How to Buy Digital Camera Lenses
With new technology comes new opportunity. This statement is
particularly true in the case of digital cameras, and more
importantly, as the title of this article suggests, in the case
of digital camera lenses.
There are so many different lenses with varying specifications
available that it can be quite overwhelming to find exactly what
it is that you require from a lens, but that is where we step in
to help.
This article acts as a guide to explain the jargon and to allow
you make a better-informed purchase the next time you are
shopping for a new digital camera lens.
Choosing a Suitable Focal Length
Focal length is
probably the most important factor that should be considered
when choosing a lens, and for good reason: focal lengths
determine the field-of-view of the photos you will be able to
take successfully with your camera.
The two main types of focal length are telephoto and wide-angle,
and while telephoto lenses have a narrow field-of-view and are
best suited for close-up shots and portraits, wide-angle lenses
have a wider field-of-view which is perfect for indoor
photography and landscapes.
Keep in mind that the performance of lenses can differ from
camera to camera, with the magnification power behind a lens
generally being greater on a digital camera than on a 35mm
film-based camera.
The Need For Speed
When you hear about fast and
slow lenses, reference is being made to a lens's maximum
aperture, which is the maximum amount of light that a lens can
let in. A simple rule of thumb is that a fast lens lets in a lot
of light, while a slow lens lets in less light, which defines
how your photos will look.
Maximum apertures are measured in f/stop numbers, which are
actually a ratio of the size of the lens aperture and focal
length. The smaller the f/number, the more light is let in. An
increment in the f/stop number doubles the amount of light let
in, so f/2.0 lets in twice as much light as f/1.4.
This may seem quite confusing at first, so the easiest way to
make sense of it is to remember the following: fast lenses are
best suited towards successful photography in darker lighting
conditions, and slow lenses are targeted towards photography in
lighter conditions.
The Ins and Outs of a Zoom Lens
Unlike a
fixed-focal-length lens, a zoom lens often gives you the
diversity of a range of focal lengths all rolled into a single
adjustable lens. This can be great if you often have to switch
between various lenses for different shots, but it is important
to remember that not all zoom lenses have a constant maximum
aperture, and those that do are often larger and more expensive.
Although the maximum aperture may be reduced as you zoom in
using a lens with a variable maximum aperture, this may not be
as important to some photographers as the reduced cost and size
of such lenses. Keep this in mind when purchasing a zoom lens.
Add-on Lenses
Add-on or accessory lenses are
targeted towards compact digital cameras, and allow owners of
such models to significantly lengthen or reduce the camera's
built-in focal length while at the same time being able to
automate camera functions including f/stop settings and focusing.
These lenses can be an excellent low-cost add-on to your digital
camera, with telephoto add-on lenses being able to increase
focal lengths by up to 300%, and wide-angle versions allowing
for reduction in focal lengths of up to 30%.
Final Considerations
There are several other
terms to take into consideration when buying a digital camera
lens to make sure you are making the best purchase. If your lens
utilizes aspheric lens elements, then you can rest happily with
the knowledge that your lens will help produce sharper
photographs and help keep lens weight to a minimum.
Lenses using internal and automatic focusing also keep lens
weight down thanks to less moving parts, and of course allow for
faster focusing. Low-dispersion glass leaves photos looking less
hazy or fuzzy, while stabilization systems help to keep images
sharp when taken using slow shutter speeds.
Conclusion
Hopefully this article has helped you
to better understand what to look for in a digital camera lens.
There are a lot of terms to remember here - so before shopping
for your new lens it may be a good idea to take the time to make
a list of what you want to do with your camera. Then you can
double check your requirements against the features of different
lenses. If you are still unsure if a lens will cater for your
needs then by all means try to test it so that you can see some
results before you buy!