Contax ST

35mm MF film SLR camera

Specification

Production details:
Announced:1992
System: Contax/Yashica (1975)
Format:
Maximum format:35mm full frame
Film type:135 cartridge-loaded film
Mount and Flange focal distance:Contax/Yashica [45.5mm]
Shutter:
Type:Focal-plane
Model:Electronically controlled
Speeds:16 - 1/6000 + B
Exposure:
Exposure metering:Through-the-lens (TTL), open-aperture
Exposure modes:Programmed Auto
Aperture-priority Auto
Shutter-priority Auto
Manual
Physical characteristics:
Weight:800g
Dimensions:151.5x97.5x55mm

Manufacturer description #1

Sometimes one needs to stand back and re-survey the situation, to view the subject from an entirely new angle The CONTAX ST was born out of employing this very approach, blending a perfect mix of new technologies with tried-and-true photo-optical mechanisms crafted to a new level of reliability. Creativity should be in the hands and eyes of the photographer, and this true masterpiece of precision performance is a breath of fresh air, the quintessential tool to complement and extend one's level of creative achievement.

A Name Rich in Tradition and Excellence

When one says "CONTAX," it conjures up an image of trust; over sixty years of photographic excellence which advanced amateur and professional photographers have come to respect and rely on. The CONTAX ST follows in this great tradition by providing a new level of conveniently simple camera operation in concert with a superbly engineered body that truly complements the outstanding optics of Carl Zeiss T* lenses. Beneath the stylish body lies a full range of unseen improvements to the many traditional mechanisms which give this 35mm SLR camera that extra level of perfection CONTAX lovers have come to expect. Here is an "orthodox" camera providing the ideal mix of high priority photographic features based on built-in reliability, catering to all forms of photography.

High Speed Precision Control; Exclusive Pressure Plate

Silent, ultra-stable high-speed 1/6000sec. shutter. By incorporating a vertically running metal focal plane shutter which offers the highest degree of smooth, stable movement over a wide range of speeds, extra "high speed" versatility has been realized. Extra quiet and fast for even the most sensitive nature photography, there is the added edge of high performance and accuracy for sports or special effects. Plus, the superior precision at wide open apertures optimizes the special characteristics of Carl Zeiss T* lenses.

Fine ceramic pressure plate for more perfect film flatness Developed by Kyocera engineers specifically for CONTAX cameras, this ultra durable, fine ceramic pressure plate represents the cutting edge of fine ceramic technology, especially as applied to camera design and film flatness. With the CONTAX ST, it is just this extra degree of flatness and superb surface finish that allows the photographer to capitalize fully on the renowned performance of the wide range of Carl Zeiss T* lenses. Further, as shown below, the fine ceramic plate (composed of material initially engineered at the molecular level) has many superb properties, such as being close to diamond hardness, capable of withstanding strong external pressures and environmental shifts, plus being virtually warp, erosion and ageing free. A CONTAX first found in no other brand of cameras.

High power, precision, reliable drive mechanism

Engineering advances have allowed an added degree of mechanical simplification, which when combined with a high torque, low noise, coreless motor to drive the film and prime the shutter, have resulted in enhanced reliability and durability.

An improved sprocket drive offers an extra degree of winding precision that enables data to be imprinted between frames.

Creative Exposure Control Lets the Photographer Build the Image

Very versatile light metering system choice

No one exposure determination method has yet been devised that can handle all cases presented by the infinite nature of light and film emulsion characteristics Indeed, maybe the CONTAX ST approach could be called conservative, but it takes the two light metering systems most preferred by professionals and allows them to be switched quickly and easily. Thus the photographer can precisely measure the available light and make the creative exposure choice to fashion the final image from a combination of reality and imagination .

Center-weighted average metering

This is the most widely employed metering method, by far, because of its overall accuracy and ability to handle a full range of general photographic conditions. Tried and true, it still remains the preferred method of exposure measurement for everyday applications.

Spot metering

To complement the center weighted average measurement method, the CONTAX ST also includes a spot metering function which can be quickly employed when the photographer needs extra-accurate, real time light measurement from a finely defined spot equivalent to the 05mm microprism area in the center of the focusing screen. This serves as an invaluable tool for making comparative readings of elements within a picture, necessary for creative decisions such as whether to expose for well lit portions, shadow definition or somewhere in between. As shown to the left, in the CONTAX ST, the dual (center weighted average/spot) light metering module (ultra precise aspherical lens+SPD package+lC) is situated just behind the pentaprism and above the eyepiece.

TTL direct flash metering

When a CONTAX dedicated flash unit is mounted on the CONTAX ST, TTL direct flash illumination control automatically comes into play. As shown on the left, light from the subject reflected off the film plane is measured by an SPD below the mirror and fed to the CPU control circuit that determines the correct duration of the emitted flash. Thus this highly sophisticated system automatically ensures perfect flash illumination of the subject.

