Pentax LX LX Manual - Page 27

METER COUPLING RANGE 2505 1250 64S 32S 160 8 4S 2S 1 1/ 2 1/4 1/8 1/15 1/30 1/60 1/125 1/250 1/500 1/1000 1/2000 ---- 1 1.4 2 Manual Exposure Coupling Range 42.8 L Automatic Exposure Coupling Range --- c0 n 5.6 s 11 16 22 ASA/ISO14 6 12 25 • 50 100 200 400 800 1600 ,41 g g 3200 The I DM (Integrated Direct Metering) system of your Pentax LX assures superbly accurate exposure readings over a broad range of shutter speed/film speed combinations. The working EV range of the IDM metering system for both manual and automatic exposures is reflected in the reference chart above. With ASA/ISO 100 film at f11.4, for example, the manual coupling range extends from EV 1 (1 sec. at f/1.4, 2 sec. at f/2) through EV 19 (1/2000th sec. at f/16, 1/1000th sec. at f/22). In the automatic mode with ASA/ISO 100 film and an f/1.2 lens, it extends all the way from EV -6.5 through EV 20 (125 sec. at f/1.2 - 1/2000th sec. at f/22 under normal temperatures and humidity). Although the meter coupling ranges for the respective manual and automatic exposure modes change in relation to film speed, you can calculate what the working EV range would be at other film speeds by mentally adjusting the position of the frame of the chart which defines the coupling range for the mode in question. The red frame defines the manual meter coupling range and moves vertically along the righthand film speed index; the grey frame defines the lower limits of the coupling range for automatic exposures and moves horizontally along the left-hand film speed index. The boundaries of the red frame should be disregarded when determining the coupling range for automatic exposures; at the higher end of the. EV scale, meter coupling is provided for all available film-speed/shutter-speed/f-stop combinations during automatic exposure operation. 25*