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Lenses [And The Landscape]
Film Vs. Digital | Zooms | Wide-Angles | Telephotos | Zooms Vs. Fixed
By Ibarionex R. Perello |
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Painters have many options
when creating on the canvas. They have a wide selection of brushes,
oils and colors from which to choose when painting a landscape. Photographers
are no different. Although we’re not choosing between types
of camel-hair brushes, we’re offered a wealth of alternatives
when it comes to lenses and focal lengths. What we decide on can make
all the difference in the world.
It’s easy to just pick the widest lens in our bag and shoot
landscapes, but that won’t guarantee a successful shot. Instead,
it’s important to consider the strengths and weaknesses of a
variety of focal lengths before committing. Even if you’re using
a zoom lens, you should carefully consider what focal length will
best capture those telling elements of a scene.
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![Lenses [And The Landscape]](images/lenses.jpg) |
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[ Film Vs. Digital ]
Although the information in this article is applicable to both digital
and film cameras, focal lengths will be related to the 35mm format.
Because most image sensors are smaller than 35mm, the actual focal
length may have little relation to what you expect based on 35mm.
The way a lens/sensor combination responds to a scene is totally dependent
on the size of the sensor. The result usually is subject to magnification
within the image frame. For example, a 100mm lens attached to a digital
SLR with a 1.5x magnification factor performs as a 150mm lens would
on 35mm. We’ll use the convention of 35mm focal lengths for
reference here, so compare lenses with your camera by using 35mm equivalents.
[ Zoom Lenses ]
Zoom lenses have usurped fixed focal lengths as the lens of choice
for all aspects of photography, including landscape. Their optical
quality often rivals those of prime lenses with the added convenience
of multiple focal lengths within a single lens. What makes these lenses
so much better than they were 20 or more years ago? Well, computer-aided
design and the use of aspherical and low-dispersion elements have
gone a long way to producing high-quality optics.
Aspherical lenses are specially shaped elements that correct for a
variety of optical and color aberrations that occur within an optical
design. To create consistent optical quality throughout a zoom range,
lenses use one or more aspherical elements to correct spherical aberrations
(pincushioning and barrel distortion) as well as improve contrast
and sharpness. Aspherical elements reduce the need for multiple glass
elements, thereby creating a smaller and more compact lens.
An increasing number of lenses— fast-aperture, telephotos and
ultra-wides—also are incorporating low-dispersion elements in
their design. These elements correct for chromatic aberrations, which
can lead to decreased color accuracy, particularly toward the edge
of the frame. You’ve seen dispersion when viewing light through
a prism, which is dispersed into its component light waves, creating
a fan or spectrum of color. Although pretty to look it, it’s
bad news when you’re trying to photograph a scene. The use of
low-dispersion elements ensures that the path the light travels through
the lens remains concentrated and stable, guaranteeing color accuracy
and image brilliance.
[ Wide-Angles ]
Wide-angle lenses always have played a big role in landscape photography.
Lenses like the 24mm and 28mm have been a staple for a long time.
Although wider lenses were used, they often were prohibitively expensive
for anyone other than the professional photographer. Now, lenses as
wide as 14mm or more are available at a more accessible price point.
These lenses not only provide a wider angle of view, but are a dynamic,
creative option.
The wider the focal length, the greater the field of view. For example,
a 28mm lens gives you an angle of view of 74 degrees. Attach an 18mm
lens to your camera and the field of view increases to 100 degrees.
If you’re unable to move farther back to capture more of the
scene, a wider lens can deliver the increased angle of view you need.
Some prime wide-angle lenses are designed to be rectilinear, which
means that straight lines remain straight when shot with such a lens.
Extreme wide-angle lenses, even as wide as 14mm, can afford an ample
field of view with rectilinear performance.
Specialty lenses also are available as prime lenses. With a field
of view of 180 degrees or more, fish-eye optics offer an unusual way
of looking at the world. Traditional fish-eye lenses created a circular
image within the rectangular frame. Now there are full-frame fish-eyes
that provide the same angle of coverage, but utilize the full rectangular
frame. Unlike rectilinear lenses, curvature will be evident toward
the edge of the frame, though you’ll have a much greater angle
of view.
As well as allowing increased coverage, wide focal lengths offer greater
depth of field, which results in objects in an image appearing sharp
despite being far apart. You can compose a distant mountain range
with a strong foreground object and keep both in focus, for instance.