High-performance SPD package & ultra-precise aspherical lens

Enhanced light metering accuracy is ensured through the incorporation of the most technologically advanced SPD package coupled to a dedicated aspherical lens. The former offers superb performance across a wide temperature spectrum as well as high durability, while the latter serves to condense the incident light reaching the SPD, thus greatly minimizing the chance of metering error.

Excellence in Viewfinder Optics

Oversized pentaprism for unsurpassed subject visibility

The CONTAX engineering team placed high priority on making the viewfinder as bright as possible. Accordingly, it was decided to incorporate the luxury of an oversized, high performance pentaprism. Its optical purity delivers a really bright, faithfully transmitted color image with aberration, ghosting, and flare reduced to the barest minimum. Already praised by CONTAX professionals, this viewfinder allows one to envisage the superb clarity and perfection of Carl Zeiss T* lenses.

Extra-clear, easily focused, informative long eyepoint viewfinder

Increased finder image brightness sometimes causes the focus to peak too sharply, or on the other hand, when diminished, makes focusing difficult. The CONTAX ST's specially designed finder overcomes these problems admirably. The image is highly visible, easily, speedily framed and focused, plus even at the viewfinder periphery, a high degree of focusing accuracy can be achieved. Additionally, all the necessary creative information is visible within the viewfinder, below or to the right of the image field. As the exposure counter, spot metering mark, aperture value, flash status, over exposure warning, shutter speed, and exposure compensation warning are all easily checked while looking through the finder, the photographer can make creative decisions and confirm them while constantly watching the subject. Plus, the brightness of the LEDs changes to match that of the viewfinder to avoid distracting the photographer from the subject.

Illuminated controls for low-light shooting

Three of the "extras" that make handling the CONTAX ST more convenient, are the large sized controls, exposure mode indicators (windowed) and LCD panel, all of which can be illuminated when the light is low. Pushing the dedicated button activates subdued lighting of the exposure compensation dial, shutter speed dial, exposure mode indicators, and LCD panel. Thus photographic creativity is not hampered when working under poor lighting conditions.

A CPU Nerve Center for Simplified Total Control

Error-free programming delivers speedier performance

Greatly simplified programs delivering faster responses by single chip, high performance CPU circuitry, control all the CONTAX ST systems. By simulating all camera operations, the design team also incorporated compensation factors to eliminate problems, such as, the chattering of all mechanical contacts, thus creating software that is virtually free from error in use.

Low impedance circuit eliminates conventional metering errors

By lowering the electronic circuitry impedance in the CONTAX ST, influence from external noise has been greatly reduced. In conventional cameras signals are transmitted through wires from an SPD to an analog IC, and are thus prone to influences from noise. In the CONTAX ST, the SPD and processing system have been integrated into a single metering IC (eliminating the wires between the two), and data in the form of voltage signals is transmitted to the CPU. Thus compared to conventional light metering systems, a far higher degree of accuracy is possible.

Digitized signal processing enhances accuracy & reliability CONTAX engineers, having earlier developed circuitry for the RTS III which employed digitized signal processing, decided to follow this approach in the ST. Not only are camera circuitry weak points, associated with analog signal transmission, eliminated, but also heightened signal stability, realtime response, finer adjustments and higher accuracy can be achieved. Conventional metering systems average values accumulated by every 10 msec. to reduce the influence of flickering by fluorescent lighting, but with the CONTAX ST the CPU performs a higher frequency sampling/averaging to enable real time response to light variations. Additionally, ISO film speed, aperture and internal final adjustments are automatically, speedily computed and controlled by the CPU. Accordingly, not only are delicate adjustments not conventionally possible available, but the circuitry is far less prone to that deterioration normally associated with aging, thus ensuring long-term stability. Further, through CAD (computer aided design) application, the flexible circuit layout has been rationalised thereby shortening the travelling distance of the signals.

Superior quality components

Abundant use of a full range of high performance devices, many resulting from Kyocera's in house developed electronic technology, increases the camera's durability and performance. All circuit contact points (especially brush) are gold-plated to ensure greater reliability, surer contact, as well as minimized abrasion and aging. The aperture information brush utilizes a specially designed system where it rides over leads drawn out from resistor contact points rather than contacting the resistors directly. Thus the resistance value doesn't change even after extended, repetitive actions. Also, the CONTAX ST unique two-step release button has superior durability and performance even over the best mechanical, simple one step switch.

Perfectly balanced, super-durable high precision diecast body

Contrary to the trend to employ composite plastic material to enable lightweight camera construction, the CONTAX ST aims for optimal body durability and weight to act as a counterbalance especially for large aperture/ long focal length lenses. Professionals favor a rugged camera able to withstand external knocks and prolonged vibration in transit and the CONTAX engineers felt that only conservative, metal alloy construction would do. They decided that a copper silumin alloy could be diecast and high temperature/pressure steam annealed to realize the ultra precision/distortion free camera body performance they desired even over extended, hard use. Further, advanced CAD simulation was applied to develop a body configured for overall maximized strength. Also, the stainless steel mount fastened in place with screws at six points ensures added reinforcement plus extra secure lens coupling.

