Pentax 645

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Pentax 645
Pentax645.jpg
Type: Medium format single lens reflex camera in the format 60 mm × 45 mm
Production period: 1984-1997
Lens connection : Pentax 645 A bayonet
Film format : 120 roll film, 220 roll film and 70 mm film
Recording format : 56 mm × 41.5 mm
Viewfinder : Keplarisches telescope with pentaprism
Viewfinder field: v 92%, h 93%
Enlargement: 0.75 times
Finder Ads: LED for time, aperture, flash readiness and exposure warning
Operating modes: P, Tv, Av, M, B, X
Film transport: Electrically and manually possible
Frame rate : 1.5 frames per second (fps)
Exposure metering : TTL with aperture open, center-weighted
Measuring range: EV 3 through EV 19
Correction : +/- 3 EV
Closure : electronically controlled, vertically running cloth slit closure
Shutter speed : 1/1000 s to 15 s, 1/60 s and B
Control: electro-magnetic
Flash control: TTL flash mode with film surface measurement
Lightning connection : Hot shoe and PC socket with x-synchronization
Synchronization : 1/60 s
Power supply: 6 × 1.5 V AA batteries (LR6) and 1 × 3 V lithium battery (CR1220) for the memory
Casing: Metal housing, plastic top cap
Dimensions: 141 mm × 109 mm × 117 mm
Weight: 1280 g

In 1984, Asahi Pentax launched the Pentax 645 , a handy medium format camera with an image format of 60 × 45 mm. Along with the 6 × 7 released in 1969, it is the second medium format camera model for Asahi Optikal KK. It was produced until 1997 and replaced by the 645N.

General

The Pentax 645 is a medium format single-lens reflex camera from the Japanese company Asahi Optical KK for roll film . Depending on the film cassette, 120, 220 and 70 mm roll film are used as films.

A new bayonet for the 645 lenses is also introduced with the camera. The bayonet has electrical contacts for transferring lens information, similar to the Pentax A series, which was released 1 year earlier . This made it possible to equip the cameras with automatic aperture and program controls. The new functions from the Pentax 35mm camera series have also been incorporated into the 645. So one has orientated oneself to the operating concept from ME super and program A, the settings are all done via buttons. The flange focal length is 70.87 mm and is therefore shorter than that of the Pentax 6 × 7 format, so that the Pentax 6 × 7 lenses can be used on the new camera using an adapter that was also developed.

The Pentax 645 is a so-called multi or multiple machine. The camera has a program, time and aperture automatic, tracking measurement, programmed automatic flash and a TTL flash control. In addition, it has a fixed X sync time and bulb mode for long exposure. With its electromotive film transport and 7 types of exposure, Asahi Optikal KK brought one of the most advanced medium format cameras onto the market at the time.

The films are loaded in a film insert corresponding to the film, which enables a quick film change. The film inserts are kept in a suitable container until they are used. The film transport is motorized. It is not easy to change the film cassette in between. The Pentax 645 has a detachable battery grip on the right side, which is also where the trigger is located.

Data and equipment features

Controls

On the top of the camera, on the right shoulder next to the viewfinder, there is a three-part LCD panel, to the right of it, a little deeper on the edge of the housing, there are two buttons for selecting the type of exposure, exposure time, aperture, film sensitivity, exposure compensation and the program mode.

There are 5 touch buttons on the left shoulder of the camera. The 2 touch buttons next to the viewfinder are used to switch on the viewfinder display and to illuminate the LCD panel. The three push buttons on the left outer edge are used to select exposure correction (top), ISO selection (middle) and program mode (bottom). Below the left shoulder on the back wall there is a selection dial to switch between single (S) and series (C) pictures.

The battery grip with the release button is attached to the right of the camera housing. To the left of the release button there is a main switch that switches off the batteries in the handle to prevent accidental release. There are 6 AA batteries (LR6) in the handle , they are used to supply the film transport motor and the locking mechanism. The program control and displays are supplied by a 3V button cell type CR 1220 in the camera base.

The dimming lever is on the right side of the camera on the front edge.

On the left side of the camera, in the front third, there is a tripod thread for portrait format recordings. Above it at an angle to the left is the mount for the manual film transport wheel. The PC socket with X synchronization is located on the rear edge below the left camera shoulder. Below is the multiple exposure ring and the cocked shutter indicator.

The lens mount is on the front. The lens release is located on the lower left of the bayonet.

