Radioactive lens (SMC Takumar 55/1.8) measured with Polaron-Pripyat and RKSB-104 dosimeters
large radioactive camera lens (thorium 232)
by adding thorium to the lens glass, a high refractive index could be achieved while maintaining a low dispersion. thus, radioactive camera lenses used to be state-of-the-art in high-demand photography.