Leica IIIg

35mm MF film rangefinder camera


Production details:
Announced:February 1957
Order No.:GOOEF / 10250 - body without lens
GOOCE / 10252 - with ELMAR 50/3.5
GOOEL / 10255 - with ELMAR 50/2.8
GOOMI / 10261 - with SUMMICRON 50/2
GMOOA / 10265 - with SUMMARIT 50/1.5
System: Leica SM (1930)
Maximum format:35mm full frame
Film type:135 cartridge-loaded film
Mount and Flange focal distance:Leica screw mount [28.8mm]
Speeds:1 - 1/1000 + B
Exposure metering:None
Exposure modes:Manual
Rangefinder and Viewfinder:
Finder magnification:1.5x
Actual rangefinder base:39mm
Effective rangefinder base:58.5mm
Bright-line frames:50mm, 90mm
Parallax compensation:Yes
Physical characteristics:
Dimensions:<No data>
Body cap:14055
LOPEN / 35355

Manufacturer description #1

From the LEICA photography magazine (1957, No. 1):

IIIg... newest of the classic Leicas

redesigned viewfinder heads list of improvements

Each new Leica model, with the exception of the Leica M-3, has been an evolutionary step from the original and, by now, classic design of Oskar Barnack. Only when Leitz designers have been sure that changes would contribute to the final goal of better pictures, has the camera been altered. With this in mind, the announcement of the new Leica IIIg (replacing the IIIf) is an exciting event.

new viewfinder

The biggest advance in the IIIg is its new viewfinder. The large (.7x lifesize) image has superimposed on it a bright-line frame outlining the field of 50mm lenses. Within the 50mm field, four bright triangles show the corners of the field of 90mm lenses. Incorporated in the new viewfinder is automatic parallax correction through the entire focusing range of the lenses for both 50mm and 90mm frame indicators.

Another feature of the new viewfinder is its freedom from "eye parallax." That is, if you do not look directly through the center of the finder when shooting fast, for example, you will still frame accurately.

As in the IIIf, the rangefinder of the new IIIg is separate from the viewfinder, but its eyepiece is located right next to the viewfinder eyepiece. The rangefinder image is magnified 1.5x for critical accuracy in focusing. The rangefinder optics can be focused on near or distant objects as well as be accommodated to your own individual eyesight.

automatic flash synchronization

An outstanding addition to the IIIg is its automatic flash synchronization. Like the M-3, it needs no special synchro-dial setting to change the "synch" timing when you change shutter speeds. When you reset the shutter speed the flash contact points are reset automatically for proper synchronization.

shutter speeds

Shutter speeds on the IIIg are designed to correlate exactly with diaphragm settings; each step, up or down, gives one-half or twice the exposure, as does each step on the aperture scale.

The fast-speed dial on top of the camera gives speeds of 1/1000, 1/500, 1/250, 1/125, 1/60, 1/30 second and "Bulb." The slow speed dial, on the front of the camera, gives 1/30, 1/15, 1/8, 1/4, 1/2, 1 second and "Time."


The new IIIg has the same standard threaded lens flange as the IIIf and previous Leicas with interchangeable lenses. The same lenses now available for such Leicas will be supplied for the new camera. A new screw-mounting 50mm Elmar f/2.8 lens will be available soon in limited quantities.

electronic flash

On the fast-speed dial there are two extra shutter settings marked in red and black for use with zero-delay electronic flash units or five-millisecond delay bulbs such as the SF and M2. These markings are located next to the 1/60th and 1/30th settings. Both may be used for electronic flash; five-millisecond delay bulbs work only at red arrow setting next to 1/ 30th.

film exposure index reminder

The film exposure index reminder has been moved from the winding knob to the back of the IIIg housing. It is calibrated for both ASA and DIN ratings, and can be set as high as 1000 ASA. The winding knob and self-timer, rewind knob and exposure counter are the same on the IIIg as on the IIIf.

