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Contax 645 AF

Medium format AF film SLR camera


Production details
Announced:February 1999
System: Contax 645 (1999)
Imaging plane
Maximum format:Medium format 6x4.5
Mount and Flange focal distance:Contax 645 [64mm]
Imaging plane:56 × 41.5mm film
Model:Electronically controlled
Speeds:8 - 1/4000 + B
Exposure metering:Through-the-lens (TTL)
Exposure modes:Aperture-priority Auto
Shutter-priority Auto
Physical characteristics

Manufacturer description #1

Born with a reverence for the traditional, yet advanced beyond your dreams. The Contax 645 is poised for the 21st century.

This new century will bring many challenges and the 645 is ready for any of them. Autofocus backed by a precision manual focus system provides the ultimate in focusing flexibility. Film flatness problems are addressed for the first time in any medium format camera through the development of a Real Time Vacuum system. Of course, the unrivaled Carl Zeiss T* lenses are the stars of the system. These lenses offer unmatched resolution and distortion control while T* insures that contrast and color are unrivaled. In short, the CONTAX 645 represents the highest expression of technology in medium format cameras today and into the future.


A newly developed autofocus system and dual focus mechanism make it easy to control autofocus and manual focus.

Giving meaning to the capture of light in an image depends upon the sensitivity of the photographer. Based upon the premise that "the main element involved in creation of the photograph is the photographer", the Contax 645 offers a newly developed focusing system. Dual Focus controls autofocus and manual focus to meet the expectations of the photographer. This Dual Focus system allows the AF system to assist the manual system and the manual system to assist the autofocus system.

Without moving your eye from the viewfinder, the 645 may be changed from AF to manual and visa-versa. Autofocus uses a central TIL area sensor composed of four horizontal and two vertical lines, composing an array of 1/5-inch, 250,000 element CCD. Superior range finding accuracy is obtained.


A high-speed shutter coupled wit the high performance of Carl Zeiss T* lenses brings great flexibility to the photographer.

A larger film size leads to a larger shutter. Consequently, the fastest shutter speed of a conventional medium format camera has difficulty in achieving speeds as fast as those of a 35mm camera. The Contax 645 dramatically expands the range for taking photographs with medium format cameras.

The newly developed high-speed focal plane shutter is the most advanced shutter in this class. The Contax 645 achieves a high shutter speed of 1/4000 second and the fastest flash sync speed of 1/125 second. Higher shutter speeds allow the photographer greater freedom in selecting exposure.


The real-time vacuum system enhances film flatness, the biggest problem faced by medium format cameras

The biggest problem found in medium format cameras was film flatness. Film flatness becomes more difficult as the film area is increased. In particular, the open aperture of a fast lens produces an extremely shallow depth of focus. The slightest unevenness in the film degrades focus appreciably. As a result, conventional medium format photographers tend to produce stopped-down photographs. The Contax 645 provides a real-time vacuum system, highly valued in the RTS III, in the 6 x 4.5 size format. A striking improvement in film flatness can be achieved by installing the 220 vacuum film insert. Wide open apertures may be used with confidence.


Light metering system and exposure modes to faithfully reflect the intent of the photographer

The Contax 645 employs two types of light metering, center-weighted average metering which has excellent characteristics for general photography and spot metering suited to small area exposure settings. When the AE prism finder is installed, center-weighted average metering or spot metering can be used. The spot metering system installed in the body of the Contax 645 makes spot metering available even when the waist-level finder is installed. The exposure modes are aperture-priority AE, shutter- priority AE, and manual exposure. Additionally, the automatic bracketing control (AB.C) mechanism for automatically correcting the exposure in three consecutive frames is installed. Rapid, reliable photography is possible even for subjects requiring difficult exposure settings.

Center-Weighted Average Metering

Center-weighted average metering is well suited to typical photographs in which the main subject is close to the center of the image. By designing the optimum sensitivity distribution the camera is easy to use and can adapt to various photographic conditions. The center-weighted average metering block (high precision aspherical lens + SPD element + IC) is located in the AE prism finder.

Spot Metering

Spot metering is effective when you want to express the exposure with more precision and creativity than in ordinary light. Spot metering takes place in an area having a 5.5mm diameter in the center of the focusing screen, and usually operates along with the AE lock mechanism. This method demonstrates the power of the photographer with regard to placement of specific tones in a composition.

A.B.C. Mechanism

By merely switching the AB.C lever, this mechanism can offer three exposure variations: standard, over, or under exposure. The selectable corrections are ±0.5 EV and ±1.0 EV. Each exposure mode, except flash photography, is influenced by the A.B.C mechanism, spot or center-weighted, drive mode, AE lock, and the exposure compensation system are all handled. Even under delicate exposure conditions, photography is possible without becoming absorbed in exposure control decisions.


