Tips on Digital Photography
Get the most out of your digital camera with the following tips on digital photography
Composition and zooms
Zoom lenses allow you to change the magnification of an image without swapping lenses.
Zooms are designed to change the field of view of the lens while keeping the image
in focus. When the field of view is widened (to take in more of the subject), the
image must be reduced in order to fill the sensor area. This is the effect of using
a short focal length lens or a wide-angle setting on a zoom. Conversely, when the
field of view is narrowed (to take in less of the subject), the image must be magnified,
again in order to fill the sensor or film area. This is the effect of using a long
focal length lens or a zoom’s telephoto setting.
Working with zooms
The best way to use a zoom is to set it to the focal length you feel will produce
the approximate effect you are aiming for. This method of working encourages you
to think about the scene before ever raising the camera to your eye to compose the
shot. It also makes you think ahead of the picture-taking process, rather than zooming
in and out of a scene searching for any setting that seems to work. This is not
only rather aimless, it is also time-consuming and can lead to missed photographic
opportunities.
A professional approach
Many professional photographers use zooms almost as if they were fixed focal length,
or prime, lenses, leaving them set to a favourite focal length most of the time.
They then use the zoom control only to make fine adjustments to the framing. Zooms
really are at their best when used like this — cutting out or taking in a little
more of a scene. With a prime lens, you have to move the camera backward or forward
to achieve the same effect. Depending on the type of subject you are trying to record,
you could leave the zoom toward the wide-angle or telephoto end of its range. On
some digital cameras, however, zooms are stepped rather than continuously variable,
and so cannot be used for making small adjustments.
Zooms for framing
Zoom lenses come into their own when you find it difficult or time-consuming to
change your camera position, as they allow you to introduce variety into what mould
otherwise be similarly framed images.
Digital zooms
The term given to a computer-generated increase in apparent focal length is “digital
zoom’. Although the lens focal length does not increase, the image continues to
be magnified. It works by taking a central portion of an image and enlarging it
to fill the format, using a process called “interpolation” — extra pixels are added,
based on the existing one, to pad out the space. This does not add information;
indeed, it may even mask it. Clearly you can obtain exactly the same effect — sometimes
even superior effects — by altering the picture using image-manipulation software,
and this is very often a better option.
Long focal length
Long focal length settings on a zoom lens come into their own when you want to magnify
a small part of a scene: a 35efl of 135 mm is ample for most purposes. This produces
the characteristic “telephoto perspective’ in which distant objects look compressed,
or backgrounds in close-up shots are thrown strongly out of focus. Nonetheless,
many digital cameras now offer the equivalent of focal lengths of 300 mm and more.
Some models reduce the effects of camera shake by using image-stabilization technology.
Even so, it is worthwhile making every effort to reduce unwanted camera-movement
problems at source.
We hope you’ve enjoyed these Tips on Digital Photography. Why not try one of our
other Photography Tips article. Check the menu down the left of this page.