An early collapsible Summicron 50mm f2 made with radioactive glass, commonly known as the Thorium Summicron. This example has a serial number in the 990,000 range, making it an under-million model, manufactured in 1952. The Leitz product code is SOOIC. Distance scale in feet.

Due to the radioactive glass, the lens shows some yellowing, but it is relatively mild, with only a slight color cast in actual photographs.

Many Thorium Summicrons suffer from cleaning marks and coating deterioration, making it increasingly difficult to find examples that deliver their original optical performance. This particular lens has remarkably few cleaning marks and is free from haze. A rare find in such fine optical condition!

This lens was previously sold by our shop and has now returned to us. It has been carefully used and remains in excellent condition. This will be our fourth time offering it for sale over a period of more than 10 years!

There are some minor scuffs on the base and collapsible barrel, but the chrome plating remains in very good condition, and the overall appearance is beautiful.

A full overhaul was carried out in 2024. Thanks to the careful servicing, both the aperture and helicoid still operate smoothly with a pleasant feel. The rangefinder coupling is also spot on.

There are a few extremely faint cleaning marks on the middle and rear elements, visible only under strong LED light, along with very slight coating deterioration around the edges of the middle element. None of these should have any noticeable effect on actual photographs. The original coatings remain well preserved on all glass surfaces. It is quite rare to find a Thorium Summicron in such fine condition.

You can enjoy the sharp, well-defined rendering characteristic of the Thorium Summicron. We have posted sample images in our Test Shoot Gallery, taken when we previously offered this lens for sale. Please have a look!

Original front and rear caps are included.