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Leica R4 [MOT Electronic]

35mm MF film SLR camera

Specification

Production details:
Announced:1980
Order No.:10041 - silver chrome
10043 - black chrome
System:● Leica R (1964)
Format:
Maximum format:35mm full frame
Film type:135 cartridge-loaded film
Mount and Flange focal distance:Leica R [47mm]
Shutter:
Type:Focal-plane
Model:Electronically controlled
Speeds:1 - 1/1000 + B
Exposure:
Exposure metering:Through-the-lens (TTL), open-aperture
Exposure modes:Programmed Auto
Aperture-priority Auto
Shutter-priority Auto
Manual
Physical characteristics:
Weight:630g
Dimensions:138.5x88.1x60mm
Accessories:
Body cap:14103

Manufacturer description #1

Single lens reflex camera with electronically-controlled metal-blade focal-plane shutter. Two exposure measuring methods (Leitz selective measurement and Leitz largefield integral measurement) coupled with the following operating modes: aperture priority, shutter speed priority, automatic mode and manual setting.

In addition, automatic switch-over to "X" with system-compatible electronic flash units. Electronically-controlled shutter speeds from 1/1000 to about 8 sec. X = 1/100 sec. for electronic-flash synchronisation. Interchangeable focusing screens.

Detachable camera back. Automatic frame counter and film transport check. Film cartridge window. Rapid film change. Rapid lens bayonet changer. Was initially supplied under the name "LEICA R4-MOT ELECTRONIC".

Serial No. from 1533351.

Manufacturer description #2

The LEICA R4-MOT is the 4th generation reflex LEICA. It is both the most universal camera as well as the simplest to operate ever designed and built by Leitz. Its electronics serve primarily to simplify the operation and to increase photo-readiness.

For the photographer this means: Perfect problem-free pictures. The time tested method of auto-exposure with integrated or selective spot-measurement plays an important role. The basis for optimal accommodation to prevailing tasks required in simple, practical photography is achieved by a aperture-programmed- and flash-automatic exposure system.

The LEICA R4-MOT is compact and functional and it fits your hand like a glove. Operating convenience, reliability, excellent optical quality and the worldwide service network make it equally desirable for the professional as well as the serious amateur.

Manufacturer description #3

The LEICA R4 is the 4th-generation S.L.R. camera. Full use has been made of electronics to simplify its operation and increase its instant readiness. To the photographer this means perfect pictures without having to solve any technical problems. The well proven automatic exposure measuring methods for both integral and selective measurement, unique in LEICA-R models, give them a distinct advantage in achieving perfect exposures. Coupled with the instant choice of automatic shutter priority, aperture-priority, program or flash modes, the basis for optimum versatility and application to the situation is formed for a simple, practical approach to perfect photography. The design and configuration of the LEICA R4 is elegant, compact and functional; and the camera fits comfortably in the hand. Outstanding operation convenience, reliability, optical performance and its world-wide service organization make it the most attractive choice for the professional photographer, the sophisticated amateur or quality-conscious novice. The camera feature of greatest importance to the LEICA user is the end result. All of this is due to almost 150 years of Leitz experience in the manufacture of precision instruments in metrology and high-quality researcn microscopes. No other manufacturer can bring more experience in precision machining, high quality optical systems, and technical perfection to a camera than Leitz. This is why the LEICA R4 is able to meet the most stringent demands.

Like the LEICA R3-MOT, it is manufactured in the Leitz factory in Portugal using the well-proven Leitz production specifications. Conveyor belt production is ruled out, as is any compromise in favor of higher production and assembly.

Lenses of focal lengths from 15mm to 800mm are available for the LEICA R4 system. In addition to the well established facilities in Wetzlar, Germany, many of the world famous LEICA lenses are manufactured in the Leitz factory in Canada.

The outstanding advantages of the LEICA R4

  • The flawless Leitz black chromium finish assures a like-new appearance after years of constant use.
  • Balanced proportions along with greatest operating convenience make the LEICA R4 a pleasure to handle. It is conducive to effortless, quick and reliable photography under any condition.
  • The choice of integral or seIective exposure measuring methods combined with its multiple modes, automatically meet any photographic requirement - simply. Electronics insure easy, reliable, and accurate exposure.
  • The metal multi-blade focal-plane shutter of the LEICA R4 makes winding smooth and easy, and the electro-magnetic shutter release permits vibration-free, quiet performance.
  • Interchangeable focusing screens permit the LEICA R4 to compose and be focused to the highest degree of accuracy possible. The primary semi-transparent mirror is coated with seventeen deposition technique dichroic coatings which reflect 70% of the light transmitted by the lens; resulting in an extremely brilliant viewfinder image.
  • Motor Winder and Motor Drive - greatly extend the range of dynamic photography. The LEICA R4 is the nucleus of a universal system. Lenses from 15mm to 800mm focal length cover every photographic need. All current lenses of the LEICA R3/R3-MOT can be used on the LEICA R4 without modification.
  • The large reliable LEICA R - bayonet lens mount permits quick lens change. Even with prolonged and frequent use, the precise and secure seating dimensions are retained after many years of constant use.

