Leica 5cm (1930–1960)

At 110 grams, the original Elmar vanishes into a Leica body like it was born there — but the Summicron that followed carried a radioactive secret.

Overview

The "Leica 5cm" isn't a single lens — it's a lineage. Across three decades, Leica and its predecessor Ernst Leitz Wetzlar produced a series of 50mm focal length lenses under different names, each marking a step in optical evolution. The most legendary of these is the LEICA SUMMICRON 5cm f/2 (1953–1960), a collapsible marvel of postwar German engineering. But it stands on the shoulders of the earlier Leica 5cm f/3.5 Elmar, a design so foundational it launched 35mm photography itself. There's also the obscure Leica 5cm F3.5 Varob, reportedly an uncoated Elmar variant built for enlargers, and the rare Leica 5cm f/2 Summar — Leica’s first f/2 lens, produced from 1932 to 1939. Each variant speaks to a different era of optical philosophy, from the minimalist Cooke triplet derivative of the Elmar to the complex 7-element Summicron that redefined sharpness.

Among collectors, the Summicron commands attention — and caution. Early production models, built before 1956, contain thorium-doped glass in the front element, emitting approximately 20 µSv/h at the front. While not hazardous with normal use, it’s a quirk that raises eyebrows today. Later models, from 1956 onward, are inert. The Summicron was offered in both M39 screw mount for the LEICA IIIf and in bayonet mount for the LEICA M3 starting in 1954, bridging two pivotal camera systems. Owners report it delivers exceptional center sharpness and smooth bokeh, but its delicate front element — described as "soft as chalk" — has proven vulnerable to decades of careless cleaning. It is very unusual to find one that passes the flashlight test for haze or scratches.

The Elmar, by contrast, was never about speed. At f/3.5, it prioritized compactness, contrast, and reliability. Introduced as a fixed lens on the 1925 Leica I, it became interchangeable in 1930 and remained in production in various forms until 1961. Early versions were uncoated; from 1946 onward, anti-reflection coating became standard, along with a revised aperture scale. Though optically simpler — just 4 elements in 3 groups — it was sharp enough to produce enlargements rivaling large format cameras of the time. It collapses nearly flush with the camera body, extending only 39.25mm at infinity. At 110g, it’s less than half the weight of the Summicron, making it a favorite for travel and street photography even today.

The Summar, produced from 1932 to 1939, was Leica’s first "super-speed" lens. With a maximum aperture of f/2 and a 6-element anastigmat design, it was so advanced that Leica faced a year-long backlog after its release. It offered superior center sharpness over the Elmar but suffered from field curvature, pulling focus toward the camera at the edges. Uncoated and with a smooth, clickless aperture ring, it demanded precision from the user. Though succeeded by the Summitar in 1939, it remains a milestone in Leica’s pursuit of speed and resolution.

Specifications

Key Features

7 Elements in 6 Groups, Unique Design

The LEICA SUMMICRON 5cm f/2 broke from the Elmar’s simplicity with a 7-element optical formula, delivering superior contrast and resolution across the frame. This "unique design" — not based on the Tessar or Sonnar — allowed for better correction of spherical and chromatic aberrations, making it one of the sharpest 50mm lenses of its time. Its performance at wide apertures set a new standard for Leica, justifying the Summicron name.

Collapsible Design with Infinity Lock

All three major variants — Elmar, Summar, and Summicron — share a collapsible barrel design, allowing the lens to retract into the camera body for storage. The Summicron adds an infinity lock, a small lever that secures the lens in the extended position to prevent accidental retraction during use. This was a practical upgrade for field photographers who couldn’t afford misalignment mid-roll.

Front Element Made of Glass as Soft as Chalk

A notorious flaw of the early Summicron is its front element, made from a soft thorium-doped glass that scratches easily. Decades of improper cleaning have left most examples with swirls, haze, or edge chips. Collectors stress that original coatings and unblemished glass are exceptionally rare. The softness is not a design flaw per se — the glass was chosen for its refractive properties — but it has become the lens’s Achilles’ heel.

4 Elements in 3 Groups (Cooke Triplet Derivative)

The Elmar’s optical formula, though simple, was revolutionary in 1925. Based on a Cooke triplet but modified with an additional element, it delivered sharp, high-contrast images with minimal distortion. Its compactness and reliability made it ideal for the nascent 35mm format. Even uncoated, it performed well in backlit conditions, a testament to its design purity.

6-Blade Clickless Aperture Ring

The Summar’s aperture ring rotates smoothly without detents, allowing for continuous adjustment between f/2 and f/12.5. This design gave photographers fine control over exposure but required a steady hand. The 6-blade diaphragm produces a slightly polygonal bokeh at intermediate apertures, a characteristic some find charming, others distracting.

Uncoated Optics with A36 Filter Fit

The original Elmar and Summar were uncoated, making them prone to flare in strong backlight. However, their contrast remained high due to careful lens shaping and blackened edges. Both used A36 slip-on filters — a 36mm push-fit system — which are now rare. Later Elmar versions switched to E39 screw threads, improving filter availability.

Historical Context

The Leica 5cm f/3.5 Elmar was first introduced as a fixed lens on the 1925 Leica I, marking the birth of 35mm photography. In 1930, Leitz released the first interchangeable-lens Leica, and the Elmar became its standard optic. From 1930 to 1932, lenses were matched to individual bodies; after 1932, mounts were standardized, allowing full interchangeability. The Summar followed in 1932 as Leica’s first f/2 lens, offering unprecedented speed for available-light photography. It remained the company’s flagship normal lens until the Summitar replaced it in 1939. The Summicron, introduced in 1953, represented a postwar leap in optical design, combining speed, sharpness, and compactness in a way that defined the M3 era.

Collectibility & Value

The Leica 5cm f/2 Summar was listed at £299 in a 2018 Leica Society UK magazine, though the context — new, used, or insured value — is not specified. The Summicron, while more common, is rarely found in pristine condition due to its fragile front element. Early radioactive models are not dangerous with normal handling but may face shipping restrictions or buyer hesitation. Uncoated Elmars in working condition typically sell for less than their coated successors, though pre-war examples with nickel finish or rare hoods can command premiums. No current market prices are documented in the fact sheet, but collectors consistently report that originality and optical condition outweigh minor cosmetic wear.

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