In overall looks, the IIIg is quite similar to the IIIf. However, the top section of the body is somewhat higher in the IIIg. The Leicavit rapid winder fits the IIIg without alteration. Close-up devices like the SOOKY and Focoslide will be available for the IIIg later in the year.

There will not be a model IIg to replace the discontinued IIf camera, but production of the If will continue. No conversion of previous screw-threaded Leica models to a IIIg is possible.

Price of the IIIg with collapsible 50mm Summicron f/2 lens is $342.00. With a 50mm Elmar f/3.5 lens, the price is $244.50.

Manufacturer description #2

February 15, 1957:

We are pleased to announce a number of important new products - including a new Leica IIIg Camera, a new f/2.8 50mm Elmar Lens, and various other items.


Since the introduction of the Leica M 3, the most advanced of all Leica models, Leitz engineers have been at work to improve the IIIf, the classic Oskar Barnack Leica design. This new camera is now here and the improvements are so important that it has been given a new designation: "IIIg". The more important improvements are outlined below.

a) Improved Viewfinder

The viewfinder is of the bright-line type, similar to the viewfinder of the M 3, giving a larger image than the IIIf finder and offering freedom from eye parallax. The corners of the 90mm frame are also indicated by bright triangles, which eliminate the necessity of an auxiliary viewfinder for the 90mm lens. While the eyepieces of view- and rangefinder are still separated, it is easier to shift from one to the other than it was with previous models.

b) Automatic Parallax Correction

The bright-line frame of the viewfinder is connected with the focusing mechanism and moves so that there is always complete correction for parallax within the entire focusing range of the lens.

c) Automatic Flash Synchronization Adjustment

The synchro dial has been eliminated. Changing shutter speeds automatically resets the built-in synchronizer for flash bulb photography. Special shutter speed settings are provided for electronic flash.

d) Geometric Shutter Speeds are arranged to follow a logical progression in which each speed gives twice as much exposure as the next faster shutter speed: 1/1000, 1/500, 1/250, 1/125, 1/60, 1/30, 1/15, 1/8, 1/4, 1/2, 1.

e) The Method of Changing Lenses is the same as on the IIIf. The IIIg accepts all screw-in type Leica lenses.

There are numerous other refinements in the IIIg such as the film indicator on the back similar to that on the M 3 and other items which you will recognize when you see and handle this new camera.

Manufacturer description #3

The Leica lIIg has many features which give it outstanding performance. Its shutter speeds run from 1 second to 1/1000th second, "Time" and "Bulb". They are in geometric sequence - each gives half or double the exposure time of the one next to it on the dial. This correlates with the aperture stops, since each stop admits half or twice the light of the stop next to it.

The bright-line frame viewfinder of the lIIg shows the field of 50mm lenses. Within the 50mm field, four bright "corners" mark the field of 90mm lenses. Parallax compensation for both fields is automatic throughout the entire normal focusing range of lenses. The built-in range-finder couples automatically to the lenses and magnifies the image 1.5X for extreme accuracy in focusing. Its eyepiece is alongside the viewfinder eyepiece in a twin mount.

As in the M 3 and M 2, flash synchronization for both electronic units and flash bulbs is automatic in the lIIg. There are no dial settings to make. When you set the shutter speed, synchronization is set automatically.

All screw-mounting lenses available for previous Leica models will fit the IIlg; many accessories, including the famous Leicavit Rapid Winder are available for it. However, earlier models of the Leica cannot be converted into the IIlg.

Manufacturer description #4

Body with carrying strap eyelets, hard rubber covering bonded to camera housing, and chromium-plated metal parts; built-in bright-line frame finder for both 50 mm and 90 mm lenses, with automatic parallax compensation for both focal lengths; automatic flash synchronization for conventional and electronic flash units (X and M); lens-coupled, coincident-type rangefinder with 1.5 x magnification, focal plane shutter with speeds from 1 second to 1/1000 second, T and B; built-in self-timer; simultaneous shutter wind, film advance and exposure counter; accessory clip; screw-threaded lens mount.

