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Camera Shutter speed
Shutter speed involves a mechanical switch between the lens and the
camera sensor. The switch determines the amount of time the sensor is
expose to the light.
Aperture setting determines the amount of light going into the sensor
whereas shutter speed determines how long the sensor is exposed to
light. Both the setting of aperture and shutter speed determines the
exposure of the camera sensor to the light.
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Shutter speed is expressed in seconds, usually it is expressed in:
B, 1, 2, 4, 8, 15, 30, 60, 125, 250, 500, 1000, 2000, 4000, 8000, etc
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B is referred to Bulb setting, whereby user control how long the
exposure time. During Bulb setting, when we press the shutter once, the
sensor is expose to light until we press the shutter again to close it
and it can goes as long as it is.
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For the rest of the shutter speed setting above, it is express as (1/N)
seconds, meaning the shutter speed controls are from 1s, 1/2s, 1/4s,
1/8s and so on. Notice that the exposure time actually goes twice as
fast from stage to stage, for example 1/500s is twice as fast as 1/250s
which is again twice as fast as 1/125s. Similar to aperture setting, the
different between the shutter speed is also referred as one stop; hence
1/500s is one stop faster than 1/250s.
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While aperture setting determines the depth
of field of the photos, shutter speed determines the time/moment the
photo is taken. As we try to take photo of a fast moving object, we need
faster shutter speed in order to freeze the action and capture it into
photo. On the other hand, when we want to take photo that gives an
impression of continuous movement, such as the movement of water that
looks like angels hair in
the photo, or the movement of a fast speed sports car, we need slower
shutter speed to extend the time of exposure and capture the continuous
movement.
Movement of water in slow shutter speed of seconds.
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Other than time, shutter speed also determines the stability of a photo
taken. Depending on how stable you hold the camera while taking
photographs, though generally there is certain of shutter speed that we
can safely take the photos without risking it getting blurred.
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The general rule of thumb is to shoot with the
shutter speed at least
1/focal length. For example if the focal length is 100mm, then we must
at least shoot with shutter speed of 1/100s in order to get a clear
photo, if the focal length is 300mm, then the safety zone of shutter
speed will have to be at least 1/300s. Any shutter speed slower than
that will have a high risk of getting blurred. As can be seen from here,
tele lens will generally need a much faster shutter speed in order for
the photos not to get blur.
If you still need a slower shutter speed to take the photos, then you
will need to use a tripod or lens with stabilizer options. Tripod will
allow you to take photo with long exposure time such as night scenery
shots and photos with bulb setting. Lens with stabilizer options will
enable user with a further 2~3 stops in shutter speed setting. For
example with a focal length of 100mm, the safety shutter speed setting
should be at 1/100s. One stop from the stabilizer will drop the safety
shutter speed from 1/100s to 1/50s, two stop will drop it further to
1/25s. Hence, stabilizer is a great option to have especially when
taking photo with tele lens and require slower shutter speed to achieve
sufficient exposure. Of course, lens with stabilizer option will have an
expensive pricing.
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More about
Camera Setting
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