The tripod thread is located in the front third of the underside. The compartment for the emergency transport bike is located directly behind it. The battery compartment for the storage battery (CR 1220) is located next to the tripod thread. At the rear left is the connection socket for electrically coupling the housing and battery handle. There is also a connection cable with which you can remotely control the camera from up to three meters with the battery grip removed.

The battery handle has an additional socket on the underside for connecting an external battery container. Next to it is the unlocking screw for removing the handle.

Clasp

The closure is a vertically running cloth slit closure. It consists of polyester-reinforced treadmills and two closing curtains, also polyester-reinforced.

The shutter is electronically controlled and released electromagnetically. It allows shutter speeds from 1/1000 s to 15 s, 1/60 s as flash sync time and bulb.

Viewfinder

The viewfinder system is a non-exchangeable system, as was otherwise common with professional cameras at this time. The viewfinder of the Pentax 645 consists of a Keplar telescope with diopter correction at the viewfinder (eyepiece). The correction ranges from −5 to +2 diopters. It also consists of a pentaprism viewfinder with silver coating and a ground glass with a sectional image indicator and a microprism ring . The screen can be exchanged, you can choose from five variants.

The viewfinder coverage is 92% vertically and 93% horizontally of the film format and offers a magnification of 0.75 × with a 75 mm lens in the infinity setting.

The LED display (red) for the time, aperture, exposure warning and flash readiness is located at the bottom right of the viewfinder. This is switched on and off using a push button on the left shoulder of the camera.

trigger

The camera shutter release is located on the top of the detachable battery handle. It is an electromechanical button with two pressure points, light tapping activates the exposure measurement, pressing it down electrically triggers the shutter. In addition, it has a connection thread for an electrical or mechanical remote release.

Measurement system and displays

The camera has a center-weighted TTL open aperture measurement through the lens using GaAsP photodiodes . The measuring range is from EV  3 to EV 19.

With internal flash measurement (TTL flash control), the film surface is measured.

The exposure is displayed via a red LED display in the lower viewfinder frame and via an LCD field on the right shoulder of the camera. Switchable lighting can be activated via a button on the left shoulder of the camera and makes reading easier.

In the three-part LCD field, the mode (automatic, manual, bulb), the program, the automatically or manually set exposure times and aperture values ​​as well as the flash readiness are displayed in the large upper field. In addition, the iso value is displayed here if this is set.

The exposure compensation is displayed in the lower left field. The lower right field shows the exposures made (image counter).

power supply

The camera is supplied with 6 × 1.5 V AA batteries LR 6 for film transport and shutter, and a 3 V lithium battery CR 1220. Alternatively, an external battery container can be connected to the handle. This is particularly recommended in cold temperatures, as the batteries can be stored in a warm bag.

Lenses

The lens program for the Pentax 645 was already extensive for a medium format system at that time. When it appeared, Asahi Optikal KK released 8 lenses and a converter:

Prime lenses Zoom lenses converter
SMC Pentax-A 645 45mm f / 2.8 SMC Pentax-A 645 80-160mm f / 4.5 Tele converter 645-A 1.4 ×
SMC Pentax-A 645 55mm f / 2.8
SMC Pentax-A 645 75mm f / 2.8
SMC Pentax 645 LS 75mm f / 2.8

Central locking

SMC Pentax-A 645 150mm f / 3.5
Smc Pentax-A 645 200mm f / 4
SMC Pentax-A 645 300mm f / 4

More were added later:

Zoom lenses converter
SMC Pentax-A 645 35mm f / 3.5 SMC Pentax-A 645 45-85mm f / 4.5 Teleconverter 645-A 2.0x
SMC Pentax-A 645 120 mm f / 4 Macro
SMC Pentax 645 LS 135 mm f / 4

Central locking

SMC Pentax-A * 645 600mm f / 5.6

equipment

  • Asahi Pentax has an automatic bellows device 645 , an intermediate ring set-A 645 , a macro worm 645 , a bayonet ring 645 and a reversing ring 645 .
  • Angle finder 645, eyepiece adapter, adapter for using the 6 × 7.
  • When released, there are 3 system-compliant flash units from Asahi Pentax that have a hot shoe; older flash units can be used with restrictions.
  • Asahi offers a 3-channel infrared remote control system.
  • There are 3 film inserts for 120, 220 and 70 mm film. The 70 mm film insert includes an eyepiece extension for viewing the viewfinder.
  • Cable release A, hot shoe adapter LS, external battery case

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