Manufacturer description #5

The LEICA III g differs from the LEICA III f in the following technical features:

  1. Large bright-line viewfinder with automatic parallax compensation.
  2. Shutter speeds graduated in geometric progression.
  3. Fully automatic synchronization (without contact numbers).
  4. Film indicator in the back of the camera body.

Serial No. from 825001.

Manufacturer description #6

FROM IIIf to IIIg...


Here is the latest design of the camera that is the core of the classic LEICA system. The IIIg improves and perpetuates the precision camera long famous for the greatest variety and versatility in 35mm photography.

improved viewfinder vision: larger, clearer image, with brightline frame for the 50mm lens field and luminous corners indicating the 90mm lens field - both with automatic parallax correction through the entire focusing range.

automatic synchronization, for standard or electronic flash, adjusts when shutter speeds are set.

improved rangefinder visibility is an outstanding feature of the IIIg rangefinder optical system of 1.5x magnification. This system adjusts for critical focusing and individual vision with greater ease than before.

other famous LEICA features: Full-range focal-plane shutter, 1 sec. to 1/1000 sec., T and B, calibrated to correlate with f-stops. Screw-mount interchangeability for over 12 different lenses. Compactness, light weight, easy operation. Plus the "little" things that count: film reminder dial, built-in self timer, accessory clip, "soft-action" release button. Leicavit, rapid winder for sequence photography, replaces the baseplate, is available as an accessory.

From the editor

The last and the best of Leica's screw mount cameras. Also one of the most sophisticated.

About 41,583 units were made from 1957 to 1961, and in 1970.

Similar cameras (63)

35mm full frame • Manual focus • Film • Rangefinder • Leica screw mount mount

Model Shutter Metering Modes Year
Canon 7 M, 1/1000 Window M 1961
Canon 7s M, 1/1000 Window M 1965
Canon II-A M, 1/1000 -- M 1952
Canon II-AF M, 1/500 -- M 1953
Canon II-AX M, 1/500 -- M 1953
Canon II-B M, 1/500 -- M 1949
Canon II-C M, 1/500 -- M 1950
Canon II-D M, 1/500 -- M 1952
Canon II-D1 M, 1/500 -- M 1952
Canon II-D2 M, 1/500 -- M 1955
Canon II-F M, 1/500 -- M 1953
Canon II-F2 M, 1/500 -- M 1955
Canon II-S M, 1/500 -- M 1954
Canon II-S2 M, 1/500 -- M 1955
Canon III M, 1/1000 -- M 1951
Canon III-A M, 1/1000 -- M 1951
Canon IV M, 1/1000 -- M 1951
Canon IV-F (IV-S) M, 1/1000 -- M 1952
Canon IV-SB M, 1/1000 -- M 1952
Canon IV-SB2 M, 1/500 -- M 1954
Canon L1 M, 1/1000 -- M 1957
Canon L2 M, 1/500 -- M 1957
Canon L3 M, 1/500 -- M 1957
Canon P M, 1/1000 -- M 1959
Canon VI-L M, 1/1000 -- M 1958
Canon VI-T M, 1/1000 -- M 1958
Canon VL M, 1/1000 -- M 1958
Canon VL2 M, 1/500 -- M 1958
Canon VT M, 1/1000 -- M 1956
Canon VT de luxe M, 1/1000 -- M 1957
Cosina Voigtlander BESSA-R M, 1/2000 TTL • WA M 2000
Drug M, 1/1000 -- M 1960
FED M, 1/500 -- M 1934
FED-2 M, 1/500 -- M 1955
FED-2L M, 1/500 -- M 1969
FED-3 M, 1/500 -- M 1961
FED-4[K] M, 1/500 Window M 1964
FED-5 M, 1/500 Window M 1977
FED-5S M, 1/500 Window M 1977
FED-5V M, 1/500 -- M 1975
Leningrad M, 1/1000 -- M 1956
Minolta-35 Model A M, 1/500 -- M 1947
Minolta-35 Model B M, 1/500 -- M 1947
Minolta-35 Model C M, 1/500 -- M 1948
Minolta-35 Model D M, 1/500 -- M 1949
Minolta-35 Model E M, 1/500 -- M 1951
Minolta-35 Model F M, 1/500 -- M 1952
Minolta-35 Model II M, 1/500 -- M 1953
Minolta-35 Model IIB M, 1/500 -- M 1958
Mir M, 1/500 -- M 1959
Yashica YE M, 1/500 -- M 1959
Yashica YF M, 1/1000 -- M 1959
Zorki M, 1/500 -- M 1948
Zorki-2 M, 1/500 -- M 1954
Zorki-2S M, 1/500 -- M 1955
Zorki-3 M, 1/1000 -- M 1951
Zorki-3M M, 1/1000 -- M 1954
Zorki-3S M, 1/1000 -- M 1955
Zorki-4 M, 1/1000 -- M 1956
Zorki-4K M, 1/1000 -- M 1972
Zorki-5 M, 1/500 -- M 1958
Zorki-6 M, 1/500 -- M 1959
Zorki-S M, 1/500 -- M 1955
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Chromatic aberration

