How to use wide-angle lenses
Right Image: Digital SLR, Tokina ATX 20-35mm zoom, 1/4 sec at f-11 on aperture priority, Multisegment metering, Bogen Tripod and ball head.
Wide-angle lenses are much more difficult to work with than
longer focal lengths, even super telephotos. With telephoto lenses, you have less worry
about composition since only a portion of the scene is viewed through the viewfinder. Less
objects in the frame makes organizing the scene much easier. Wide-angle lenses with their
broad angle of view, include everything that is in front of the camera making it difficult
to exclude unwanted objects. You can easily become tempted to include everything,
especially if you have already set up your tripod and chosen your shooting position. First
step is to find the spot you want to shoot from and the composition. Do this without
setting up the camera on your tripod. Walk around and look through the viewfinder until
you find the best composition. Look carefully to make sure you are not including any
unwanted objects. Everything in the frame should work together without distracting the
viewer. I have shot beautiful landscapes only to see dead branches, soda cans, and even
telephone poles in the pictures that I just didn't notice when I was photographing.
Controlling depth-of-field is another problem. Some believe that wide-angle lenses have
greater depth-of-field than telephoto lenses and since wide-angles cover a wide view,
depth-of-field is not much of concern. Wide-angles have more depth-of-field than
telephotos only if shot from the same points. If you use a 24mm lens and then back off and
use a 100mm lens but cover the same image size at the same f-stop, then depth-of-field
will be the same with both lenses. Background and perspective will look different because
of angles of view, but depth-of-field will be the same. You need to pick the right f-stop
to make sure everything is in sharp focus, especially when including a strong foreground.
You will find that this is not always easy. Shoot a landscape and move-in close to include
wild flowers and the background and you'll discover that even the smallest f-stop may not
cover the depth-of-field you need. Single focal length lenses have one great advantage
over zooms. They include hyper focal distance markings on the lens. You can use hyper
focal markings to quickly find the f-stop that can bring everything into sharp focus.
Focus on a point in the scene and then refer to the markings and see the closest and
farthest points of sharp focus at different f-stops. For instance, if focusing point is at
10 feet and the scale reads depth-of-field from 5 feet to infinity at f-8, then you set
the lens to f-8 or smaller and make sure the closest foreground is at 5 feet. You can and
should use depth-of-field preview if your camera has this feature to check depth-of-field.
At times, no matter how much you stop the lens down, you can't get everything into sharp
focus. When you focus the lens, only one plane in the scene comes to sharp focus. This is
the point which is parallel to the film and cannot be changed unless you use tilt/shift
lenses or a view camera. Tilt/shift and view cameras allow movements so you can change the
plane of focus and by stopping the lens down bring everything else into sharp focus. With
normal lenses, you must take extra caution where you focus the lens and pick the right
f-stop.
Some features you need to look for when buying a wide-angle lens are close-focusing
distance, zoom or fixed focal length, and lens speed. Lens speed is not a great concern
with wide-angle lenses since you almost always stop the lens down to gain depth-of-field,
but faster models allow brighter view and are helpful in low light. Zoom lenses are not
what they seem. A 20-35mm for instance, may actually be a 21-34mm! This is also true with
longer zooms. A 75-300mm which has an actual focal length of 295mm at the longer range is
not a big problem since 5 or 10 millimeters makes not much difference in telephoto range.
With wide-angle lenses however, every millimeter counts. You should also look for a lens
with short close focusing ability. You need a lens that can cover your foreground shots.
Some zooms, especially all-in-one zooms with wide to long telephotos have far close
focusing ability. Use a lens hood at all times to reduce flare which is a big problem with
wide-angles and if you use polarizing filters, vignetting may show in the corners if you
use thick filters.