Leica ELMARIT-M 21mm F/2.8 ASPH. [III]

Ultra-wide angle prime lens • Pro • Film era • Discontinued


ASPH. The lens incorporates aspherical elements.
III Third generation.

Production details

Production type:Mass production
Production status: Discontinued
Order No.:11135 - black anodized
11897 - silver chrome
Original name:LEICA ELMARIT-M 1:2.8/21 ASPH.
System:Leica M (1954)

Model history (3)

Leitz ELMARIT-M 21mm F/2.8 [I]M8 - 60.4mE49 1980 
Leitz / Leica ELMARIT-M 21mm F/2.8 [II]M8 - 60.7mE60 1987 
Leica ELMARIT-M 21mm F/2.8 ASPH. [III]M9 - 70.7mE55 1997 

Features highlight

Extreme AoV
8 blades


Optical design
Focal length:21mm
Maximum format:35mm full frame
Mount and Flange focal distance:Leica M [27.8mm]
Diagonal angle of view:91.7°
Lens construction:9 elements - 7 groups
1 ASPH, 2 AD, 3 HR
Diaphragm mechanism
Diaphragm type:Manual
Aperture control:Aperture ring
Number of blades:8 (eight)
Coupled to the rangefinder:Yes
Closest focusing distance:0.7m (coupled focusing)
Maximum magnification ratio:1:29 at the closest focusing distance
Focusing modes:Manual focus only
Manual focus control:Focusing tab
Physical characteristics
Maximum diameter x Length:⌀58×46mm
Filters:Screw-type 55mm
Lens hood:Slip-on 12592 (rectangular)
Lens caps:14269 (rear)
14379 (rear)

*) Source of data: Manufacturer's technical data.

35mm equivalent focal length and speed (on APS-H cameras)

In terms of FoV & DoF
Camera series [Crop factor] Focal length SpeedMax MR Dia. angle of view
Leica M8/M8.2 APS-H [1.33x] 27.9mm F/3.71:21.8 75.5°

Manufacturer description #1

With the introduction of the new ELMARIT-M f/2.8/21 mm ASPH., Leica Camera AG has added a new super-wide-angle lens of the highest optical performance to its range of lenses for the LEICA M6 and all older M models. The new lens replaces the ELMARIT-M f/2.8/ 21 mm, which has been manufactured in Canada since 1980.

In order to achieve a visible improvement of the image quality, the optical complexity was increased considerably in comparison with the lens’s predecessor: the new lens, which has been designed and will be manufactured in Germany, now comprises 9 elements in 7 components, including one element with an aspherical surface. Three of the elements are composed of high-refractive glass and two of glass with partial anomalous dispersion. Thanks to these improvements and a sophisticated optical design, a lens has been created which, although considerably smaller than its predecessor, features visibly enhanced optical performance.

Even at full aperture the lens is notable for its very good reproduction of contrast and detail in the centre of the image and across the entire image field. Comma and astigmatism are virtually non-existent up to an image height of 18 mm. This very good performance can be enhanced still further by stopping down slightly. Another remarkable feature of the lens is its perfectly flattened field and its low tendency towards flare under unfavourable shooting conditions, for example where the image contains light sources.

The level of vignetting inherent in an optical system is typically higher with a super-wide-angle lens than with lenses of standard or long focal lengths. This drop in light intensity towards the edges of the frame is particularly evident at low exposures, wide apertures and uniformly bright fields. The ELMARIT-M f/2.8/ 21 mm ASPH. shows no artificial vignetting whatsoever at apertures of 5.6 and over.

Despite the wider angle of view the level of barrel-shaped distortion is very low and is comparable with that of the ELMARIT-M f/2.8/ 24 mm ASPH., a lens which also exhibits excellent correction. It is barely discernible under normal photographic conditions.

Like the other new wide-angle lenses for the LEICA M system, i.e. the SUMMILUX-M f/1.4/35 mm ASPH., the ELMARIT-M f/2.8/ 24 mm ASPH. and the brand-new SUMMICRON-M f/2/35 mm ASPH., the aspherical glass surface is produced by high-precision “blank moulding“. A diamond-turned, accurately polished die manufactured from a type of ceramic is employed for this process. The die manufactured in this way corresponds perfectly in reverse to the surface of the lens to be manufactured. Parallel to tool manufacture, mathematical models were generated for definition of the surface tolerances, and the requisite optical measuring systems designed and constructed for continuous in-process monitoring of lens manufacture.

