Leitz Wetzlar SUMMARON 35mm F/3.5 with OVU

Wide-angle prime lens • Film era • Discontinued


Model history (4)

Leitz Wetzlar SUMMARON 35mm F/3.5 [LSM] (up to s/n 1,423,140)M6 - 41mA36 1950 
Leitz Wetzlar SUMMARON 35mm F/3.5M6 - 41mE39 1954 
Leitz Wetzlar SUMMARON 35mm F/3.5 [LSM] (from s/n 1,423,141)M6 - 41mE39 1956 
Leitz Wetzlar SUMMARON 35mm F/3.5 with OVUM6 - 40.65mE39 1956 

Features highlight

10 blades


Production details:
Production status: Discontinued
Order No.:SOONC-MW / SOMWO / 11107 - silver
Original name:Ernst Leitz GmbH Wetzlar Summaron f=3.5cm 1:3.5
System:Leica M (1954)
Optical design:
Focal length:35mm
Maximum format:35mm full frame
Mount and Flange focal distance:Leica M [27.8mm]
Diagonal angle of view:63.4°
Lens construction:6 elements in 4 groups
Diaphragm mechanism:
Diaphragm type:Manual
Aperture control:Aperture ring
Number of blades:10 (ten)
On Leica M8/M8.2 APS-H [1.33x] cameras:
35mm equivalent focal length:46.6mm (in terms of field of view)
35mm equivalent speed:F/4.7 (in terms of depth of field)
Diagonal angle of view:49.8°
Coupled to the rangefinder:Yes (from 0.65m)
Closest focusing distance:0.65m
Maximum magnification:<No data>
Focusing modes:Manual focus only
Manual focus control:Focusing lever
Physical characteristics:
Weight:<No data>
Maximum diameter x Length:<No data>
Filters:Screw-type 39mm
Lens hood:ITDOO / 12570
IROOA / 12571
Lens caps:ORQDO / 14031 (front)
IZQOO / 14051 (rear)
Source of data:
Scarce manufacturer's technical data + own research.

Manufacturer description #1

From the LEICA photography magazine (Fall 1956, Vol. 9, No. 3):

new 35mm wide-angle uses viewfinder of M-3!

bayonet-mounting lens is parallax-corrected to 26 inches

...the Leitz booth at Photokina displayed a second new lens - the 35mm Summaron f/3.5. This new wide-angle lens can be used with the regular M-3 rangefinder-viewfinder and needs no separate viewfinder. To bring the rangefinder-viewfinder image into line with the field of view of the 35mm wide-angle lens, there is an optical viewing unit which slides over the top part of the lens mount. It consists of two components mounted in a bracket. One of these provides correction to the viewfinder of the M-3, so that the field seen within the largest bright-line frame will correspond to the field of the 35mm lens. The other component, in front of the rangefinder opening, adjusts the secondary image, so that both images are the same size when you focus. A case for both lens and viewing unit is available.

Because of the use of this auxiliary optical unit, the coupling member of the M-3 rangefinder requires an adjustment to its movement from infinity to the closest range position. This is done by a special coupling member at the lens mount. Thus, you can operate the rangefinder properly only when the optical viewing unit is in front of the rangefinder and viewfinder. Used without the unit, the rangefinder would not register properly.

But, there is no chance for focusing mistakes. Without the adapter in position, the lens mount stays locked in infinity position! Mounting the optical viewing unit not only provides the necessary correction for the rangefinder-viewfinder but also automatically unlocks the lens for focusing.

The lens fits the bayonet mount on the Leica M-3 in the normal way. One improvement in the mounting method is that the red dot used for positioning is on a small "feelable" button, a feature especially suitable for working at night but which increases speed of lens mounting even in broad daylight. The new dual-range Summicron also has this feature.

Price of the new 35mm Summaron, complete with auxiliary optical unit is $135.00.

