The stock in trade of the wildlife photographer is the telephoto lens. Most animals are
small and get spooked when humans are near. A high-magnification lens from a long distance (i.e. a telephoto lens) is often the tool of choice for
both practical and ethical reasons. One of the prime concerns for the wildlife
photographer should be to minimize any disturbance of the wildlife you are photographing
and shooting from further away with a longer lens is one way to do this.
For photographers shooting 35mm film (or 35mm full frame digital), lenses in the
300-600mm range are most often employed. Single focal length (prime) lenses yield the
highest quality, but unfortunately range in price from around $1,000 for a 300mm f/4 lens to
over $7,000 for a 600mm f/4. There used to be several quite good 400mm f/5.6 and 300 f/4 lenses
available at affordable prices from 3rd party lens makers, but in recent years they have
all been discontinued and the only real choices below $1,000 are now telephoto zooms.
While zooms are certainly more convenient, image quality at the long end of their
range typically isn't quite up to that of primes.
Zoom lenses suitable for wildlife photography start with 70/75-300mm zooms, usually f/5.6
at 300mm, which are available from most camera manufacturers as well as most third-party
lens makers. They represent good value, but for wildlife work are often used at their
longest focal length where their optical performance is weakest. Nevertheless they are
often a good choice for someone just getting into wildlife photography on a limited
budget. Prices range from a low of about $150 up to around $650. As in most things, the
more you pay the better the quality!
There are also a number of longer zooms, such as the Sigma 50-500mm f/4-6.3, Tamron 200-500mm f/5-6.3 Di,
Canon EF 100-400mm f/4.5-5.6L IS, and ">Nikon 80-400VR, ranging in price from around $800 to around $1500.
Mirror lenses are often seen as a low-cost alternative to the more common refractive
lenses. A 500mm f8 mirror lens can be found for less than $100 for a used, third-party lens to around $500 for a new name-brand model. They are much
smaller and lighter than refractive lenses, but they have two disadvantages: First, at f/8
they are pretty slow and most of them are actually closer to f/9 or f/10 with regard to
light transmission ("T-stop"). This can make them difficult to focus manually
and the only AF mirror lens that I know of is the one that was made by Minolta. The second
disadvantage is that out of focus highlights are rendered as donuts" due to the
central obstruction of the lens. Even out of focus areas without highlights often take on
a "mottled" appearance which most people regard as unattractive.
Of course, you can do wildlife photography with almost any lens as long as you're not
trying to get frame filling shots of a single bird or animal. With any lens you can take
"environmental" shots which show the interaction of the subject with its
environment (see the image below) and with a macro lens, or any lens with a close-up
diopter and/or extension tubes you can do macro work with insects. You can also chose to
work with animals under controlled conditions, such as in a zoo where a 200mm or 300mm
lens is often long enough for closeups.
The Digital Advantage
The advent of digital SLRs has made life easier for the wildlife photographer in
several ways.
First, sensors with an area smaller than that of 35mm have resulted in the so-called "Lens Multiplier" factor--cropping the image which would be recorded on 35mm film using the same lens. The resulting smaller angle of view is given an equivalent to the use of a lens with a longer focal
length.
Let's take the Canon EOS 30D as an example. Its "lens
multiplier" factor is 1.6x, which means a 300mm lens used on them gives the same field of
view (or magnification) as a 480mm lens would using 35mm film. Of
course the "multiplier" is just the result of cropping, and you could crop 35mm
film. However the fact is that the quality of an 8MP or more APS-DSLR image is better than
that of a scanned 35mm negative of slide cropped to the same size.
Obviously, you can't
take this too far. If you used an even smaller sensor to give you, say, a 3x multiplier,
to get 8MPor more the pixels would have to be much smaller (leading to higher noise
levels) and other optical factors would come into play that would degrade image quality.
Before the days of APS-C DSLRs, a 300mm f/4 lens was regarded as a very good
"starter" quality telephoto prime (in other words, a non-zoom lens), and a 500mm f/4 was the dream lens of many
amateur nature shooters. With the 1.6x multiplier of cameras like the EOS 30D, that 300mm
f/4 becomes very nearly the equal of that dream 500mm f4 (480mm, to be precise).
For a wildlife photographer, though, no lens is ever really long enough, so most still lust after a
500mm f/4...which now works like an 800mm f/4 on a 35mm film camera--a lens which
would have been so large, heavy and expensive that almost nobody could ever have afforded
it or wanted to carry it around in the field. This is an obvious advantage for wildlife
photography where getting close enough to your subject with a long enough lens is often
the primary task.
The "digital multiplier" also means that 70-200mm lenses can be pressed into
wildlife service since on a DSLR like a Canon EOS 30D they're equivalent to a 112-320mm
zoom.