There are two kinds of chromatic aberration: longitudinal and lateral. Longitudinal chromatic aberration is a variation in location of the image plane with changes in wave lengths. It produces the image point surrounded by different colors which result in a blurred image in black-and-white pictures. Lateral chromatic aberration is a variation in image size or magnification with wave length. This aberration does not appear at axial image points but toward the surrounding area, proportional to the distance from the center of the image field. Stopping down the lens has only a limited effect on these aberrations.

Spherical aberration

Spherical aberration is caused because the lens is round and the film or image sensor is flat. Light entering the edge of the lens is more severely refracted than light entering the center of the lens. This results in a blurred image, and also causes flare (non-image forming internal reflections). Stopping down the lens minimizes spherical aberration and flare, but introduces diffraction.


Astigmatism in a lens causes a point in the subject to be reproduced as a line in the image. The effect becomes worse towards the corner of the image. Stopping down the lens has very little effect.


Coma in a lens causes a circular shape in the subject to be reproduced as an oval shape in the image. Stopping down the lens has almost no effect.

Curvature of field

Curvature of field is the inability of a lens to produce a flat image of a flat subject. The image is formed instead on a curved surface. If the center of the image is in focus, the edges are out of focus and vice versa. Stopping down the lens has a limited effect.


Distortion is the inability of a lens to capture lines as straight across the entire image area. Barrel distortion causes straight lines at the edges of the frame to bow toward the center of the image, producing a barrel shape. Pincushion distortion causes straight lines at the edges of the frame to curve in toward the lens axis. Distortion, whether barrel or pincushion type, is caused by differences in magnification; stopping down the lens has no effect at all.

The term "distortion" is also sometimes used instead of the term "aberration". In this case, other types of optical aberrations may also be meant, not necessarily geometric distortion.


Classically, light is thought of as always traveling in straight lines, but in reality, light waves tend to bend around nearby barriers, spreading out in the process. This phenomenon is known as diffraction and occurs when a light wave passes by a corner or through an opening. Diffraction plays a paramount role in limiting the resolving power of any lens.


Doublet is a lens design comprised of two elements grouped together. Sometimes the two elements are cemented together, and other times they are separated by an air gap. Examples of this type of lens include achromatic close-up lenses.

Dynamic range

Dynamic range is the maximum range of tones, from darkest shadows to brightest highlights, that can be produced by a device or perceived in an image. Also called tonal range.

Resolving power

Resolving power is the ability of a lens, photographic emulsion or imaging sensor to distinguish fine detail. Resolving power is expressed in terms of lines per millimeter that are distinctly recorded in the final image.


