Technical Explanation Of The Camera; Electro-Mechanical Shutter - Canon EF Instructions Manual

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TECHNICAL EXPLANATION OF THE CAMERA

The Canon EF is a 35mm single-lens-reflex AE
(automatic exposure) camera which is designed for
fast handling and precise exposure control. Being
modularly constructed, it contains many advanced
electronic circuits to make picture-taking easier than
ever before.
A

Electro-Mechanical Shutter

The vertically moving metal focal plane shutter in
the EF has speeds from 1/1000 sec. down to a full
30 seconds, plus a "B" (Bulb) setting for manual
time exposures. The shutter is electronically con-
trolled in its slow range from 1–30 sec. in six discrete
steps (1, 2, 4, 8, 15, and 30). The red Light Emitting
Diode (LED), just to the left of the pentaprism,
blinks on and off to indicate when the shutter is
open. In the normal range in which most photog-
raphy will be performed, the shutter is mechani-
cally controlled from 1/2-1/1000 sec., plus B, in
ten steps (1/2, 1/4, 1/8, 1/15, 1/30, 1/60, 1/125,
1/500, 1/1000, and B). Electronic control of the
shutter in the slow range insures high accuracy for
long shutter speeds, whereas mechanical control in
the normal range permits manual operation of the
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