Contax AX

35mm AF film SLR camera


Production details
System: Contax/Yashica (1975)
Imaging plane
Maximum format:35mm full frame
Mount and Flange focal distance:Contax/Yashica [45.5mm]
Imaging plane:36 × 24mm film
Model:Electronically controlled
Speeds:32 - 1/6000 + B
Exposure metering:Through-the-lens (TTL), open-aperture
Exposure modes:Programmed Auto
Aperture-priority Auto
Shutter-priority Auto
Physical characteristics

Manufacturer description #1

The Excellence of Carl Zeiss T* Lenses is Foremost in Consideration During the Design of the CONTAX camera.

This event marks the birth of the first auto focus SLR in the CONTAX line-up. Many photographers hold the concept that CONTAX cameras should be manual focus. This notion may derive from the desire that the Carl Zeiss T* lenses remain unchanged. But the tide of auto focus is strong and CONTAX could no longer remain without an AF SLR. Engineers rejected the idea early that the Carl Zeiss T* lens could be adapted to perform auto focus. As a result our Research and Development engineers have been working to find a solution that provides auto focus without changing the Carl Zeiss T* lens. Their solution, as expected, is elegant. The focusing mechanism is hidden within the camera body and the lenses remain unchanged.

A conventional approach to auto focus would require alteration of the Carl Zeiss T* lenses to accomodate such a system. Such alterations would diminish the exquisite performance of these lenses. Unequivocally, the Planar T* 85mm f1.4 could not be modified and still maintain its incredible performance. Lighter weight materials would decrease the longevity and stability of the optical package, looser tolerances would lead to decreased performance. Neither is acceptable to Carl Zeiss.

Unconventional solutions are required. CONTAX engineers developed the Automatic Back Focusing System to facilitate auto focus with no change to the legendary Carl Zeiss T* lens, whatsoever. The Automatic Back Focusing System achieves focus by moving the film plane forward and back via a ceramic rail and Ultra-Sonic motor. Both auto focus and manual focus co-exist in the same camera body with no degradation to either system.

The CONTAX AX debuts as an uncompromised imaging solution for the quality conscious photographer. The excellence of the Carl Zeiss T* lens is preserved.

A Dream Come True

An Auto Focus System That Maximizes the Optical Integrity of Carl Zeiss T* Lenses.

An Advanced Approach-Automatic Back Focusing System

Although moving the film plane has long been normal for large format (4x5 and 8x10) cameras, the greater precision, e.g. shorter working distance, and smaller circle of confusion have precluded such an approach in 35mm photography.

The AX marks the first time such an approach has been applied to a 35mm SLR. Miniaturization and extreme precision combine with ceramic and UltraSonic motor technology to create an auto focusing solution worthy of the name CONTAX.

The normally fixed mirror box, pentaprism assembly and film plane move as a unit in the AX. This chassis moves back and forth minutely on a ceramic rail to achieve focus. Virtually, a camera inside a camera. The subject is seen normally in the viewfinder while a TTL Phase Difference Detector commands the movement of the inner camera body to move the focus. The CPU receives data from the AF sensors and relays the command to energize the UltraSonic motor, moving the chassis forward or back to achieve focus. The use of two rigid bodies, one inside the other, is a revolutionary approach that provides a silent, extremely accurate, and high speed auto focusing response.

Enhanced Harmony Between Manual and Auto Focus

Since the lens is free from the auto focusing mechanism in the CONTAX AX (unlike other AF SLR systems), greater flexibility is possible. The auto focus system is engaged simply by turning a switch on the camera body. In the manual focusing mode, auto focus may be momentarily engaged with the touch of a button to confirm or assist manual focus. The CONTAX AX offers an unconventional focusing approach that harmonizes manual focusing with "instantaneous" inner body auto focus.

* Auto focus photographs are normally made with the lens set to infinity, however, for close up photography with long focal length lenses, the lens may be focused to a closer focusing distance.

* FIoating element/group lenses require that the movable chassis be set at the base position (shown via the back focusing scale indicator in the viewfinder).

* With zoom lenses, the focal length should be selected before using the auto focus system

A Wider Range of Lenses Allow Macro Photography

Other CONTAX SLRs have the film plane fixed at 45.5mm from the lens mounting flange. The AX (with its 10mm inner body movement) provides a movable film plane from 45.5 to 55.5mm eliminating the need for a 10mm extension tube to obtain closer focus. When the AX is placed into the Macro mode the film plane automatically shifts to the maximum extension position creating the most magnification.