With its angle of view of 92°, this focal length is well suited to fast-moving reporting, landscape and architectural photography, and for crowd shots and other situations where space is limited. Even from a close distance, the entire scene can be taken in. Converging verticals, an unavoidable phenomenon for instance when high-rise buildings are shot from a close distance, can be used effectively and creatively, thereby exploiting the unusual perspective to attract the viewers attention.

Stopping down slightly is sufficient to achieve a depth of field which extends from the foreground into the far distance, enhancing the impression of depth in the picture. If, for example, there is not enough time for precise focusing, the photographer can still be sure of sharp results - an important plus for reporters.

Fine focusing and (on the LEICA M6 and LEICA M5) metering are performed through the integral bright-line viewfinder. The image is framed using the brilliant viewfinder, which is available as an accessory and can be attached to the camera hotshoe.

To avoid or reduce flare in the image for shots under unfavourable conditions, such as back-light exposures, the lens hood should always be left in place. The rectangular lens hood supplied with the lens is identical to that of the ELMARIT-M f/2.8/24 mm ASPH. For optimal protection against flare, however, its position on the lens has been modified slightly. Its carefully selected geometry ensures that the lens hood does not vignette the lens image or the range finder. At the same time, obstruction of the integral viewfinder is minimized by a cut-out in the upper right-hand corner of the lens hood.

A protective cap manufactured of a soft plastic material is supplied with the lens to protect the front element when the lens hood is in place. In addition, the photographer can use E 55 size Leica screw-in filters on the front of the lens if necessary. A high-quality nappa leather lens case protects the lens during transport.

The new lens provides further proof that sophisticated and complex optical design and state-of-the art production methods can be used to set new quality standards for super-wide-angle lenses. With the new ELMARIT-M f/2.8/21mm ASPH., Leica Camera AG has added yet another high-performance lens to the LEICA M system. Thanks to its compact design and excellent optical performance, this lens proudly takes its place in the new generation of super-wide-angle lenses.

Manufacturer description #2

Uniform sharpness and low distortion across the entire image area, even at full aperture, distinguish this lens. This is achieved with, among other factors, a lens element with an aspherical surface. Optimal for dramatic effects with monumental foreground, strongly receding background and a wide horizon. With this lens, focusing and exposure metering are performed by looking into the camera’s viewfinder, whereas the actual field coverage is checked by means of an accessory brilliant viewfinder.

Manufacturer description #3

This compact extreme wide-angle lens produces outstanding contrast and detail rendition at full aperture. The proverbial Leica image quality is preserved even in the close-up range. Distortion is minimal and negligible in photographic practice. At f/5.6 this lens is free of artificial vignetting. With all these qualities, it is ideally suited for dramatic effects with monumental foregrounds and strongly receding backgrounds with distant horizons. Because an extremely large depth-of-field is already achieved with a slightly stopped-down aperture, sharp dramatic pictures can be made during live reportage photography.

From the editor

Weight and dimensions are stated for the black version of the lens. Chrome version has the same dimensions but weighs 115g more (415g).

Typical application


Fast full-frame ultra-wide angle prime lens • Professional model

Professional model

  • Combination of focal length and speed meets professional demands

Genres or subjects of photography (5):

Landscapes • Cityscapes • Buildings • Interiors • Travel photography

Recommended slowest shutter speed when shooting static subjects handheld:

1/25th of a second

Alternatives in the Leica M system

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Lenses with similar focal length

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35mm full frame

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


Sorry, no additional information is available.


Replacement rear cover for Leica M-mount lenses.


Replacement rear cover, plastic, black finish, for Leica M-mount lenses.

