Remark: This lens contains radioactive Thorium glass elements. At a distance of 1 meter the radiation level is difficult to detect over typical background levels. Thorium oxide has a crystalline structure similar to calcium fluorite. Its optical properties of high refractivity and low dispersion allows to minimize chromatic aberration and lenses of lower curvature. Thorium may cause browning of the particular lens elements (visible thru viewfinder).