Pre-flash TTL light metering enables high quality photography

Determining the exposure for flash photography is normally a complex process. The pre-flash TTL metering system tests the flash output before exposing the film. This system frees the photographer from unstable factors such as metering errors caused by differences in film reflectance. Because the Contax system flash can remember the amount of emitted light that was automatically adjusted, the exposure can be controlled within later aperture adjustments. This system not only applies to Contax system flashes, but to general-purpose and studio flash equipment as well.


Finder system adapts to various photographic conditions and the objective of the photographer

The Contax 645 finder system can be adapted to match the objective of the photographer. The system provides two types of finders, the AE prism finder and waist-level finder. Three focusing screens are available, full matte (standard equipment), sectioned matte, and horizontal split-screen microprism.


A photographic data memory function is provided.

Reference data is recorded outside the image frame of the film, including aperture, shutter speed, exposure compensation, exposure mode, lens used, and film type.


Flash auto setting greatly expands the range of flash photography

When a flash, such as the TLA360 is attached to the accessory shoe of the AE Prism and switched to the Auto-set position, the film sensitivity data, aperture data, and lens focal length data are shared with the flash and shown on the display panel on the back of the flash. The illumination angle is automatically adjusted to match the focal length of the lens. In addition to exposure compensation in the body, the flash exposure can be adjusted for a more flexible flash fill. The Auto-set function improves communication between camera and the flash.

Manufacturer description #2

Lens mount: Contax 645 mount

Shutter system: Electronically controlled focal-plane shutter

Shutter speed: Auto - 32 seconds to 1/4000 second; Manual - 8 seconds to 1/ 4000 second, X (1 / 125 second); Bulb, mechanical bulb

Sync contact: X contact (synchronized at 1/125 second or lower). With direct X contact and sync terminal

Self-timer: Electronic, operating time switches between 2 and 10 seconds, can be canceled while running

Shutter release: Electronic release and dedicated release socket

Exposure control: 1. Aperture-priority auto exposure; 2. Shutter-priority auto exposure; 3. Manual exposure; 4. TTL auto flash; 5. Manual flash

Light metering - Standard TTL Metering: Center-weighted average metering, spot metering, pre-flash TTL light metering

Continuous light metering range (ISO 100, F2): Center-weighted average metering - EV 1 to 21; Spot metering - EV 3 to 18.

Film speed range: ISO 6 to 6400, Automatic using bar code system

AE lock: AE and focus lock

Exposure compensation: +2 EV to -2 EV (can be set in steps of 1/ 3 EV)

A.B.C. mechanism: 3-frame continuous exposure compensation, exposure compensation ranges of ±0.5 EV and ±1 EV

Flash link light adjusting: TTL direct light adjusting

Flash sync: The shutter speed is switched automatically when the dedicated flash is done charging.

Flash auto set function: This can be combined with the flash equipped with Contax's auto set function.

Shutter curtain sync: Can be combined with Contax's flash having a shutter curtain sync

Focus adjustment and range finding: Manual focus and auto focus (TTL phase difference detection) Distance detection range: EV 1 to 18 (ISO 100)

Finder: Interchangeable finder, AE prism finder. Field of view - 95%. Magnification - 0.8 times (long eye point) (for standard 80mm lens at infinity and -10 visual angle). Built-in visibility correction mechanism, +10 to -20 correction range

Focusing screen: Interchangeable screen. The full matte screen is standard.

Internal finder display: Battery warning mark, frame counter, time remaining on self-timer, A.B.C. indication/End of film indication/Custom function indication, metering mark, flash ready mark, focus mark, aperture, shutter speed, exposure meter

Film back: Interchangeable film backs. 120/220 film insert MFB-1A. 220 vacuum film insert MFB-1B

Film loading: Semi-automatic loading by matching the start position mark (with fast forward function until the first frame) and easy load system

Film winding: Automatic winding by a built-in motor (fastest speed is about 1.6 frames/second)

Drive mode: Single frame, continuous, self-timer (2 or 10 seconds)

Frame counter: Additive, automatic reset

Multiple exposures: Possible

Mirror up: Possible

Accessory shoe: Direct X contact (with TLA flash linked contact)

Data recording: Can record photography data outside of the image plane. Recorded contents - aperture, shutter speed, exposure compensation, exposure mode, name of lens used, type of film

Power supply: one 6 V lithium battery (2CR5)

Battery check: automatic check, displayed inside the finder

Other features: aperture button, external power supply socket

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Table of contents
Instruction manual

Copyright © 2012-2022 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.

35mm full frame

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

Travellers' choice


Among autofocus lenses designed for 35mm full-frame mirrorless cameras only. Speed of standard and telephoto lenses is taken into account.

Professional lens (Top class)

One of the best

According to lens-db.com; among lenses designed for the same maximum format and mount.

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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.

Electromagnetic diaphragm control system

Provides highly accurate diaphragm control and stable auto exposure performance during continuous shooting.

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.