Movable Chassis Position Shown in Viewfinder

An LCD indicator in the bottom of the viewfinder clearly shows the position of the back focusing system chassis. The bright, easy to use, full information viewfinder of the CONTAX AX includes focusing direction indicators, exposure compensation, aperture, shutter speed, exposure counter, flash ready indicator, back focus position indicator and exposure warning. All of the creative controls are visible in the viewfinder for quick decision and control.

Creative Photographic Tools for Sensing and Interpreting Light

Three metering systems in pursuit of the ultimate in exposure control

CONTAX photographers demand the highest quality in exposure control solutions. Therefore, the AX offers several solutions each optimized for different lighting situations.

Center-weighted average light metering

Considered the most suitable light metering system for general photographic situations It is best in situations where the subject is positioned in or near the center of the frame. The sensing area and subject weighting are unique to the CONTAX system having been honed over many years of continual refinement

Spot Metering

For complex lighting situations, the spot metering system is often the choice for professional photographers. A small area measuring only 5mm (approximately the size of the microprism spot in the center of the focusing screen.) pin-points specific areas of the composition for precise exposure control.

TTL Direct Flash Metering

For flash photography with the CONTAX TLA Flash system, the metering mode automatically switches to through-the-lens (TTL) direct flash metering. This system utilizes a Silicon Photo Diode (SPD) to read the light reflected directly off the film. The CPU interprets the data and feeds instructions to the flash luminosity control circuit.

Custom Functions for Personal Photographic Interpretation

Many settings may be customized on the AX to tailor the camera to the phogorapher's artistic desire.

Newly Developed, Larger Pentaprism

The CONTAX AX utilizes a new and particularly large pentaprism to optimize both the field-of-view and viewfinder brightness. The pentaprism is especially designed to meet the challenges imposed by the movable inner chassis. Aberrations and flare are reduced to even lower levels with this new configuration.

High Performance SPD and Ultra-precise Aspherical Lens

An in-board SPD element offers an extra high degree of metering accuracy. This cell type is characterized by a lack of temperature sensitivity and low memory The SPD is coupled with an aspherical lens to ensure sharp incident light convergence on the cell surface

Advanced Technology Assures the Highest Performance

Unique "Body Within a Body" Construction

The Automatic Back Focusing inner body composed of the mirror box, shutter, pentaprism and film chamber moves to gain focus within the fixed outer body.

Ceramic Technology, a Kyocera Specialty, Creates A Fine Ceramic Rail that Enables the Automatic Back Focusing System

The Automatic Back Focusing System ensures a stable, extremely smooth, high precision auto focusing movement due to the implementation of a matched pair of ceramic components. This matched ceramic collar and rail supports the movable chassis with virtually perfect alignment. The hardness of the ceramic material is near that of a diamond providing a wear-free surface that will last a lifetime. The fit between the ceramic collar and rail allows only approx. two microns of clearance. This extremely close tolerance assures that alignment problems will be eliminated.

Ultrasonic Micromotor Offers Silent, Refined Control

An exceptionally high torque, low rotation, ultrasonic motor was especially developed that requires but 1.5 turns of the motor shaft to drive the Automatic Back Focusing System through its full 10mm range. Speed reduction devices are unnecessary in the CONTAX AX since the direct drive ultrasonic motor used in the Automatic Back Focusing System provides extremely accurate, silent and almost instantaneous movement.

A Titanium Top Cover and Aluminum Alloy Die-Cast Chassis

A super durable, titanium top cover adds rigidity to the exterior body. Both the inner and outer chassis of the CONTAX AX are constructed of die-cast aluminum alloy.

High Speed Data Processing Integrated With Stable Digital Control Circuitry

Higher data processing speeds are required to assure the quality of the auto focus system. The CONTAX AX achieves this high data processing speed through parallel control of three CPUs (single chip packages for light metering, luminosity control and distance measurement).

High Speed 1/6000 Sec. Shutter

A wide range of extremely accurate shutter speeds are available. Sports photography is easy with the 1/6000 second top shutter speed At the other end of the scale, timed exposures can be up to 32 seconds long, automatically. Flash fill photography is easy with any shutter speed up to 1/200 second X synch shutter speed. The CONTAX AX employs a vertical travel, multi-blade shutter for long life and high reliability.

