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Radioactive viewfinders on the Eclair ACL


Eric Niemi

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On 8/22/2021 at 1:35 PM, Doug Palmer said:

Thinking about the cameras and lenses, surely the manufacturers would have considered the detrimental effect on the film itself ? Even if no thought for camera operators ?

in practice, radioactivity in a viewfinder does not affect the film at all.  In the taking lens the radioactivity could probably affect a stills frame if you have very sensitive film and leave it in the camera for months without shooting more frames so that the one frame would be exposed for many months and there is only the mirror and the shutter curtains to block radiation. I would say that it is impossible to see any difference in moving film no matter how sensitive the film stock would be. the radiation level is just too minimal and the exposure time too short for it to affect the stock enough to make a visible difference

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The Geiger counter has arrived! And here are the results... Disclaimer: I'm not a professional, this is actually the very first time I use a Geiger counter and my setup is not a lab setup. This is not medical advice, your mileage may vary etc.

I have tried to take several measurements to avoid having some surge of radioactivity (for example, due to radon) affect the readings.

This counter doesn't detect alpha particles. However, thorium decay causes also beta and gamma radiation, so should there be such radioactive elements, I'm convinced my counter would detect it.

Background radiation today in Tampere, according to Säteilyturvakeskus: 0.161 µSv/h

Room BG levels: 0.10-0.18 µSv/h (highest counts when counter on the wooden table...)

Switar 10mm f1.6: 0.16-0.18 µSv/h

Switar 16mm f1.8: 0.25-0.34 µSv/h (rear)

Angenieux 6-80mm f1.2: 0.14-0.21 µSv/h (rear)

Angenieux 9.5-57mm f1.6-2.2: 0.10-0.23 µSv/h (rear)

The results with these lenses make me believe that only my Switar 16mm is more radioactive than other stuff around me. Only its readings stayed consistently over the background radiation levels.

And now *drum rolls* 

ACL 1.5 Angenieux orientable VF: 0.10-0.18 µSv/h

..... Ground glass: 0.12-0.15 µSv/h

In order to get the readings I set the VF diopter to -5 (minimum extension) and removed the eyecup to get the counter close to it. I tried different orientations of the counter as I'm not totally sure where the tube in it is. But results: nothing. No bursts of clicks.

I think we can conclude that at least this particular VF doesn't contain thorium or other radioactive elements.

The ACL 2 Kinoptic VF on the other hand ... ? Just joking. I don't have one to test, as I made the mistake of selling it for pennies four years ago. Perhaps you could put together an .. ehm .. fundraiser to buy me an ACL 2, I could then test it for you ?

...or perhaps just get a Geiger counter yourself, probably cheaper ?

Still, I would be quite surprised if the Kinoptic - which is newer than Angenieux - had thorium. That's already from the turn of 70s and 80s.

That would leave the oldest, non-orientable viewfinders. I really don't believe those have thorium in them either.

And NPR viewfinders? Well, those are from the 1960s. Closer to Arriflex 16S in age. But has anyone checked with a Geiger counter even those? Thus far the only evidence for thorium in Arriflex I have seen is the mention of the color of the glass - and that yellowness is not really evidence, unless UV light treatment makes the glass clear again - or so I have understood. Clear glass can be thoriated and yellow glass can be yellow due to other reasons.

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38 minutes ago, Heikki Repo said:

I tried different orientations of the counter as I'm not totally sure where the tube in it is.

 

if it is the same model than I have, then the geiger tube is on the bottom part of the meter where you see small "ventilation slots" on the plastic. if watching carefully you may see the tube surface through these small slots/openings. the meter is meant to be installed on a wall like a thermometer and thus the tube is on the bottom part so that it is towards ground or floor

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42 minutes ago, Heikki Repo said:

And NPR viewfinders? Well, those are from the 1960s. Closer to Arriflex 16S in age. But has anyone checked with a Geiger counter even those?

I highly doubt it. Most people tend to not really test these things so that they can justify why they don't need to shoot anything with the camera (they can always reason that they THINK the camera MIGHT be radioactive and thus they can't shoot anything with it... instead of admitting that they don't want to shoot with the camera because it is "expensive" and "difficult" ) ?

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26 minutes ago, aapo lettinen said:

if it is the same model than I have, then the geiger tube is on the bottom part of the meter where you see small "ventilation slots" on the plastic. if watching carefully you may see the tube surface through these small slots/openings. the meter is meant to be installed on a wall like a thermometer and thus the tube is on the bottom part so that it is towards ground or floor

Okay, I retested that way both the VF and the Switar: VF, nothing. Switar 16mm: 1.03 µSv/h. Don't hold that on your eye.....

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29 minutes ago, aapo lettinen said:

I highly doubt it. Most people tend to not really test these things so that they can justify why they don't need to shoot anything with the camera (they can always reason that they THINK the camera MIGHT be radioactive and thus they can't shoot anything with it... instead of admitting that they don't want to shoot with the camera because it is "expensive" and "difficult" ) ?