Vignetting is the darkening of the corners of an image relative to the center of the image. There are three types of vignetting: optical, mechanical, and natural vignetting.

Optical vignetting is caused by the physical dimensions of a multi-element lens. Rear elements are shaded by elements in front of them, which reduces the effective lens opening for off-axis incident light. The result is a gradual decrease of the light intensity towards the image periphery. Optical vignetting is sensitive to the aperture and can be completely cured by stopping down the lens. Two or three stops are usually sufficient.

Mechanical vignetting occurs when light beams are partially blocked by external objects such as thick or stacked filters, secondary lenses, and improper lens hoods.

Natural vignetting (also known as natural illumination falloff) is not due to the blocking of light rays. The falloff is approximated by the "cosine fourth" law of illumination falloff. Wide-angle rangefinder designs are particularly prone to natural vignetting. Stopping down the lens cannot cure it.


Bright shapes or lack of contrast caused when light is scattered by the surface of the lens or reflected off the interior surfaces of the lens barrel. This is most often seen when the lens is pointed toward the sun or another bright light source. Flare can be minimized by using anti-reflection coatings, light baffles, or a lens hood.


Glowing patches of light that appear in a photograph due to lens flare.

Retrofocus design

Design with negative lens group(s) positioned in front of the diaphragm and positive lens group(s) positioned at the rear of the diaphragm. This provides a short focal length with a long back focus or lens-to-film distance, allowing for movement of the reflex mirror in SLR cameras. Sometimes called an inverted telephoto lens.


A photographic lens completely corrected for the three main optical aberrations: spherical aberration, coma, and astigmatism.

By the mid-20th century, the vast majority of lenses were close to being anastigmatic, so most manufacturers stopped including this characteristic in lens names and/or descriptions and focused on advertising other features (anti-reflection coating, for example).

Rectilinear design

Design that does not introduce significant distortion, especially ultra-wide angle lenses that preserve straight lines and do not curve them (unlike a fisheye lens, for instance).

Focus shift

A change in the position of the plane of optimal focus, generally due to a change in focal length when using a zoom lens, and in some lenses, with a change in aperture.


The amount of light that passes through a lens without being either absorbed by the glass or being reflected by glass/air surfaces.

Modulation Transfer Function (MTF)

When optical designers attempt to compare the performance of optical systems, a commonly used measure is the modulation transfer function (MTF).

The components of MTF are:

The MTF of a lens is a measurement of its ability to transfer contrast at a particular resolution from the object to the image. In other words, MTF is a way to incorporate resolution and contrast into a single specification.

Knowing the MTF curves of each photographic lens and camera sensor within a system allows a designer to make the appropriate selection when optimizing for a particular resolution.

Veiling glare

Lens flare that causes loss of contrast over part or all of the image.

Anti-reflection coating

When light enters or exits an uncoated lens approximately 5% of the light is reflected back at each lens-air boundary due to the difference in refractive index. This reflected light causes flare and ghosting, which results in deterioration of image quality. To counter this, a vapor-deposited coating that reduces light reflection is applied to the lens surface. Early coatings consisted of a single thin film with the correct refractive index differences to cancel out reflections. Multi-layer coatings, introduced in the early 1970s, are made up of several such films.

Benefits of anti-reflection coating:

Circular fisheye

Produces a 180° angle of view in all directions (horizontal, vertical and diagonal).

The image circle of the lens is inscribed in the image frame.

Diagonal (full-frame) fisheye

Covers the entire image frame. For this reason diagonal fisheye lenses are often called full-frame fisheyes.

Extension ring

Extension rings can be used singly or in combination to vary the reproduction ratio of lenses. They are mounted between the camera body and the lens. As a rule, the effect becomes stronger the shorter the focal length of the lens in use, and the longer the focal length of the extension ring.

