Summicron 50mm f2, early 2nd version, product code 11817. Commonly known as the 6-element Summicron. Serial number in the 2.29 million range, made in 1968. From this 2nd version onward, the minimum focusing distance was shortened to 0.7m. 6 elements in 5 groups. E39 filter thread.
This example has an internal construction close to the Transitional Model known from the 2.26 million serial range, which combined the newly designed 6-element, 5-group optics with the 1st-generation barrel. The red mounting index is also located on the chrome lens base. The top of the red dot is flat so that it does not interfere with the lens release button cover found on early Leica M3 bodies.
It is also a fine performer, while the removal of the infinity lock improved handling. The light-alloy barrel keeps the weight down to approximately 200g on our scale, another welcome feature.

There is slight paint loss along the front edge of the barrel and on the knurled section of the helicoid ring, but there are no noticeable scratches overall, and the barrel remains in very nice condition.
Fully overhauled in September 2026. Thanks to careful servicing, both the click stops of the aperture ring and the torque of the helicoid feel exceptionally smooth and pleasant. Rangefinder coupling is excellent, and focus is accurate.
The glass shows a few very light cleaning marks on the inner elements, as well as faint haze-like coating deterioration, but these should have no effect on actual photography. Our test shots also produced very good results.
Comes with third-party front and rear caps.