Shutter Speeds
It is very important to be aware of the shutter speed you are
using when you take an image. In general, the way to get the sharpest
images is to have your camera on a tripod and take photographs
of objects that are not moving. However, this is not always possible.
If your camera is hand-held, then you should try to achieve the
fastest shutter speed possible to avoid blur in the images. The
amount of blur increases with longer shutter speeds. The amount
of blur also increases as the focal length of the of the lens
is increased. Some people advocate that you should have a shutter
speed greater than the focal length, so for a 50 mm lens you should
have a shutter of speed of no less that about 1/60 second. However,
if you enlarge an image taken at this low shutter speed you will
usually clearly be able to notice blur.
Most blur arises due to camera-shake, which is inevitable when
you hand-hold a camera to shoot. So, if possible, particularly
when there is lots of available light, you should use the fastest
shutter speed possible.
These days cameras have a range of speeds, from about 1/2000
s or shorter through to 15 s or longer. As well, if you want to
use a longer time, most cameras have a B or bulb setting where
you can make the shutter stay open for any extended time you choose.
These extended times are useful for such things as taking images
of stars. Even though the stars move slowly and you use a tripod,
you can see the shapes of the stars are a little elongated because
of the passage of time.
I prefer images that have the greatest depth of field possible
which means that I use the smallest aperature possible. This in
turn means that I have to use longer shutter speeds. So there
is sometimes there is a trade-off, and compromises must be made.
A good tripod is very useful to help take photographs that are
as sharp as possible. If you need to attach the camera to the tripod
and remove it quickly, then a quick-release attached to the tripod
and camera will let you achieve this with a minimum of fuss.
