A very early collapsible Summicron 50mm f2, featuring thorium glass. Commonly known as the Radioactive Summicron. Its radioactivity has been confirmed with a Geiger counter, showing a fairly strong reading. Serial number in the 920,000 range, manufactured in 1952. Distance scale in meters. Leitz product code SOOIC.

This lens uses two thorium glass elements. As is typical of radioactive Summicrons, the glass has developed a pronounced yellow tint, which may slightly increase contrast in black-and-white photography. Comparing its rendering with later Summicrons using standard optical glass would also be a fascinating experiment.

An exceptionally well-preserved example in superb original condition, with a particularly early serial number even among the under-million Radioactive Summicrons.

This lens was originally sold by our shop and has now found its way back to us after passing through several owners. Welcome home! This will be our third time offering it for sale.

We are truly grateful to have such a rare item return to us in such wonderful condition! 🙏

Just as when we last sold it, the lens remains in beautiful condition with very little sign of use. There are only minimal marks on the collapsible barrel, and the chrome plating still shines beautifully.

Another full overhaul was carried out in 2026. Thanks to careful servicing, all controls operate exceptionally smoothly. The collapsible barrel locks into place with just the right amount of resistance, making operation effortless. Rangefinder coupling is also spot-on.

There are a few very faint cleaning marks on the front element, but the glass is remarkably clean for a Thorium Summicron. There is no haze or fungus residue, and the glass is clear and bright throughout. You can fully enjoy the sharp, crisp rendering characteristic of the radioactive Summicron.

Original front and rear caps are included.

A rare opportunity to find one in such excellent condition!