H ki ki kis – Canon A-1 User Manual
Page 55
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through the lens. Each time you move from
one f/stop to the next smaller f/stop (larger
number),
the
amount
of
light
allowed
through
is
exactly
halved. In effect,
the
amount of exposure itself is also halved.
Using f/2 as a standard, the amount of light
reaching the film will change according to
f/stop as indicated below.
On
the
A-1,
aperture
can
be
controlled
either by turning the AT dial or the lens
aperture ring to the desired f/stop. Other
wise the camera controls the aperture.
The largest f/stop on the lens is called the
lens maximum aperture. The smallest f/stop
on the lens is called the lens minimum
aperture.
The
maximum
and
minimum
apertures
differ
according
to
the
lens.
The
maximum
lens
aperture
is
important
because it indicates the largest amount of
light that the lens will transmit.
f/stop
1 2
1 . 4
2 . 8
3 , 5
4
5 . 6
8
11
16 22
Brightness ratio
H ki
ki kis
-31-