McLean Goldwhite

Yeah I agree it's not realistically much to worry about but a large part of why I enjoy shooting on film rather than digital is the experience. I like slowing down and taking my time getting to know a camera and I think it might feel a bit bad sometimes to know I'm playing a few more rounds of (albeit low risk) russian roulette with my cells while near it. I understand that some types of radiation (depending on the momentum of the particle) can pass through your body and that it has an extremely low chance to cause damage in the process. Getting material inside you that is continually emitting radiation is a much more dangerous scenario (closer to your hypothetical of glueing a radiation source to your body). I think I'm just an overly cautious person by nature who tends to look into minimizing risk so these thing come up in my consideration. ?‍♀️

Ah I see! Thanks for the diagram Simon! Still it seems that those lenses are far from the eye so that's good. If I end up picking up a 16s it would be interesting to run a geiger counter along the tube and see if it picks anything up near those elements. Your findings that it has a yellowish-brown tint means its very likely thorium. I don't know of any other additives with that distinctive color that would have been used in a lens at the time.

Thanks for all your replies! Knowing that the prism is towards the front makes me feel a lot better about picking up a 16s though I'm seeing a few good deals on newer arriflex models I might jump on. I might buy a cheap geiger counter and update this thread once I get a camera and test it. My guess is around 1970 is when they stopped using thorium but that leaves the 16bl in limbo being released in 1965 so close to the 70s. Either way it should be helpful for folks to know (either confirming that the 16s has thorium but that little to none escapes or showing that some newer model is free of thorium indicating newer than x model if thorium free).

Hey this is my first post here! I'm really just a hobbyist film photographer looking to pick up my first 16mm camera. I gravitated toward the arriflex 16s as it can be picked up for a reasonable price (often cheaper than a bolex!), takes 100' spools, has an electric motor, and has some great glass available. Unfortunately in my research I heard that they contain thorium in the prism of the viewfinder. Now I'm ok with some thorium in a lens but having it in a part of the camera I'm ment to put right up to my eye I'm a bit less comfortable with. What I'm wondering is at which model did arri stop using thorium in the eyepiece? Was it the 16m, 16bl or do I have to look all the way to the 16sr onwards? Additionally does anyone know of any options old or modern that replaces the viewfinder of the 16s, 16m or 16bl perhaps incidentally with thorium free glass? If you have one of these cameras in your possession and aren't sure about the thorium content maybe you could just let me know if looking through the viewfinder has a bit of a brownish-yellow tint? Thanks!