Integrating and selective - a guarantee for successful exposures

A simple automatic system cannot deal successfully with every lighting condition; special conditions require special measuring methods. Therefore, the LEICA R4 camera has two exposure measuring methods:

  • A center weighted large field integrating method for all scenes with normal lighting conditions.
  • And, as something extra, the Leitz selective measuring method, which allows measuring a specific, important portion of the scene, and is thus able to deal with even difficult lighting conditions.

In many cases the integrating method is the correct and dependable one. True in all cases if there are no extreme light- and color contrasts, no heavy shadows and when the bright and dark portions in the image plane are about even. The exposure meter now registers the result of the entire image area.

Since usually the important detail is in the center, the measurement is center-weighted.

Unusual photos are generally made under uncommon and difficult lighting conditions - against the light scenes, side light, spotlighted scenes - etc. This is the strong point of the Leitz selective measurement method. Scenes before a bright or very dark background, a portrait against the light, the view through an arched gate, open light sources - these are no problems for the LEICA R4. The measurement area corresponds to the central circle in the viewfinder. Use this circle to aim for the important image portion and release the shutter. The exposure time will consider in its exposure determination only that portion which lies within the circle, regardless of what occurs within the rest of the viewfinder area.

The selective measurement method, per se, is an excellent feature, but this is not all. Frequently, the selectively measured detail does not really belong in the middle. It is for this reason that the measured value can be stored for 30 seconds by depressing the shutter release button until the mode symbol at the lower left is extinguished. Thereafter the desired picture frame may be chosen in good time and the shutter released under the predetermined exposure value.

Measuring selectively, value storage, determination of the desired picture area and shutter release are done so quickly and easily with the LEICA R4 that the photographer can carry out these functions after a short time almost unconsciously. Obviously, this is the best prerequisite for optimum picture composition and perfect exposure without technical problems.

The programs of the LEICA R4

The programs of the LEICA R4 are designed to master any photographic situation. Their operation is so simple and reliable that the photographer can fully concentrate on the subject. The camera automatically takes care of all the technical aspects.

However, the shutter speeds and aperture can also be set manually in the event of very unusual photographic circumstances or applications. Setting the specific program is extremely simple. The program selector is changed without having to take the camera away from the eye. The symbol of the selected program appears in the viewfinder frame. All other data of importance is also visible in the viewfinder. The LEICA R4 permits instant accommodation for any photographic situation. These programs have been developed as the result of years of photographic experience.

The viewfinder - your control center for perfect pictorial composition

At a single glance the viewfinder of the LEICA R4 shows all the information necessary for the composition and accurate focusing of the subject. The viewfinder image is clear and brilliant even under poor lighting conditions.

Interchangeable focusing screens permit rapid and precise focusing for just about every photographic application.

This is the most important criterion for the full utilization of the outstanding optical performance of a LEICA-R lens.

Technical details

Type of camera: Electronically controlled 35mm s.l.r. camera with alternative measuring methods through the lens: LEITZ selective measurement or LEITZ largefield integrating measurement, combined with multiple automatic modes.

Body: All-metal body with detachable back, length 138.5mm, height 88.1 mm, depth 60mm, weight 630g. A1/4 (1/4in) tripod bush. LEICA R rapid changing bayonet.

Viewfinder: Built-in pentaprism, interchangeable focusing screens, LED display in the viewfinder, viewfinder magnification about 0.85x with 50mm lens, the viewfinder image corresponds to 92% of the film area (= picture area of a mounted slide).

Shutter: Vertically-acting metal-blade focal-plane shutter with electronically and continuously adjusted speeds from 1/1000 to about 8sec with automatic mode. Manual settings: 1/1000, 1/500, 1/250, 1/125, 1/60, 1/30, 1/15, 1/8, 1/4, 1/2, 1 sec.

Mechanically controlled speeds: X (1/100 sec), 100 (1/100sec), B. 100 and B function also without batteries. Electronic flash synchronisation 1/100 sec. Automatic switch-over when system-compatible flash units are used.

Current supply: Two 1.55v silver oxide button cells for the exposure meter and the shutter.

Special technical details of the LEICA R4

Electronic self timer: The delay time of the self-timer is about 8 sec. A blinking light indicates that it is operating. This changes to a steady light signal about 2 seconds before the shutter is released.

Double and multiple exposures: When the rewind button is depressed the film transport is disengaged. The shutter can now be wound by means of the rapid winding lever without the film transporting. At the end of the travel of the lever the rewind button automatically resets. If more than two exposures are to be made on a single frame, the rewind button must be pressed again before the shutter is wound.

