Why was thorium used in lenses?

The usage of the naturally occurring radioactive isotope thorium-232 in older camera lenses was implemented to provide better optical properties and a cheaper production.

When did they stop using thorium in camera lenses?

1980s
The production of such lenses seems to have ended in the late 1980s.

Are Helios lenses radioactive?

This lens is not radioactive.

Are Leica lenses radioactive?

Second, all Leica rangefinder cameras use a focal-plane shutter, which means the film behind the lens is shielded from the radiation it emits except for the instant the shutter is open when making an exposure, which would produce negligible fogging.

Are radioactive camera lenses safe?

Exposure to these particles over time likely presents a health risk. Until further research is done, radioactive lenses can never be considered truly safe for usage.

How was uranium glass made?

Uranium glass is glass which has had uranium, usually in oxide diuranate form, added to a glass mix before melting for colouration. The proportion usually varies from trace levels to about 2% uranium by weight, although some 20th-century pieces were made with up to 25% uranium.

Are modern lenses radioactive?

Some lenses produced from the 1940s through the 1970s were treated with radioactive thorium oxide to curb chromatic aberration. But as Andrew Walker explains in this 7.5-minute video, modern digital cameras can actually “see” that radiation as image noise that has the potential ruin your long exposures.

Are Vivitar lenses radioactive?

That lens is one of the more radioactive lenses but it’s a very long way from seriously radioactive. You’d have to try quite hard to get any radiation burns from it… Re: Is the Vivitar 90mm f2.

Are Canon FL lenses radioactive?

Lens: Canon FL 55mm f/1.2 (not radioactive)

Are Pentax lenses radioactive?

There are a significant number of lenses produced between 1940 and 1970 that are measurably radioactive, like the Pentax SMC Takumar 50mmf/1.4 lens Walker shows in the video above. Thorium Oxide is the main culprit of this radioactivity and was applied to glass elements because of its crystalline structure.

Why does uranium glow under UV light?

The uranium fluoresces under UV light because the UV excites the electrons above the ground state and gives off photons as the electrons transition back to the ground state.” Sure, everybody knows that. “The fluorescence is just an inherent property of the uranyl compound in the glass.” Natch.

Why does uranium glass glow?

As you may have guessed, Uranium glass contains uranium oxide, which gives the glass a yellow or yellow-green tint, makes it radioactive, and causes it to glow vibrantly under a UV black light…if that’s not cool on some level, we don’t know what is!