The Pentax MX was a 35 mm

135 film

The term 135 was introduced by Kodak in 1934 as a designation for cartridge film wide, specifically for still photography. It quickly grew in popularity, surpassing 120 film by the late 1960s to become the most popular photographic film format...

 single-lens reflex camera

Camera

A camera is a device that records and stores images. These images may be still photographs or moving images such as videos or movies. The term camera comes from the camera obscura , an early mechanism for projecting images...

 produced by Asahi Optical Co, later Pentax

Pentax

Pentax is a brand name used by Hoya Corporation for its medical-related products & services and Pentax Ricoh Imaging Company for cameras, sport optics , etc. Hoya purchased and merged with the Japanese optics company on March 31, 2008. Hoya's Pentax imaging business was sold to Ricoh Company, Ltd...

 of Japan

Japan

Japan is an island nation in East Asia. Located in the Pacific Ocean, it lies to the east of the Sea of Japan, China, North Korea, South Korea and Russia, stretching from the Sea of Okhotsk in the north to the East China Sea and Taiwan in the south...

 between 1976 and 1985.
It was Pentax's flagship professional SLR

Single-lens reflex camera

A single-lens reflex camera is a camera that typically uses a semi-automatic moving mirror system that permits the photographer to see exactly what will be captured by the film or digital imaging system, as opposed to pre-SLR cameras where the view through the viewfinder could be significantly...

 until the introduction of the Pentax LX

Pentax LX

The Pentax LX is a 35 mm Single-lens reflex camera produced by Pentax in Japan between 1980 and 2001. The lens mount is the Pentax K mount, allowing the use of almost all Pentax 35 mm format lenses, those made before 1975 using a screw-mount adapter with limited automatic functionality. ...

. Internally, the MX is essentially a smaller, lighter version of the Pentax KX, and otherwise has little in common with the rest of the Pentax M-series. However, the MX was designed as the mechanical twin sister of the remarkably successful entry-level Pentax ME

Pentax ME

The Pentax ME was an aperture priority automatic camera, with an electronic focal plane shutter from 8 s to 1/1000 s, synchronized at 1/100 s. The shutter curtains were metal and had a vertical movement. There was no shutter dial, and the camera could not be used in manual mode,...

.

The MX was solidly built, and featured a fully mechanical construction, including a mechanical shutter

Shutter (photography)

In photography, a shutter is a device that allows light to pass for a determined period of time, for the purpose of exposing photographic film or a light-sensitive electronic sensor to light to capture a permanent image of a scene...

 of the horizontal cloth type. Only the light meter

Light meter

A light meter is a device used to measure the amount of light. In photography, a light meter is often used to determine the proper exposure for a photograph...

ing system was dependent on batteries. The MX is all manual: it does not feature autofocus

Autofocus

An autofocus optical system uses a sensor, a control system and a motor to focus fully automatic or on a manually selected point or area. An electronic rangefinder has a display instead of the motor; the adjustment of the optical system has to be done manually until indication...

 or autoexposure modes such as aperture-priority, shutter-speed priority, or full program.

A number of accessories were produced, among those:
Focusing Screens

• SC1: ground glass, split image device, microprism ring (standard)
• SA1: ground glass, microprism patch
• SA3: ground glass, microprism patch, for wide aperture lenses
• SB1: ground glass, split image device
• SD1: ground glass, cross collimator
• SD11: aerial image, cross collimator
• SE: ground glass
• SG: ground glass, grid
• SI: ground glass, axis,

Data backs, Dial Data MX and a bulk film back.
Motorized winder Winder MX (2 frame/s) or a Motor MX (5 frame/s)motor drive

Motor drive

A motor drive, in the field of photography, is a powered film transport mechanism. Historically, film loading, advancing, and rewinding were all manually driven functions...

.

Like all post-42 mm screwmount

M42 lens mount

The M42 lens mount is a screw thread mounting standard for attaching lenses to 35 mm cameras, primarily single-lens reflex models. It is more accurately known as the M42 × 1 mm standard, which means that it is a metric screw thread of 42 mm diameter and 1 mm thread pitch...

 Pentax cameras, the MX accepts all K-mount

Pentax K mount

The Pentax K mount, sometimes referred to as the "PK mount", is a lens mount standard for mounting interchangeable photographic lenses to 35 mm single-lens reflex cameras. It was created by Pentax in 1975, and has been used by all Pentax 35 mm and digital SLRs since...

lenses (with the exception of the newer FA-J and DA lenses without aperture rings).

Due to its complete lack of automatic functions, but excellent array of manual controls, the MX is often selected as a camera for photography students to practice their technique. The depth-of-field preview function renders the MX superior in this one respect to the earlier and cheaper K1000.