Databack DB LEICA R4: The databack enables the user to record data directly on the film. Negatives or transparencies may be given letter or numerical codes; for instance, when one wishes to serialize a group of photographs. The data may also be an important factor to reconstruct the specific phases or events that were in effect at the time the pictures were taken. The opportunities are manifold. Whether one takes family photos or one wishes to photograph various stages during building of a home, or for experimental photography in the laboratory, the databack allows the identification of the photograph with security and convenience. Databack DB R4 can be inserted in place of the back of the LEICA R4 and connected by means of a cable to the flash contact of the camera.

Depth-of-field preview lever: For the determination of the depth-of-field at a preselected aperture a conveniently arranged depth-of-field preview lever is depressed. This closes the lens aperture to the preselected value.

Film and battery test: A window in the camera back shows clearly if and with what film the camera is loaded. For testing the battery condition, simply depress the test button. If the red control lamp lights up the batteries are ok.

Flatness of the film: The outstanding flatness of the film in the LEICA R4 must also be emphasized: It is absolutely essential for the optimum utilization of lens performance and that excellent sharpness is maintained over the entire picture area.

The motorized LEICA R4 - for action, sequence, and remote release photos

In many situations, constant readiness for action and follow-up photos are essential for successful dynamic pictures. The Motor-Winder and the Motor-Drive for the LEICA R4 expand the possibilities of dynamic photography and of fully automatic image recording in many ways. With motor wind and film transport the LEICA R4 is better suited for quick single and sequence photos, exposures by remote electronic control units, cable or radio releases.

Photo sequences of 2 frames per second are possible with the Motor-Winder R4. The Motor-Drive R4 has 4 frame per second capability but can also be switched to 2 frames per second or single exposures. A convenient switch can select the 2 frame per second sequence while exposing. All shutter speeds can be used. The Motor-Winder uses six, the Motor-Drive ten, standard alkaline batteries or rechargeable NiCad batteries. The battery housings can be exchanged in seconds. In extreme cold, the housing can be kept body-warm and connected with the Motor-Winder or Motor-Drive with a remote connection. Also, it is of great advantage during very cold weather that the power supply of the Motor-Winder and Motor-Drive, when attached to the camera, furnish the supply current for the camera as well.

And yet another point: Even when the LEICA R4 is operated by Motor-Winder or the Motor-Drive R4, aside from the normal shutter and mirror function they are hardly audible. Experienced photographers, particularly professionals, find this especially valuable.

Motor-Winder and Motor-Drive are coupled to the LEICA R4 housing and merge into an integrated unit. Single exposures are released via the shutter release. Photos in series are released via the release button on the Motor-Winder or Motor-Drive alternatively via electrical cable release or remote control. The system shuts off automatically after 36 exposures via Motor-Winder.

Motor-Winder and Motor-Drive in combination with the Remote Control-R unit

The electronic remote control unit RC LEICA R offers a number of very delightful possibilities. It serves as the remote release for the Motor-Winder and Motor-Drive and in conjunction with the automation of the LEICA R4 opens up new dimensions of photography. The control unit fits comfortably in one hand. It can be operated by the left hand equally well as with the right hand. All controls and the function displays are visible and available on the top.

The LEICA R-system: The basis for optimal adaptation of a camera system to any task and situation

The LEICA R4 is the heart of the universal LEICA R-System. Its high quality lenses, systematically matched in focal length and speed are equally important. They are the result of many years of experience in the Leitz glass research laboratory and of more than 140 years of Leitz tradition in the manufacture of high-quality optical-mechanical precision instruments. Accessories for photomicrography, macrophotography and copying have also been developed to solve most problems and cope with all situations. The wide range of lenses extends from the Fisheye to the Vario lens; from the distortion-free 15mm ultra-wide angle lens to the 800mm tele lens. In science and industry, when used with night vision instruments or with the Universal Focusing Bellows - the LEICA R4 is easy and simple to operate.

All current lenses of the LEICA R3/R3-MOT system can be used with the LEICA R4 without modification, therefore, all owners of these lenses have easy access to the most modern state of the art in camera technology.

Manufacturer description #4

All lenses of the LEICA R 3 / R 3-MOT range can be used on the LEICA R 4 without modification, but earlier 180 mm ELMARIT-R f/2 .8 (Code No. 11919) to Serial No. 2 939 700 and 250 mm TELYT-R f/4 (Code No. 11 920) to Serial No. 3 050 600 can only be used for aperture-priority with selective measurement, aperture-priority with largefield averaging and manual mode.

Lenses of the LEICAFLEX models must not be inserted in the LEICA R4 as this may lead to damage. For use in the LEICA R cameras they must be fitted with a control cam, when they will be suitable for use in both the LEICAFLEX and the LEICA R models (restrictions as above).

From the editor

Like the R3, this was another Minolta based camera.

Special limited editions (3)

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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

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

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

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.

Diffraction

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

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

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.

Flare

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.

Ghosting

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.

Anastigmat

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.

Transmittance

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.

14103

Replacement camera body cover, plastic, for all LEICA R-mount cameras.

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

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),

where:

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

Mount

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.

Speed

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.

Weight

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.

Filters

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

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.