Manufacturer description #2

October 1, 1956:

Ernst Leitz, Wetzlar, has announced at the Photokina in Cologne, Germany, several new Leica items which will be of extreme interest to all Leica owners.

"RF" 35mm Summaron f/3.5 for the M-3

Another new lens is the "RF" 35mm Summaron f/3.5 wide-angle lens for the M-3 which functions in conjunction with the range- and viewfinder system of the M-3 Leica. This is a long awaited item, and unquestionably makes the already unique M-3 range- and viewfinder more versatile than before.

The "RF" Summaron comes with a detachable optical viewing unit which slips over the top of the lens mount, and corrects the range- and viewfinder for the 35mm field, which then appears within the heavy bright-line frame in the finder. The focusing range of this new lens is extended to as close as 26 inches and parallax compensation is automatic. This lens also features a linear diaphragm scale; all aperture markings being equidistant from each other. The new 35mm "RF" Summaron f/3.5 lens must be used with the optical viewing unit as it is locked in an infinity position when the viewer is not attached. Earlier Summaron 35mm f/3.5 lenses cannot be converted for use with the new viewing unit. The new lens is available in a bayonet mount for Leica M-3 cameras only (and replaces the current Summaron, Cat. #11105).

Manufacturer description #3

Leica ad, December, 1956:

NEW 35mm SUMMARON gives you wide-angle vision through the M-3's famed bright-line viewfinder!

Now you can have wide-angle photography with rangefinder focusing, full parallax correction, and all of the unique operational advantages found only in the automatic Leica M-3. The new Summaron f/3.5, equipped with its own optical viewing unit, completely converts the viewfinder-rangefinder system of the M-3 to the simplest wide-angle operation. The lens has a linear diaphragm scale and the optical viewing unit is detachable for convenient storage. With a focusing range from infinity to 26 inches, the 35mm Summaron spans a view 65 degrees wide.


  • All LEICA lenses having a focusing lever are automatically locked at the infinity position. This feature enables the camera to be used for infinity scenes and subjects without danger of the lens becoming accidentally out of focus due to unintentional movement. To release the lever for focusing on nearer planes press the knob at the end of the lever.

Alternatives in the Leica M system

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Wide-angle prime lens

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35mm full frame

43.27 24 36
  • Dimensions: 36 × 24mm
  • Aspect ratio: 3:2
  • Diagonal: 43.27mm
  • Area: 864mm2


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ITDOO / 12570 (1956)

For SUMMARON 3.5cm and SUMMICRON 5cm with E39 mounts. Velvet lining for reverse positioning. Narrow chrome band with above lens names engraved on black conical portion.

IROOA / 12571 (1959)

For 50mm and 35mm lenses with E39 mount. Double trigger fastening. Wide chrome band. Earliest examples were engraved "Summaron 3.5cm Summicron 5cm" but no codeword; later ones were engraved with either four or six focal length/aperture combinations and the codeword. Latest ones had the catalogue number and six focal length/aperture combinations.

12585 (1963)

For all 35mm and 50mm lenses with 42mm external mount diameter. All black. Engraved with either five or six focal length/aperture combinations and the catalogue number.

ORQDO / 14031

Spare lens cap, chromium plated, for lens diameter 42mm: SUPER-ANGULON 21mm f:4, SUMMARON 35mm f:3.5, SUMMARON 35mm f:2.8, SUMMICRON 35mm f:2, ELMAR 50mm f/3.5 [III], ELMAR 50mm f:2.8, SUMMICRON 50mm f:2, ELMARIT 90mm f:2.8, ELMAR 135mm f:4.

IZQOO / 14051

Replacement rear cover for Leica M-mount lenses.

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Image stabilizer

A technology used for reducing or even eliminating the effects of camera shake. Gyro sensors inside the lens detect camera shake and pass the data to a microcomputer. Then an image stabilization group of elements controlled by the microcomputer moves inside the lens and compensates camera shake in order to keep the image static on the imaging sensor or film.

