Pentax LX Quick Help/Reference Manual page 10

IMPORTANT. Should you accidentally press the shutter release with the lens cap on or in the dark while the shutter dial is set to "Automatic," an
excessively long exposure will result. To re-set the camera, move the dial to one of the manual speed settings and return it to the "Automatic" position
before resuming shooting.
USING THE EXPOSURE COMPENSATION DIAL
Although the center-weighting of your LX camera's metering system is designed to provide accurate exposure measurement under the majority of lighting
conditions, when using the camera in the automatic mode you may find that a degree of exposure adjustment is desirable. This is particularly true in scenes
with extremely contrasty backgrounds or foregrounds, or where special creative effects can enhance the overall quality of the photograph. The exposure
compensation dial allows you to make these adjustments quickly and easily.
ALWAYS SET THE EXPOSURE COMPENSATION DIAL BACK TO THE 1X POSITION BEFORE RETURNING TO NORMAL AUTOMATIC
OPERATION.
The dial, located beneath the film rewind knob, permits you to override the automatic exposure setting by a full +2 EV (i.e., two full f/stops over or
underexposure) in 1/3 increments. The dial is in. dexed at 4X (2 f/stops increase), 2X (one f/stop increase), 1/4X (2 f/stops decrease' and 1/2X (one f/
stop decrease) with click stops at each 1/3 increment.
Normal Position: For normal automatic exposure control, make sure the dial is set to the "1X" position. The Dial locks firmly in this position to prevent
accidental movement.
When the dial is off the "1X" index, a red flag will appear in the upper right-hand side of the camera viewfinder as a reminder.
A red LED will glow next to the "A" index on the viewfinder scale to indicate
overexposure. When this occurs, stop your lens down or change to manual exposure
control to obtain acceptable exposures.
A red LED will glow next to the "LT, B" index on the scale when there is insufficient
light for a proper exposure or when the camera has selected a time exposure longer than
4 seconds in the automatic mode.
Green LEDs are used along the shutter speed scale between 1 /2000th and 1 /30th
second to indicate hand-holdable speeds.
Yellow LEDs are used along the shutter speed scale between 1/1 5th second and 4
seconds as a slow speed warning and reminder to use a tripod or supplemental lighting,
or to change the lens to a wider aperture setting.