Pentax LX

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The LX camera was Pentax's most advanced manual focus camera. Launched in 1980 to celebrate the 60th anniversary of Asahi Optical (thus the LX denomination), it was Asahi Pentax's contender for the professional segment of the 35mm SLR camera market, competing with the Nikon F3 and Canon F-1.
When introduced in 1980 it had many unique features and groundbreaking technologies--die-cast aluminum alloy body, titanium electromechanical horizontal-travel shutter, total body sealing, and Integrated Direct Metering (IDM)--all wrapped in a relatively small package. The LX was a modular system at only 565g, which included a whole system comprising from the start a series of accessories such as eight interchangeable viewfinders, twelve viewfinder screens, two motor drives, two data backs, wired or wireless remote control, and dedicated flashes in addition to the vast range of SMC lenses. It was protected against water and dust. This is probably one of the finest mechanical 35mm cameras ever produced, and very comfortable and easy to handle. The LX remained in production until 1997.
The LX had a hybrid electromechanical shutter with mechanical speeds between 1/2000 sec and 1/75 sec (X) and electronic speeds from 1/60 sec to 4 sec plus B. Those speeds were selectable from the speed dial, and the Automatic mode provided aperture priority.

The Integrated Direct Metering (IDM) exposure system was a full-aperture, center-weighted, through-the-lens light metering system for both automatic and manual modes. The IDM system, at the time considered the most accurate light metering system available, measured light at the film plane by means of a silicon photo diode (SPD) at the moment of exposure after the mirror flipped up. This made it unnecessary to add a special circuit to store exposure data. IDM circuitry is thus simpler and more reliable than conventional TTL systems. All IDM metering circuitry, including the metering cell, is located inside the body, not in the pentaprism, so finder changes do not affect the performance of the metering system. In TTL open-aperture metering, an SPD cell measures light transmitted through the quick-return half-mirror and reflecting off the metering mirror. The IDM system then indicates the photometric measurement in the viewfinder. In the automatic exposure mode the IDM system is switched on at the moment the front shutter curtain starts moving. As the shutter curtain moves, the IDM system makes an internal calculation of incoming light and controls movement of the rear shutter curtain for correct exposure. For automatic exposure in the TTL Auto Flash mode, the IDM system measures only light reflecting off the film plane, since the flash goes off after the shutter is fully open. The rear shutter curtain closes after the IDM system determines that enough light has reached the film and terminates the flash.

This system was also the best for long exposures, covering the range from -6.5 EV (125 sec at f1.2) to EV 20 (1/2000 sec at f22) at ISO 100 in automatic mode and in manual from EV 1 to EV 19 (at ISO 100 with f/1.4 lens).


Pentax LX Gold - In October 1981 a special limited edition of three hundred LX cameras was produced to celebrate the company's achievement of being the first manufacturer to produce ten million SLR cameras. On this version all the metal parts are gold plated. The leather covering is brown skin and the plastic parts are dark brown. The accompanying SMC Pentax 1:1.2 50mm lens is similarly finished with brown leather covering the focusing ring. The camera came with a brown ever-ready case.
Another special edition of the camera was made in the year 2000 Millennium Models (Y2K/2000 Special Edition), again with the 50 mm f/1.2 lens in a special brushed aluminum finish.

Specifications

  • Film: 35mm, speeds ISO 6 to 3200 (manual selection).
  • Lens mount: Pentax K bayonet.
  • Viewfinders : Interchangeable viewfinders; aperture visible in standard FA-1, FA-1W, FC-1, and FD-1 finders.
    • Tricolor display for TTL-measured shutter speeds, with green LEDs indicating hand-holdable speeds from 1/2000 sec to 1/30 sec, yellow LEDs as slow-speed warning from 1/15 sec to 4 sec, and red LEDs indicating overexposure or long exposure and "X"-sync flash-ready light with TTL and dedicated flash units; blue flag indicates automatic at "A" and manually selected shutter speeds.
  • Metering: TTL center-weighted (60/40), meter on film plane IDM activated by lightly pressing shutter release button, EV -6 - 20 at ISO 100, f 1.4
  • Shutter: Hybrid electromechanical horizontal titanium focal plane shutter; speeds: mechanical, 1/2000-1/75 sec and electronic, 1/60-4 sec.
  • Exposure modes:
    • A: Aperture priority
    • M: Manual by selecting the shutter speed
    • X: flash sync (1/75s)
    • B: Bulb
  • Dimensions: 144.5×90×50mm with standard FA-1 finder.
  • Weight: 565g (19.9 oz.) with standard FA-1 finder.
  • Manual film transport, single stroke of 120 degrees or multiple short strokes to cock the shutter. Lever stand-off position at 25 degrees.
    • Up to 4fps and automatic rewind with Winder LX and Motor Drive LX.
  • Battery: 2x 1.5V alkaline or AgO SR44/LR44, or 1×CR11108

Links



Pentax K mount SLR Cameras
K2 | KX | KM | K1000 | MX | ME | ME Super | ME-F | MV | MV1 | MG | LX | Super-A | Program-A | A3 | P30 | P50