Well, for someone who has tendency towards OCD such things do matter, it's not just some excuse. Some of us just tend to get affected by news stories of brain eating amoebas, knowledge of possible radiation and lead from solder (getting eaten by toddlers) ? 

And then there are those of us, who have no issues with storing photographic chemicals on kitchen table, right next to food...

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31 minutes ago, Frank Poole said:

@Heikki RepoThanks so much for posting your results!! Never would have known my beloved little Switar 16mm 1.4 was f'ing radioactive ? 

The Swiss secrets! ? But surprisingly the 10mm isn't, so not all Switars are radioactive. f1.4  seem to be, since that has been reported on this forum in the past... ?☢️

Edited by Heikki Repo
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10 hours ago, Heikki Repo said:

And now *drum rolls* 

ACL 1.5 Angenieux orientable VF: 0.10-0.18 µSv/h

..... Ground glass: 0.12-0.15 µSv/h

In order to get the readings I set the VF diopter to -5 (minimum extension) and removed the eyecup to get the counter close to it. I tried different orientations of the counter as I'm not totally sure where the tube in it is. But results: nothing. No bursts of clicks.

I think we can conclude that at least this particular VF doesn't contain thorium or other radioactive elements.

Does it look yellowish when you look through the viewfinder?   My CP16R version has a slight yellow tint. 

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13 hours ago, Robino Jones said:

Does it look yellowish when you look through the viewfinder?   My CP16R version has a slight yellow tint. 

Well, for some reason I feel it did look yellowish when I first got this camera but after Bernie did the laser brightening and also redrew the ground glass markings, it doesn't look yellow anymore. Can't say if the yellowness was in the vf or ground glass.

Anyway, I find it hard to believe Angenieux would have used radioactive elements in viewfinders in the 1970s. I know only of Angenieux 15-150mm that has such radioactive lensing inside it (a friend, old DP told visiting a nuclear facility with it would set off alarms). But even my Angenieux 9.5-57mm for 16mm or the high end super-8 zoom with f1.2 doesn't contain any - and those rare earth minerals are really useful in the taking lens, because that affects the image on the film.

So if even most of the professional lenses of the era made by Angenieux don't contain radioactive elements, why would they have used them in the viewfinders, where it is a) forbidden and b) not really that useful?

My guess is that yellowing is due to something else. Could be as simple as cigarette smoke...

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8 hours ago, Heikki Repo said:

 

Anyway, I find it hard to believe Angenieux would have used radioactive elements in viewfinders in the 1970s. I know only of Angenieux 15-150mm that has such radioactive lensing inside it (a friend, old DP told visiting a nuclear facility with it would set off alarms). .

Gosh !

8 hours ago, Heikki Repo said:

 

My guess is that yellowing is due to something else. Could be as simple as cigarette smoke...

Maybe... my Steenbeck was completely yellow when I bought it, including the lenses.  It smelt a lot too.

Edited by Doug Palmer
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  • 9 months later...

I have now tested every iteration of Eclair ACL viewfinders there are: The early small Angenieux, the small Kinoptik that came next, the orientable Angenieux and the orientable Kinoptik. Nothing. My Geiger counter doesn't detect alpha particles, but as evidenced by the Switar that had slightly radioactive elements in it, there would be beta particles as well if the viewfinder lenses had radioactivity.

I really wonder where this rumor came originally from, but it doesn't seem to be based on any reality.

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  • 2 years later...

Hi everyone,

I've got an ACL 2 Kinoptik fully orientable viewfinder. It's yellowed. Now, in a hack attempt I tried blasting it with UV from the sun and from a lamp but the yellowing never faded. So it's still a question whether it's radioactive or not. The yellowing could be from something else.
But I've ordered a radiation meter. Any ideas as to what else the yellowing could be? It may be that although Heikki's tested every model, it's still that some of the viewfinders contain radioactive elements and some don't.
Once again, we'll see.

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11 hours ago, Noah Giddings said:

Hi everyone,

I've got an ACL 2 Kinoptik fully orientable viewfinder. It's yellowed. Now, in a hack attempt I tried blasting it with UV from the sun and from a lamp but the yellowing never faded. So it's still a question whether it's radioactive or not. The yellowing could be from something else.
But I've ordered a radiation meter. Any ideas as to what else the yellowing could be? It may be that although Heikki's tested every model, it's still that some of the viewfinders contain radioactive elements and some don't.
Once again, we'll see.

Most likely the rumour has started because of the yellowing, but I very much doubt there are any radioactive elements in any viewfinder. Why? First of all, these viewfinders are rather recent, the fully orientable Kinoptik from the late 1970s / early 1980s. For example, even the last shoe-fitting fluoroscope devices were banned in the West Germany by 1973. There was already then awareness of harms of radiation (even if it took until 1989 in Switzerland to ban them). Furthermore, radioactive elements are expensive to put in a lens - they are rare even in the Angenieux cine lenses and those are for imaging, not just for framing purposes.

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