Manufacturer description #2

Type: 35mm focal-plane type AF single-lens reflex camera

Picture Size: 24 x 36mm

Lens Mount: Contax/Yashica MM Mount

Shutter: Vertical-travel focal-plane shutter

Shutter Speeds: 32 sec. - 1/6000 sec. at "Av" and "P"; 4 sec. - 1/4000 sec. at "Tv"; B, X (1/200 sec.), 4 sec. - 1/4000 sec. on manual

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

Self-timer: Electronic self-timer; the shutter trips at 2-sec. or 10-sec. delay

Shutter Release: Electronic release, provided with special cable switch socket

Focusing System: Manual and auto focus

Autofocus: Automatic back focusing system with TTL phase difference detection. Focus detection range (ISO 100): EV2-21. Autofocus modes: SAF (single autofocus) and CAF (continuous autofocus)

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

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

Metering Range (ISO 100, f/1.4): EV0-21 on TTL center-weighted average light metering, EV3-21 on spot metering

Film Speed Range: ISO 25-5000 for automatic setting with DX code, 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-step 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

Flash Synchronization: In combination with dedicated flash, the shutter speed is automatically set when the flash is fully charged

Automatic Flash setting: Possible in combination with dedicated flash capable of automatic flash setting

Second Curtain Synchronization: Possible in combination with dedicated flash capable of second curtain synchronization

Viewfinder: Pentaprism eye-level finder (long eye-point type): Field-of-view 95%, magnification 0.7X (with 50mm normal lens at infinity, -1D diop.)

Diopter Adjustment: Built-in diopter adjuster, correctable range +0.5D to -2.0D

Focusing Screen: Horizontal split-image/microprism type (FW-1) (standard), interchangeable screens (FW type) are also available

Display in Viewfinder: Focus display, shutter speed, exposure warning, aperture value, exposure mark, back focusing scale, A.B.C. mode, exposure compensation, metering mark, exposure counter/self-timer remaining time, flash mark

Display Panel: Exposure counter/film speed/remaining time before the shutter trips on self-timer/elapsed time on bulb exposure, multiple exposure mark, custom function mark, battery warning mark, film mark, DX number of exposures

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

Film Advance: Automatic winding with built-in motor

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

Drive Modes: Single-frame, continuous (CL and CH), self-timer (2 sec. and 10 sec.), multiple exposure

Winding Speed: Up to approx. 5 frames/sec. on continuous shooting ("CH" mode) (with a new battery, at ordinary temperature, as tested according to Contax testing standard)

Exposure Counter: Display panel and viewfinder, both automatically resetting, additive type

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

Custom functions: Exposure check button-function; Switching of multiple exposure setting method; Switching of A/B/C shooting order; Switching of aperture stop-down button operation method; Remaining film at the time of film rewinding; Rewind at the end of film; Turning on of AF supplementary light; Electronic sound when subject is in sharp focus (SAF)

Camera Back Cover: Can be opened with camera back release lever; detachable

Power Source: One 6V lithium battery (2CR5)

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

Battery Capacity: About 50 rolls of 36-exposure film (with a new battery, at ordinary temperature, as tested according to Contax testing standard)

Others: Aperture stop-down button, socket for external power source


This camera incorporates an automatic back focusing (ABF) system which enables auto focusing with conventional Carl Zeiss lenses for Contax SLR cameras. This autofocus SLR is also a combined auto/manual focusing camera. So you can focus the lens manually by using the distance ring of the lens.

In addition, it offers many other advanced features as follows:

  1. This is a multi-mode SLR camera which provides various exposure control functions such as aperture-priority auto exposure, shutter-speed-priority auto exposure, and programmed auto exposure.
  2. When taking pictures on manual focusing or taking macro pictures, you can check the sharpness of your picture on the focus display.
  3. With the "custom functions", it allows you to set the camera's operating conditions suited to your own use.
  4. In combination with our CONTAX TLA flash with automatic flash setting feature, the film speed and aperture value which you have set on the camera will also be set automatically to the flash unit.
  5. Equipped with a Contax Data Back D-8 (optional accessory), the camera can record exposure data collectively on the first two frames (or on one frame) of the film or dates and exposure data between the frames. Interval shooting is also possible.
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35mm full frame

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

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Image stabilizer

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

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

Original name

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


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

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

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

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

Angle of view

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

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

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

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


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


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

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

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

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

Lens construction

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

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

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

Focal length

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


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

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

Closest focusing distance

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

Closest working distance

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

Magnification ratio

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

Manual 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.