Canon F1-N 用户手册
12
APERTURE
Blurring part of the picture can heighten the sense of action. In most cases, how-
ever, image blur is undesirable. To avoid blurred pictures from camera movement,
choose a shutter speed of at least 1/60 sec. for handheld shooting with a standard
lens.
With a telephoto lens, it is advisable to use faster shutter speeds. The rule of thumb
is to use a shutter speed no slower than the reciprocal of the lens in use. This means
that for a 100mm lens, the shutter speed should be at least 1/125 sec.; for a 500mm
lens, it should be at least 1/500 sec.
ever, image blur is undesirable. To avoid blurred pictures from camera movement,
choose a shutter speed of at least 1/60 sec. for handheld shooting with a standard
lens.
With a telephoto lens, it is advisable to use faster shutter speeds. The rule of thumb
is to use a shutter speed no slower than the reciprocal of the lens in use. This means
that for a 100mm lens, the shutter speed should be at least 1/125 sec.; for a 500mm
lens, it should be at least 1/500 sec.
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Aperture
The size of the aperture determines the amount of light allowed to reach the film.
The apertures are indicated by a series of numbers, called f/stops or f-numbers,
iV‘hich can be found on the aperture ring. The smaller numbers are called large
f/stops while the larger numbers are called small f/stops. This is because the smaller
numbers represent larger apertures which allow more light to pass through the lens.
The largest f/stop on the lens is called the lens maximum aperture; the smallest
f/stop the lens minimum aperture. The maximum and minimum apertures differ
depending on the lens.
Each time you turn the aperture ring from one f/stop to the next smaller one,
the amount of light allowed through is exactly halved. Using f/2 as a standard, the
amount of light striking the film will change according to the f/stop indicated below.
The apertures are indicated by a series of numbers, called f/stops or f-numbers,
iV‘hich can be found on the aperture ring. The smaller numbers are called large
f/stops while the larger numbers are called small f/stops. This is because the smaller
numbers represent larger apertures which allow more light to pass through the lens.
The largest f/stop on the lens is called the lens maximum aperture; the smallest
f/stop the lens minimum aperture. The maximum and minimum apertures differ
depending on the lens.
Each time you turn the aperture ring from one f/stop to the next smaller one,
the amount of light allowed through is exactly halved. Using f/2 as a standard, the
amount of light striking the film will change according to the f/stop indicated below.
How the Aperture Affects the Picture
In addition to controlling the quantity of light, the aperture influences depth of field
which, in turn, affects the way a picture will look. When your subject is in focus,
there is a certain area in front of and behind it which will also be in focus. This
range of sharpness is called depth of field.
In addition to controlling the quantity of light, the aperture influences depth of field
which, in turn, affects the way a picture will look. When your subject is in focus,
there is a certain area in front of and behind it which will also be in focus. This
range of sharpness is called depth of field.
f/stop
(1.2)
1.4
(1.8)
2
2.8
4
5.6
8
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Brightness ratio
3
2
1-1/4
1
1/2
1/4
1/8
1/16
1/32
f/stop
16
22
32
Brightness ratio
1/64
1/128
1/256
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