the Rollei shutter.. I have a 6x7 back for my 6x9 Horseman; I expect I'll be using that with the Xenotar but first I will try 6x9 to see what it can cover.

Nice tone and light on the wedding shot.

 

[pgomena]

Hmm, I own a 2.8C with Xenotar. I'm going to have to look through the lens once I've used up the film. Not that I'll do anything about it, but it's interesting.

 

[Tom1956]

I wouldn't give it another thought. I'd put that sucker back in the camera in a heartbeat. Yessireebob.

 

[Dan Fromm]

Thanks, Dan Fromm. Interesting to follow a link to a forum discussion saying that Schneider used thorium in glass into the 1970s. Learn something new every day. (Are you sure about the #00 shutter size? That's the Tessar f/3.5 ando ther small lens shutter size; the Rollei uses a #0 for the 2.8 lenses.)

Thanks for asking. I just checked, was mistaken (memory failure). It is in a #0.

 

[Dan Daniel]

I wouldn't give it another thought. I'd put that sucker back in the camera in a heartbeat. Yessireebob.

But I hold the TLR near my face, and that lens is pointing right at my thyroid gland!!!! I have a family history of thyroid issues. Shouldn't I be worried????

 

[Dan Fromm]

http://home.earthlink.net/~michaelbriggs/aeroektar/aeroektar.html

 

[EdSawyer]

I have a large-format xenotar that exhibits fine traces of yellowing,so I think they used radioactive glass in the later/larger ones also.

 

[Christiaan Phleger]

Dan Fromm that information about the Zeiss's matches my experience, 2x3 coverage and not a millimeter more, forget any movements. I prefer it used as a 6x4.5 lens mostly.