Leica Summicron-C 40mm f/2

Look on the front of a Summicron-C and you will find a thread, 39 x 0.75 mm, that invites the wrong assumption. The diameter matches Leica's E39 filters while the pitch does not, and forcing an E39 filter onto it can ruin the thread for good. That thread is there to carry the rubber hood. Leitz expected you to drop a Series 5.5 filter into the hood and screw the whole assembly down, so the filter travels with the hood, and if the hood stays home, the yellow filter stays with it. Series 5.5 glass was already scarce when Jörg-Peter Rau reviewed the lens for Macfilos in 2021: B+W had dropped the size, and Heliopan was still making it in 2020.

Leitz built it in Germany from 1973 to 1979 as the standard lens for the Leica CL, order number 11542, with six elements in four groups and a ten-blade diaphragm. On the CL a 40mm frame sits in the finder permanently. Put it on an M and the lens calls up the 50mm lines instead, because M bodies have no 40mm frame, so the negative always holds more than the frame showed. You learn to compose a little tight.

The coupling is what worries buyers. Leitz itself warned that the inclined focusing cam might not couple precisely with an M-body rangefinder. Plenty of owners report no trouble, and Rau's copy focused accurately on an M10 wide open at close range, which is where a mismatch would show first. Minolta's 1981 CLE-era Rokkor 40mm switched to a conventional parallel cam, but the Summicron-C was out of production by then. If you are buying one for an M, check it at f/2 near the 0.8 m minimum before the return window closes.

Rau found it a touch soft wide open and at that minimum distance, then crisp from f/4 on. He also shot it on a snowy day in the Swiss Alps, then with the sun at deliberately awkward angles, and the early-1970s single coating held up better than he expected. The background is where opinions split. The out-of-focus rendering has its critics, and the bokeh draws regular criticism, though Rau did not think it was that bad.

At 120 g, reaching only 23.5 mm out from the flange, it barely registers on an M body, and that changes how you use the camera. It stays mounted for walks and errands and unplanned frames. The focusing throw is short; a Japanese reviewer who shoots one on an M typ 240 found it quick enough for animals that move without warning. The same smallness is the honest weakness. The aperture ring and focusing lever are tiny, the Macfilos review named handling as the real drawback, and big fingers or gloves will fumble them.

Leica Wiki listed a street price of about $350 in 2010. People still cross-shop it against the Minolta, and that Japanese reviewer reckons the Leitz version costs two to three times as much. The premium buys German manufacture and the Leitz Wetzlar engraving, along with a hood-and-Series filter system that some owners curse and others quietly enjoy. Black-and-white shooters with a Series 5.5 yellow or orange under the hood have a filter factor to account for. The CL's through-the-lens meter reads through the filter; on an unmetered M, pick the filter in Zone Light Meter and the shutter speed and aperture it suggests already include the factor.