The technology allows to increase the shutter speed by several stops and shoot handheld in such lighting conditions and at such focal lengths where without image stabilizer you have to use tripod, decrease the shutter speed and/or increase the ISO setting which can lead to blurry and noisy images.

Original name

Lens name as indicated on the lens barrel (usually on the front ring). With lenses from film era, may vary slightly from batch to batch.


Format refers to the shape and size of film or image sensor.

35mm is the common name of the 36x24mm film format or image sensor format. It has an aspect ratio of 3:2, and a diagonal measurement of approximately 43mm. The name originates with the total width of the 135 film which was the primary medium of the format prior to the invention of the full frame digital SLR. Historically the 35mm format was sometimes called small format to distinguish it from the medium and large formats.

APS-C is an image sensor format approximately equivalent in size to the film negatives of 25.1x16.7mm with an aspect ratio of 3:2.

Medium format is a film format or image sensor format larger than 36x24mm (35mm) but smaller than 4x5in (large format).

Angle of view

Angle of view describes the angular extent of a given scene that is imaged by a camera. It is used interchangeably with the more general term field of view.

As the focal length changes, the angle of view also changes. The shorter the focal length (eg 18mm), the wider the angle of view. Conversely, the longer the focal length (eg 55mm), the smaller the angle of view.

A camera's angle of view depends not only on the lens, but also on the sensor. Imaging sensors are sometimes smaller than 35mm film frame, and this causes the lens to have a narrower angle of view than with 35mm film, by a certain factor for each sensor (called the crop factor).

This website does not use the angles of view provided by lens manufacturers, but calculates them automatically by the following formula: 114.6 * arctan (21.622 / CF * FL),


CF – crop-factor of a sensor,
FL – focal length of a lens.


A lens mount is an interface — mechanical and often also electrical — between a camera body and a lens.

A lens mount may be a screw-threaded type, a bayonet-type, or a breech-lock type. Modern camera lens mounts are of the bayonet type, because the bayonet mechanism precisely aligns mechanical and electrical features between lens and body, unlike screw-threaded mounts.

Lens mounts of competing manufacturers (Canon, Nikon, Pentax, Sony etc.) are always incompatible. In addition to the mechanical and electrical interface variations, the flange focal distance can also be different.

The flange focal distance (FFD) is the distance from the mechanical rear end surface of the lens mount to the focal plane.

Lens construction

Lens construction – a specific arrangement of elements and groups that make up the optical design, including type and size of elements, type of used materials etc.

Element - an individual piece of glass which makes up one component of a photographic lens. Photographic lenses are nearly always built up of multiple such elements.

Group – a cemented together pieces of glass which form a single unit or an individual piece of glass. The advantage is that there is no glass-air surfaces between cemented together pieces of glass, which reduces reflections.

Focal length

The focal length is the factor that determines the size of the image reproduced on the focal plane, picture angle which covers the area of the subject to be photographed, depth of field, etc.


The largest opening or stop at which a lens can be used is referred to as the speed of the lens. The larger the maximum aperture is, the faster the lens is considered to be. Lenses that offer a large maximum aperture are commonly referred to as fast lenses, and lenses with smaller maximum aperture are regarded as slow.

In low-light situations, having a wider maximum aperture means that you can shoot at a faster shutter speed or work at a lower ISO, or both.

Closest focusing distance

The minimum distance from the focal plane (film or sensor) to the subject where the lens is still able to focus.

Closest working distance

The distance from the front edge of the lens to the subject at the maximum magnification.

Magnification ratio

Determines how large the subject will appear in the final image. For example, a magnification ratio of 1:1 means that the image of the subject formed on the film or sensor will be the same size as the subject in real life. For this reason, a 1:1 ratio is often called "life-size".

Manual diaphragm

The diaphragm must be stopped down manually by rotating the detent aperture ring.