Brass alloy offers a high level of absorption of extended shocks

In addition to the highly durable body, top and bottom brass alloy covers enclose the CONTAX ST for added body rigidity, further isolating and protecting the delicate inner working mechanisms. Extra durable metal materials are also used for the grip and front cover.

Manufacturer description #2

Type: Auto-exposure 35mm single-lens reflex camera with focal plane shutter

Picture Size: 24 x 36mm

Lens Mount: Contax/Yashica MM Mount

Shutter: Vertical-travel metal focal-plane shutter

Shutter Speeds: Automatic modes.... 16 sec. - 1/6000 sec. at "Av" and "P"; 1 sec. - 1/4000 sec. (setting values) at "Tv"; Manual mode.... B, X (1/200 sec.), 1 sec. - 1/4000 sec.

Sync Contacts: Direct X contact (synchronizing speeds 1/200 sec. or slower), provided with sync terminal

Self-timer: Electronic self-timer with a 10-sec. delay

Shutter Release: Electromagnetic release, provided with a special release socket

Exposure Control: 1. Aperture-priority auto exposure. 2. Shutter-speed-priority auto exposure. 3. Programmed auto exposure. 4. Manual exposure. 5. TTL auto flash control. 6. Manual flash control.

Metering System: TTL center-weighted average light metering/spot metering switchover

Metering Range: EV0-20 on center-weighted average light metering, EV4-20 on spot metering (ISO 100, f/1.4)

Film Speed Range: ISO 25-5000 for automatic setting with DX film, ISO 6 - 6400 for manual setting

AE Lock: The quantity of light on the image surface is stored in memory

Exposure Compensation: +2EV to -2EV (can be set in 1/3-EV increments)

A.B.C. Mode: +/-0.5EV to +/-1.0EV exposure compensating values with A.B.C. lever

Flash Light Control: TTL direct flash control

Automatic Shutter Speed Switching: In combination with dedicated flash, the shutter speed is automatically set when the flash is fully charged

Second Curtain Synchronization: Possible with Contax flash having a second curtain synchronization capability

Viewfinder: Pentaprism eye-level finder (Long eye point type), approx. 95% field of view, approx. 0.8X magnification (with 50mm lens at infinity and -1D diop. eyepiece)

Diopter Adjustment: Built-in diopter adjuster, correctable range +1D to -3D

Focusing Screen: Horizontal split-image/microprism type (standard), interchangeable screens available

Display in Viewfinder: Shutter speed, aperture, overexposure/underexposure warning, A.B.C. mode, exposure compensation, metering mode, exposure counter, flash mark

Display Panel: Exposure counter/film speed/remaining time on self-timer/elapsed time on bulb exposure, drive modes (single-frame exposure, continuous shooting, self-timer), battery warning mark

Film Loading: Auto loading, automatic film positioning to "01" on counter

Film Advance: Automatic winding with built-in motor

Film Rewinding: Automatic rewinding with built-in motor, automatic stop after rewinding is completed, mid-roll rewinding possible

Exposure Counter: On display panel and viewfinder, both automatically resetting, additive type; displays the A.B.C.

Accessory Shoe: Direct X-contact hot-shoe (provided with TLA flash contact)

Drive Modes: Single-frame exposure, continuous shooting, and self-timer modes

Winding Speed: Up to about 3 frames/sec. on continuous shooting ("C" mode) (with new AAA-size alkaline batteries, at ordinary temperature, as tested according to Contax testing standard)

Camera Back: Can be opened by camera back opening lever; detachable; provided with data back and film check window

Data back: Built-in quartz clock (auto calendar), dates are printed in a space between frames (outside the picture area) simultaneously with film winding

Power Source: Four AAA-sie 1.5V alkaline batteries or four AAA-size 1.2V NiCd batteries, one lithium data-back battery (CR2025) in camera back

Battery Check: Automatic check, battery warning mark in display panel

Battery Capacity: About 50 rolls of 24-exposure film (with new AAA-size alkaline batteries, at ordinary temperature, as tested according to Contax testing standard)

Others: Aperture stop-down button

***

This camera is a multi-mode auto-exposure single-lens-reflex camera which offers various sophisticated features such as aperture-priority auto exposure, spot metering, 1/6000 sec. high speed shutter on auto, and 1/200 sec. flash synchronizing speed.

It also provides a large-size shutter speed dial which allows you to check the camera operation and information at a glance as well as an exposure mode selector lever for switching the operation quickly. The display can be illuminated when you take pictures in dim light.

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Copyright © 2012-2024 Evgenii Artemov. All rights reserved. Translation and/or reproduction of website materials in any form, including the Internet, is prohibited without the express written permission of the website owner.

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.

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.

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.