Leica 5cm (1930–1960)

At 110 grams, the original Elmar sits in a Leica body like it was made for it. The Summicron that followed carried a radioactive secret.

Overview

The "Leica 5cm" is not one lens. It is a line of 50mm lenses that Leica and its predecessor Ernst Leitz Wetzlar built across three decades under different names. The best known is the LEICA SUMMICRON 5cm f/2 (1953-1960), a collapsible lens of postwar German engineering. It follows the earlier Leica 5cm f/3.5 Elmar, the design that launched 35mm photography. There is 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. The Elmar is a minimalist Cooke triplet derivative. The Summicron is a complex 7-element design that redefined sharpness.

Collectors treat the Summicron with attention and some caution. Early production models, built before 1956, contain thorium-doped glass in the front element, emitting approximately 20 µSv/h at the front. That is not hazardous with normal use, but it raises eyebrows today. Later models, from 1956 onward, are inert. The Summicron came in M39 screw mount for the LEICA IIIf and in bayonet mount for the LEICA M3 starting in 1954. Owners report exceptional center sharpness and smooth bokeh. The front element is described as "soft as chalk" and has suffered from decades of careless cleaning. It is very unusual to find one that passes the flashlight test for haze or scratches.

The Elmar was never about speed. At f/3.5, it prioritized compactness, contrast, and reliability. It was introduced as a fixed lens on the 1925 Leica I, became interchangeable in 1930, and stayed 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. The design is simple, just 4 elements in 3 groups, but 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 weighs less than half what the Summicron does, which makes it a favorite for travel and street photography even today.

The Summar, produced from 1932 to 1939, was Leica’s first "super-speed" lens. It had a maximum aperture of f/2 and a 6-element anastigmat design, and it was so advanced that Leica faced a year-long backlog after its release. It was sharper at the center than the Elmar but suffered from field curvature, pulling focus toward the camera at the edges. It was uncoated and had a smooth, clickless aperture ring, so it demanded precision from the user. The Summitar succeeded it in 1939.

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" was not based on the Tessar or Sonnar. It corrected spherical and chromatic aberrations better, which made it one of the sharpest 50mm lenses of its time. Its performance at wide apertures set a new standard for Leica and justified the Summicron name.

Collapsible Design with Infinity Lock

The Elmar, Summar, and Summicron all share a collapsible barrel design, so the lens retracts 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. Field photographers who couldn’t afford misalignment mid-roll got a practical upgrade.

Front Element Made of Glass as Soft as Chalk

The early Summicron has a notorious flaw in its front element, which is 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, since 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 was simple, but it was revolutionary in 1925. It was based on a Cooke triplet, modified with an additional element, and it delivered sharp, high-contrast images with minimal distortion. Its compactness and reliability suited the nascent 35mm format. Even uncoated, it performed well in backlit conditions.

6-Blade Clickless Aperture Ring

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

Uncoated Optics with A36 Filter Fit

The original Elmar and Summar were uncoated, so they were prone to flare in strong backlight. Their contrast stayed high thanks 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, which improved 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 is more common, but it is rarely found in pristine condition because of 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.

eBay Listings

Leica 5cm 50mm f:2 DR Summicron lens only, US SELLER, "LQQK"

$550

[EXC+5] Leica Leitz Wetzlar Summitar 5cm F2 Collapsible L39

$300

Leica 5cm 50mm f2 Summitar Collapsible Lens LTM M39 #396

$337

Leica M 5cm 50mm f2 Summicron Lens Rigid Chrome #360

$622

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