Preset diaphragm

The lens has two rings, one is for pre-setting, while the other is for normal diaphragm adjustment. The first ring must be set at the desired aperture, the second ring then should be fully opened for focusing, and turned back for stop down to the pre-set value.

Semi-automatic diaphragm

The lens features spring mechanism in the diaphragm, triggered by the shutter release, which stops down the diaphragm to the pre-set value. The spring needs to be reset manually after each exposure to re-open diaphragm to its maximum value.

Automatic diaphragm

The camera automatically closes the diaphragm down during the shutter operation. On completion of the exposure, the diaphragm re-opens to its maximum value.

Fixed diaphragm

The aperture setting is fixed at F/3.5 on this lens, and cannot be adjusted.

Number of blades

As a general rule, the more blades that are used to create the aperture opening in the lens, the rounder the out-of-focus highlights will be.

Some lenses are designed with curved diaphragm blades, so the roundness of the aperture comes not from the number of blades, but from their shape. However, the fewer blades the diaphragm has, the more difficult it is to form a circle, regardless of rounded edges.

At maximum aperture, the opening will be circular regardless of the number of blades.


Excluding case or pouch, caps and other detachable accessories (lens hood, close-up adapter, tripod adapter etc.).

Maximum diameter x Length

Excluding case or pouch, caps and other detachable accessories (lens hood, close-up adapter, tripod adapter etc.).

For lenses with collapsible design, the length is indicated for the working (retracted) state.

Weather sealing

A rubber material which is inserted in between each externally exposed part (manual focus and zoom rings, buttons, switch panels etc.) to ensure it is properly sealed against dust and moisture.

Lenses that accept front mounted filters typically do not have gaskets behind the filter mount. It is recommended to use a filter for complete weather resistance when desired.

Fluorine coating

Helps keep lenses clean by reducing the possibility of dust and dirt adhering to the lens and by facilitating cleaning should the need arise. Applied to the outer surface of the front and/or rear lens elements over multi-coatings.


Lens filters are accessories that can protect lenses from dirt and damage, enhance colors, minimize glare and reflections, and add creative effects to images.

Lens hood

A lens hood or lens shade is a device used on the end of a lens to block the sun or other light source in order to prevent glare and lens flare. Flare occurs when stray light strikes the front element of a lens and then bounces around within the lens. This stray light often comes from very bright light sources, such as the sun, bright studio lights, or a bright white background.

The geometry of the lens hood can vary from a plain cylindrical or conical section to a more complex shape, sometimes called a petal, tulip, or flower hood. This allows the lens hood to block stray light with the higher portions of the lens hood, while allowing more light into the corners of the image through the lowered portions of the hood.

Lens hoods are more prominent in long focus lenses because they have a smaller viewing angle than that of wide-angle lenses. For wide angle lenses, the length of the hood cannot be as long as those for telephoto lenses, as a longer hood would enter the wider field of view of the lens.

Lens hoods are often designed to fit onto the matching lens facing either forward, for normal use, or backwards, so that the hood may be stored with the lens without occupying much additional space. In addition, lens hoods can offer some degree of physical protection for the lens due to the hood extending farther than the lens itself.


Teleconverters increase the effective focal length of lenses. They also usually maintain the closest focusing distance of lenses, thus increasing the magnification significantly. A lens combined with a teleconverter is normally smaller, lighter and cheaper than a "direct" telephoto lens of the same focal length and speed.

Teleconverters are a convenient way of enhancing telephoto capability, but it comes at a cost − reduced maximum aperture. Also, since teleconverters magnify every detail in the image, they logically also magnify residual aberrations of the lens.

Lens caps

Scratched lens surfaces can spoil the definition and contrast of even the finest lenses. Lens covers are the best and most inexpensive protection available against dust, moisture and abrasion. Safeguard lens elements - both front and rear - whenever the lens is not in use.