Canon A-1 Repair Manual page 18

*.
•
maximum aperture before resetting it to the
"A" mark.
The information (a), (b), (c), and (e) is display-
ed in seven segment LED's and (d) in a five-digital-
segment LEO*.
Numerals shown in 1/2 step increments are not
always strictly exact ones and may be rounded off
to familiar ones.
(Example)
An
intermediate value between f/2 and f/2.8 is
f/2.38 but it is displayed as f/2.5 (differ-
ence is 0.15 f/stops).
o Shutter speeds longer than 1 sec. are displayed
with the second(") mark.
(Example)
1/15 sec. is displayed as
15 sec. is displayed as
o Exposure is, as a matter of fact, controlled in
1/8 step increments. However, it would be trouble-
some to have these values display in the viewfinder
as they would change so quickly depending on light-
ing conditions. Because it would be hardly possible
to see a continuously changing shutter speed and
aperture readout which are unfamiliar to users,
we have done much testings about viewfinder infor-
mation. After considering the physiological
characteristics of human eyes, we have arrived
at the conclusion that the signals of exposure
should be transmitted to the display in 1/2 step
increments.
This is why the A-l's viewfinder displays shutter
speed and aperture values in 1/2 step increments
as indicated below.
The M has five segments itself.
the aperture is electrically one
The decimal pOint in
segment of the M digit.