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Summicron-C 40mm f/2

Ernst Leitz · Leica M · 1973 · Double Gauss

Also known as: Leitz Summicron-C 40mm f/2 · Leica Summicron-C 40 · Summicron-C 1:2/40 · 11542 · ズミクロンC 40mm F2

Variants & identification

Variant Mount Years Serial ranges Production
Summicron-C 40mm f/2 (11542) Leica M 1973–1979 2507601–2509600
2550551–2554550
2558551–2568550
2590501–2600500
2630601–2640600
2674701–2679700
2703801–2708800
2718651–2721000
2741631–2747630 		54,350 serial numbers assigned across nine blocks, 1972–75 (Leica Wiki)
  1. Who designed it is the open question on this page, and the sources do not converge. Thorsten Overgaard names four Leitz optical designers — Georg Knetsch, Hermann Desch, Heinz Marquardt and Walter Watz — and gives no citation for the list. Mike Eckman's history of the camera states the opposite: that the 40mm was designed entirely by Minolta and only the 90mm Elmar-C was a Leitz computation. The Leica Wiki's index of Leitz designers, which credits Wilhelm Albert with the CL body itself, attaches no name to either C lens, and its list of Walter Mandler's designs — the obvious guess for a 1970s Leitz lens — does not include them. No name is carried in the designers field, because none of the three positions is supported well enough to state as a credit.
  2. The four names do not survive a check against the index they appear to come from. Overgaard gives each man a second credit in brackets — Desch "also 21mm and 28mm Elmarit", Marquardt "also 60mm Macro-Elmarit-F, 28mm Elmarit-M and 50mm Summilux-R", Watz "also 35mm Summilux-M and 35mm Summilux-M Aspherical AA" — and those bracketed credits are, near enough word for word, the entries beside those men on the Leica Wiki's designer index. That index also gives each man a span of active years: Desch 1961–1970, Marquardt 1961–1968, Watz 1990. None of the three spans reaches 1973. Georg Knetsch does not appear on the index at all. The list is therefore not merely uncited; it is inconsistent with the one document its supporting details track, and that document attaches no designer to this lens.
  3. Where it was built is a separate question from who computed it, and it has a firmer answer. The barrel is engraved LEITZ WETZLAR, the Leica Wiki gives the housing as black chrome-plated brass, and the write-ups that address manufacture put the Leitz-badged lens in Germany. The line often quoted against that — camera-wiki's and English Wikipedia's "it is said that the 40mm was made in Japan by Minolta while the 90mm was made by Leitz" — sits inside the paragraph about the Leitz Minolta CL and the M-Rokkor-badged lenses, and cites two sites about Minolta rangefinder lenses. One of those two, the Manual Minolta site, is explicit where Wikipedia is loose: "All of the 40mm lenses marked 'Rokkor' were made in Japan by Minolta, while the 40mm 'Summicron-C' lenses were made in Germany by Leitz." Read against its own source, the sentence is a statement about the Rokkor, not about the Summicron-C.
  4. The 54,350 is a count of numbers, not of lenses. Overgaard rounds it to 54,000 and calls it lenses produced between 1973 and 1979; the Leica Wiki's own table, compiled from known lenses and Erwin Puts's Pocket Pod, dates the nine blocks 1972–75. No production record for this lens has been published.
  5. Filters are described two ways and both appear to be true of the same barrel. The Leica Wiki's specification line reads "39mm x 0.75mm 5.5 series"; Mike Eckman describes a rubber hood screwed into a 39mm filter ring; retailers and reviewers usually list the lens as Series 5.5 and call the thread awkward. The practical position, stated by more than one reviewer, is that a 39mm filter will start on the thread and should not be forced.
  6. The 40mm frame is permanently displayed on the CL because the Summicron-C carries the same cam as a 50mm lens; mounting a 90mm swaps the 50mm frame for the 90mm one. On any other M body the lens therefore brings up the 50mm frame, which is tighter than what it actually covers. The common answer is to pull the frame-selector lever and use the 35mm frame instead, which several reviewers report is close to the real coverage.
  7. A third CL lens exists and almost nobody has seen one. The Elmarit-C 40mm f/2.8, order number 11541, was built and never officially released; the Leitz Photographica catalogue describes it as about 400 pieces. Serial 2512983, dated 1972, was offered in mint condition with both caps against an estimate of €2,600–3,000 and went unsold. An earlier sample in the same catalogue carries no serial at all, is engraved on the front with the optical design number B771, and has a different mount and focusing lever from the production lens.
How to tell them apart (expand)
  • 40mm, not 35mm or 50mm — the only 40mm lens Leitz ever sold as an interchangeable lens
  • A sloped rangefinder cam cut for the CL, not the flat cam of an ordinary M lens
  • Filter mounting quoted two ways: a 39 × 0.75mm thread, and Series 5.5 slip-on

Summicron-C 40mm f/2 (11542):

  • Front ring engraved LEITZ WETZLAR with the serial, then SUMMICRON-C 1:2/40
  • A curved focusing tab under the barrel, reachable with one finger

Serial-range notes

the block, not the lens — how to read the Leitz list
The same rule that governs the bodies. Leitz allotted blocks of numbers to a product and dated the allotment, not the lens; a number gives the block it falls in and the earliest date that block could have been used. The Summicron-C's nine blocks total 54,350 numbers, which is a ceiling on how many were built rather than a count of them.
2507601–2509600
The first block, dated 1972 in the Leica Wiki's table — a year before the CL was announced. Allocation running ahead of manufacture is ordinary in this list and is not evidence of an earlier lens.
2741631–2747630
The last block, 6,000 numbers dated 1975. The Leica Wiki's summary line nonetheless gives the production era as 1973–79, four years past the final allotment; no source consulted explains the gap.

