Slow Shutter Speeds and
Long Exposure
Photography
By: Rick Blythe
Many
new cameras will come with built-in shutter speeds
of up to 30 seconds or longer, which is enough for
most long-exposure photography. Other cameras will
have a B (bulb) setting that will keep the shutter
open as long as you keep your finger on the shutter
release button or a T (time) exposure setting that
will keep the shutter open until you press the
shutter release button a second time. Cameras with
bulb settings can also be fitted with a locking
cable release so that it isn't necessary to keep
your finger on the shutter for long exposures. If
your camera doesn't have a cable release, you can
use the self-timer option found on most cameras.
This will eliminate camera vibration from your
hands.
A tripod, or something to rest your camera on, is
essential because the camera must be completely
still during the time that the shutter is open. If
you want to make a fast-moving car blur as it speeds
by you, a relatively fast shutter speed of 1/20 of a
second may give you the results you are after,
however, if you want to make stars in the nighttime
sky look like glowing rings as the earth rotates,
your exposure may last all night.
The
light meter on your camera may not be able to
accurately judge the best aperture setting for
longer shutter speeds, especially in low-light
situations, so your best bet is probably to
"bracket." This means taking up to six pictures of
the same subject, but doubling the shutter speed
each time. This will give you a variety of effects
and exposures and allow you to choose the best shot.
In general, slow shutter speeds will allow a lot of
light into the camera, which means that you will
want to use a small aperture (ie. f/22) to avoid
over-exposing the shot. In bright daylight it will
be necessary to use the lowest ISO available and a
neutral density filter to cut the light down.
Some great effects and shutter speeds to try are:
Moving stars: several hours Moving cars at night:
10 seconds Waterfalls: 4 seconds + Amusement park
rides: 1 second
About the Author
Rick Blythe runs
Camera-News.com,
a site about digital cameras and photography.
Many
new cameras will come with built-in shutter speeds
of up to 30 seconds or longer, which is enough for
most long-exposure photography. Other cameras will
have a B (bulb) setting that will keep the shutter
open as long as you keep your finger on the shutter
release button or a T (time) exposure setting that
will keep the shutter open until you press the
shutter release button a second time. Cameras with
bulb settings can also be fitted with a locking
cable release so that it isn't necessary to keep
your finger on the shutter for long exposures. If
your camera doesn't have a cable release, you can
use the self-timer option found on most cameras.
This will eliminate camera vibration from your
hands.
The
light meter on your camera may not be able to
accurately judge the best aperture setting for
longer shutter speeds, especially in low-light
situations, so your best bet is probably to
"bracket." This means taking up to six pictures of
the same subject, but doubling the shutter speed
each time. This will give you a variety of effects
and exposures and allow you to choose the best shot.
In general, slow shutter speeds will allow a lot of
light into the camera, which means that you will
want to use a small aperture (ie. f/22) to avoid
over-exposing the shot. In bright daylight it will
be necessary to use the lowest ISO available and a
neutral density filter to cut the light down.