Aspherical elements

Aspherical elements (ASPH, XA, XGM) are used in wide-angle lenses for correction of distortion and in large-aperture lenses for correction of spherical aberration, astigmatism and coma, thus ensuring excellent sharpness and contrast even at fully open aperture. The effect of the aspherical element is determined by its position within the optical formula: the more the aspherical element moves away from the aperture stop, the more it influences distortion; close to the aperture stop it can be particularly used to correct spherical aberration. Aspherical element can substitute one or several regular spherical elements to achieve similar or better optical results, which allows to develop more compact and lightweight lenses.

Use of aspherical elements has its downsides: it leads to non-uniform rendering of out-of-focus highlights. This effect usually appears as "onion-like" texture of concentric rings or "wooly-like" texture and is caused by very slight defects in the surface of aspherical element. It is difficult to predict such effect, but usually it occurs when the highlights are small enough and far enough out of focus.

Low dispersion elements

Low dispersion elements (ED, LD, SD, UD etc) minimize chromatic aberrations and ensure excellent sharpness and contrast even at fully open aperture. This type of glass exhibits low refractive index, low dispersion, and exceptional partial dispersion characteristics compared to standard optical glass. Two lenses made of low dispersion glass offer almost the same performance as one fluorite lens.

Low dispersion elements

Low dispersion elements (ED, LD, SD, UD etc) minimize chromatic aberrations and ensure excellent sharpness and contrast even at fully open aperture. This type of glass exhibits low refractive index, low dispersion, and exceptional partial dispersion characteristics compared to standard optical glass. Two lenses made of low dispersion glass offer almost the same performance as one fluorite lens.

Canon's Super UD, Nikon's Super ED, Pentax' Super ED, Sigma's FLD ("F" Low Dispersion), Sony' Super ED and Tamron's XLD glasses are the highest level low dispersion glasses available with extremely high light transmission. These optical glasses have a performance equal to fluorite glass.

High-refraction low-dispersion elements

High-refraction low-dispersion elements (HLD) minimize chromatic aberrations and ensure excellent sharpness and contrast even at fully open aperture.

High Index, High Dispersion elements

High Index, High Dispersion elements (HID) minimize chromatic aberrations and ensure excellent sharpness and contrast even at fully open aperture.

Anomalous partial dispersion elements

Anomalous partial dispersion elements (AD) minimize chromatic aberrations and ensure excellent sharpness and contrast even at fully open aperture.

Fluorite elements

Synthetic fluorite elements (FL) minimize chromatic aberrations and ensure excellent sharpness and contrast even at fully open aperture. Compared with optical glass, fluorite lenses have a considerably lower refraction index, low dispersion and extraordinary partial dispersion, and high transmission of infrared and ultraviolet light. They are also significantly lighter than optical glass.

According to Nikon, fluorite easily cracks and is sensitive to temperature changes that can adversely affect focusing by altering the lens' refractive index. To avoid this, Canon, as the manufacturer most widely using fluorite in its telephoto lenses, never uses fluorite in the front and rear lens elements, and the white coating is applied to the lens barrels to reflect light and prevent the lens from overheating.

Short-wavelength refractive elements

High and specialized-dispersion elements (SR) refract light with wavelengths shorter than that of blue to achieve highly precise chromatic aberration compensation. This technology also results in smaller and lighter lenses.

Blue Spectrum Refractive Optics

Organic Blue Spectrum Refractive Optics material (BR Optics) placed between convex and concave elements made from conventional optical glass provides more efficient correction of longitudinal chromatic aberrations in comparison with conventional technology.

Diffraction elements

Diffraction elements (DO, PF) cancel chromatic aberrations at various wavelengths. This technology results in smaller and lighter lenses in comparison with traditional designs with no compromise in image quality.

High refractive index elements

High refractive index elements (HR, HRI, XR etc) minimize field curvature and spherical aberration. High refractive index element can substitute one or several regular elements to achieve similar or better optical results, which allows to develop more compact and lightweight lenses.

Apodization element

Apodization element (APD) is in fact a radial gradient filter. It practically does not change the characteristics of light beam passing through its central part but absorbs the light at the periphery. It sort of softens the edges of the aperture making the transition from foreground to background zone very smooth and results in very attractive, natural looking and silky smooth bokeh.

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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/2.8 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.