Specifications

Formula
Double Gauss
Construction
6 elements / 4 groups
Aperture range
f/2–f/16
Diaphragm blades
10
Min. focus
0.8 m
Dimensions
23.5 mm long
Weight
120 g
Filter
39 mm (0.75 mm pitch)
Years manufactured
1973–1979
Country
Germany
Material
Black chrome-plated brass

What reviewers say

History

The CL’s finder shows frames for 40, 50 and 90mm, and the 40mm frame is the reason this lens exists at that focal length. A rangefinder that small cannot honestly show a 35mm frame — the frame would run off the edge of the eyepiece — so Leitz set the widest frame at 40mm and built a lens to fill it. It remains the only 40mm lens the company has ever sold as an interchangeable lens; the other Leica 40, the f/2.4 Summarit of 1995, is built into the front of the minilux and cannot be taken off it.

It is a small lens by any standard: 120 grams, 23.5mm from the flange, six elements in four groups, ten blades, focusing to 0.8m. Its reputation has held for fifty years, though the superlatives attached to it are impressions rather than tests: Mike Eckman calls it likely the sharpest lens ever made at this focal length and immediately allows that it may not be, and nobody consulted has measured it against the rest of the 40mm field.

The interesting thing is not the optics. It is that nobody can say for certain who computed them. Thorsten Overgaard’s page names four Leitz designers — Knetsch, Desch, Marquardt and Watz — without citing where the list came from. Mike Eckman’s history of the camera says flatly that the 40mm was designed entirely by Minolta and that only the 90mm Elmar-C was a Leitz computation. The Leica Wiki’s own index of Leitz designers, which is happy to credit Wilhelm Albert with the CL body, gives neither C lens a designer at all, and the lens does not appear on Walter Mandler’s list either. Those three positions cannot all be right, and no source consulted reconciles them.

Overgaard’s list is the weakest of the three, and it can be checked. Each name on it carries a bracketed second credit, and those brackets reproduce the Leica Wiki designer index almost word for word — which is also where that index gives each man his working years. Desch is listed there 1961–1970, Marquardt 1961–1968, Watz at 1990; none of those spans contains 1973, and Knetsch is not on the index at all. So the one document the list appears to have been built from both fails to place three of the four men in the right decade and declines to name a designer for this lens. That is not a reason to hand the credit to Minolta instead; it is a reason not to print any of the four as a fact, which is why the designers field on this entry is empty.

Manufacture is the easier half. The front ring says LEITZ WETZLAR, the housing is black chrome-plated brass, and the accounts that address the question put the Leitz-badged lens in Germany. The sentence people quote against that — camera-wiki’s “it is said that the 40mm was made in Japan by Minolta” — appears in the paragraph about the Leitz Minolta CL and cites two pages about Minolta rangefinder lenses. One of them, the Manual Minolta list, says it without the hedge and without the ambiguity: the Rokkor-marked 40mms were made in Japan by Minolta, the Summicron-C-marked ones in Germany by Leitz. The sentence is describing the M-Rokkor. Whether the two lenses share a computation is the argument on that lens’s page, not this one.

Two practical notes for anyone buying. The filter mounting is quoted as both a 39 × 0.75mm thread and Series 5.5, and both descriptions appear to fit the same barrel; a 39mm filter starts on the thread and should not be forced. And on any M body other than the CL, the lens brings up the 50mm frame, which is tighter than the picture it takes — pulling the frame-selector lever to the 35mm frame gets much closer.

One more lens belongs in the footnote. An Elmarit-C 40mm f/2.8, order number 11541, was built and never released; the Leitz Photographica catalogue puts it at about 400 pieces, and a mint 1972 example failed to sell against a €2,600–3,000 estimate. An earlier sample in the same catalogue has no serial number and carries the optical design number B771 engraved on the front, which is about as close as this family gets to a factory document.

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This history is AI-written, from the sources listed at the foot of the page. Where the record is silent it says so rather than filling the gap — but no human wrote these sentences.

Example photos

Sample photo wanted — shot with a Summicron-C 40mm f/2? We'd love to feature it (with credit).

Live listings

Asking price, USD: a median of $1,100 across 28 fixed-price listings on 2026-09-11 (middle half $870–$1,400). Tracked since 2026-09-06, 2 days: unchanged from $1,100.

By day
DateMedianMiddle halfListings
2026-09-11$1,100$870–$1,40028
2026-09-06$1,100$870–$1,40028

Asking prices from the listings scanned, not sales; junk-flagged rows and auction lots excluded; other currencies are not converted.

Show 48 more listings

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Listings updated 2026-09-11. Links go to the shop or marketplace that carries the item.

Related: Elmar-C 90mm f/4 · M-Rokkor 40mm f/2 · M-Rokkor 90mm f/4

Sources (12)

Every page here is assembled from public sources, and the gaps are real ones. If you own this lens, know a serial number I'm missing, or can see where I have it wrong, tell me — corrections, serials and sample photos are all worth having.