Such a composition creates a dynamic counterpoint to the background
and results in a greater sense of depth and perspective.
Perspective can change dramatically with wide-angle lenses by simply
changing where you position the camera. Imagine you have large rocks
in the foreground of a landscape. By switching to a wider lens and
remaining in the same position, the rocks become less prominent objects
in the photograph. If you want to emphasize them for the sake of composition,
lower the camera and move closer to the formation, thereby increasing
the apparent size of the rocks in relation to their surroundings.
This change in perspective can produce a much more successful image.
Because so much of the scene is captured by such lenses, it’s
easy to include too much in the photograph. With this all-encompassing
range, an image can have so many details that the viewer is unable
to focus on any central point.
Rather than simply getting in as much as you can within the frame,
consider traditional compositional elements, such as leading lines,
contrasting textures, highlights and shadows, to draw attention to
the most important parts of your scene. Although this is applicable
to any focal length, it can be particularly important when using extreme
wide-angle lenses.
[ Telephotos ]
Telephoto lenses bring distant objects closer. Moderate telephotos,
ranging from 85mm to 200mm, and super-telephotos of 300mm and longer,
have a narrow field of view that creates an emphasis on individual
details that otherwise might be lost with a wider focal length.
Another inherent quality of the telephoto lens is an optical effect
called compression. Compression gives the impression that objects
appear closer to each other than they actually are. This effect creates
a sense of proximity between distant objects that can serve as a means
of contrasting elements in a scene. You could isolate a stand of trees
against a distant mountain range and create a sense of scale, for
example.
Compression can be useful for capturing a variety of textures or patterns
that exist in a scene. In a photograph taken in the desert, for example,
the frame can consist of a pristine foreground of sand, the undulating
rise and fall of the dunes and the rising mountain ranges in the background.
These elements are compressed and isolated by the telephoto lens,
resulting in an image where the different textures and shapes serve
as contrasting elements in the final photograph.
Compression also can be used effectively with contrasting tones in
an image. If a scene includes a group of white aspens in front of
a darker stand of trees, the proximity created by the telephoto lens
boosts the difference in color and tone, producing a shot with significantly
more impact than might be achieved with a wider focal length in the
same camera position.
By knowing your lenses when composing landscape images, you’ll
have what you need to create a piece of art rather than a snapshot.
[ Zoom Vs. Fixed Lenses ]
It used to be that fixed focal-length or prime lenses were considered
far superior to zooms. That’s no longer the case. Many
zoom lenses offer optical quality comparable, if not superior
in some cases, to their prime siblings. So why choose a fixed
focal length over a zoom? There are several reasons.
The first one is speed—not how fast the
lens can focus, but rather the lens’ maximum aperture.
Many fixed focal-length lenses offer a maximum aperture of ƒ/2.8
or ƒ/4. For example, a fixed 300mm ƒ/4 lens will provide
a full stop of light more than a 100-300mm ƒ/3.5-5.6, which
has an effective aperture of ƒ/5.6 at its 300mm setting.
Hence, the lens gathers more light for a brighter image in the
viewfinder and maintains an exposure with a higher shutter speed
under low light conditions. In addition, because more light
is coming through the lens and reaching the AF sensor, the camera
has a better chance of quickly achieving autofocus.
Variable-aperture zoom lenses transmit less
light whenever you create its telephoto range. For example,
a 24-120mm ƒ/3.5-4.5 lens starts off with a relatively
wide aperture, but by the time it reaches its 120mm focal length,
you’ve lost almost a full stop of light. This means that
if you were shooting at a shutter speed of 1⁄30 sec.,
you’d have to decrease the shutter speed to 1⁄15
sec. to maintain the same exposure. You’d likely end up
with a soft image because of camera motion or even shutter vibration.
There are zoom lenses with a constant aperture, but generally they’re considerably more expensive than
their variable-aperture versions. If you can afford them, they’re
a worthwhile investment, especially since you’re shooting
during dusk and dawn in most landscape photography.
Fixed focal-length lenses also are subject
to less spherical aberration, such as pincushioning and barrel
distortion. Appearing as bowing toward the edges of the frame,
these distortions usually are evident with wide-angle zoom focal
lengths, where straight lines are slightly curved inward (pincushion)
or outward (barrel). Although highly corrected, some zooms do
better than others in this respect.
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