View camera

A large-format camera with a ground-glass viewfinder at the image plane for viewing and focusing. The photographer must stick his head under a cloth hood in order to see the image projected on the ground glass. Because of their 4x5-inch (or larger) negatives, these cameras can produce extremely high-quality results. View cameras also usually support movements.

135 cartridge-loaded film

43.27 24 36
  • Introduced: 1934
  • Frame size: 36 × 24mm
  • Aspect ratio: 3:2
  • Diagonal: 43.27mm
  • Area: 864mm2
  • Double perforated
  • 8 perforations per frame

120 roll film

71.22 44 56
  • Introduced: 1901
  • Frame size: 56 × 44mm
  • Aspect ratio: 11:14
  • Diagonal: 71.22mm
  • Area: 2464mm2
  • Unperforated

120 roll film

79.2 56 56
  • Introduced: 1901
  • Frame size: 56 × 56mm
  • Aspect ratio: 1:1
  • Diagonal: 79.2mm
  • Area: 3136mm2
  • Unperforated

120 roll film

89.64 56 70
  • Introduced: 1901
  • Frame size: 70 × 56mm
  • Aspect ratio: 5:4
  • Diagonal: 89.64mm
  • Area: 3920mm2
  • Unperforated

220 roll film

71.22 44 56
  • Introduced: 1965
  • Frame size: 56 × 44mm
  • Aspect ratio: 11:14
  • Diagonal: 71.22mm
  • Area: 2464mm2
  • Unperforated
  • Double the length of 120 roll film

220 roll film

79.2 56 56
  • Introduced: 1965
  • Frame size: 56 × 56mm
  • Aspect ratio: 1:1
  • Diagonal: 79.2mm
  • Area: 3136mm2
  • Unperforated
  • Double the length of 120 roll film

220 roll film

89.64 56 70
  • Introduced: 1965
  • Frame size: 70 × 56mm
  • Aspect ratio: 5:4
  • Diagonal: 89.64mm
  • Area: 3920mm2
  • Unperforated
  • Double the length of 120 roll film

Shutter speed ring with "F" setting

The "F" setting disengages the leaf shutter and is set when using only the focal plane shutter in the camera body.

Catch for disengaging cross-coupling

The shutter and diaphragm settings are cross-coupled so that the diaphragm opens to a corresponding degree when faster shutter speeds are selected. The cross-coupling can be disengaged at the press of a catch.

Cross-coupling button

With the cross-coupling button depressed speed/aperture combinations can be altered without changing the Exposure Value setting.

M & X sync

The shutter is fully synchronized for M- and X-settings so that you can work with flash at all shutter speeds.

In M-sync, the shutter closes the flash-firing circuit slightly before it is fully open to catch the flash at maximum intensity. The M-setting is used for Class M flash bulbs.

In X-sync, the flash takes place when the shutter is fully opened. The X-setting is used for electronic flash.

X sync

The shutter is fully synchronized for X-setting so that you can work with flash at all shutter speeds.

In X-sync, the flash takes place when the shutter is fully opened. The X-setting is used for electronic flash.

LOPEN / 35355

Lens opening cover of metal for LEICA screw-mount cameras.


Protection cap, for camera body with screw thread, chromium plated.


Protection cap, for camera body with screw thread, black finish.

Unable to follow the link

You are already on the page dedicated to this lens.

Cannot perform comparison

Cannot compare the lens to itself.

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. Magnification is expressed as a ratio. 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 focus override in autofocus mode

Allows to perform final focusing manually after the camera has locked the focus automatically. Note that you don't have to switch camera and/or lens to manual focus mode.

Manual focus override in autofocus mode

Allows to perform final focusing manually after the camera has locked the focus automatically. Note that you don't have to switch camera and/or lens to manual focus mode.

Electronic manual focus override is performed in the following way: half-press the shutter button, wait until the camera has finished the autofocusing and then focus manually without releasing the shutter button using the focusing ring.

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/ 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.