Another advantage of digital cameras is that ISO can be changed at any time, and
excellent quality is available at ISO 800 and even ISO 1600. When I was actively shooting
wildlife on film, I remember carrying multiple camera bodies loaded with ISO 50, ISO 100
and ISO 400 in order to cope with changing light.
With a DSLR you can just dial in a
different ISO for every shot, enabling a photographer to cope with rapidly changing light
or shoot from midday to after sunset with just one camera body. Many wildlife species are
most active at dawn and dusk (when the light level is low) and the lighting is often at
it's best at those times, so high ISO capability can be very useful.
Image Stabilization
Image-stabilized lenses enable a photographer to shoot at shutter speeds up to about 3
stops slower than would normally be possible. They do this by sensing lens movement using
gyroscopic sensors and using the signals to control a lens group which keeps the image at
the same place on the film or sensor.
It's an approximate rule of thumb that most
photographers can handhold a 35mm camera and lens at a shutter speed equal of (1/focal
length) seconds, so for a 100mm lens it would be 1/100 second and for a 500mm lens it would be
1/500 second. APS-C format DSLRs require faster shutter speeds by the same factor as the lens
multiplier, so a 100mm lens on a APS-C DSLR has the field of view a 160mm lens would have
on a full frame 35mm SLR and requires a shutter speed of 1/160 second or faster.
Similarly, a
500mm lens on an APS-C DSLR would require a shutter speed of 1/800 second or faster for sharp
hand held shots. These numbers are approximate of course. Some photographers with steady
hands might be OK with slower shutter speeds and those on their 10th cup of coffee of the
day might require faster shutter speeds!
Some lenses have dual stabilization modes, one which stabilizes in both the horizontal
and vertical axes for shooting static subjects and one which only stabilizes in the
vertical axis which allows horizontal panning. The in flight shot of an Osprey shown below
was taken using a hand held Canon EF 70-300/4-5.6 image stabilized lens at the 300mm focal
length setting using the horizontal panning mode.
No tripod is perfect and even with a very sturdy support a long lens may be buffeted
and shaken by wind, so image stabilization of long telephoto lens can be valuable even
though you'll likely never try to hand hold them for a shot.
Canon has the largest lineup of image stabilized (IS) lenses, from a 600mm f/4L IS USM prime lens to a
Canon EF 70-300mm f/4-5.6 IS USM zoom, but Nikon (VR - Vibration Reduction) and Sigma (OS - Optical
Stabilization) also have optically stabilized lenses. Sony, Konica Minolta (which has sold its assets to Sony and is no longer in the camera business) and Pentax have DSLRs
with an image stabilization system built into the camera, which accomplishes much the same
thing but might be a little less effective with longer lenses.
Multipliers (Tele-converters)
Multipliers (also known as TCs or tele-converters) are commonly used to increase the
focal length of a lens. They are available in versions which multiply the focal length by
1.4x and 2x. The 1.4x version reduces the resulting lens aperture by one stop, so, for
example a 300mm f/4 lens would become a 420mm f/5.6 lens when a 1.4x multiplier is added. A
2x multiplier results in a two-stop loss, so the same 300mm f/4 lens would become a 600mm
f/8.
Besides the speed penalty, there is also a loss in optical quality. With really good
prime lenses and a high quality 1.4x multiplier the loss in quality is often negligible.
With a 2x multiplier quality loss is greater, but the image can still be good when the
original lens and multiplier are excellent. Autofocus may also be affected and may not
operate if the speed of the final lens combination drops below f/5.6 (f/8 for some cameras).
Though many beginners are tempted to add multipliers to zoom lenses, they tend not to
work so well. So although your 75-300 zoom could be converted into a 150-600mm zoom by the
addition of a 2x multiplier, critical photographers would be unlikely to be happy with the
results.
In some systems, such as the Canon EOS system, the manufacturer's multipliers will
only fit a small selection of lenses, usually telephoto primes and maybe telephoto zooms.
They won't even physically mount on consumer zooms. Third-party manufacturers do make
multipliers which will fit on any lens but quality may be slightly lower and some can
result in mild vignetting due to the use of smaller diameter optics.
Lens and Camera Support
The longer the lens and the higher the magnification it produces, the more stable the
camera has to be to obtain sharp images. A sturdy tripod is
essential. It would make little sense to
spend $5,000 on a 500mm f/4 telephoto lens and then mount it on a wobbly tripod.
Sturdy
tripods tend to be heavy, but today the use of exotic materials like carbon fiber can
result in sturdy tripods which weigh considerably less than aluminum
tripods. That they are typically at least twice as expensive, but it's an investment many nature photographers are prepared to
make. When you are carrying your lens and tripod a few miles through the woods, extra
weight is the last thing you want. Gitzo, Bogen-Manfrotto, Slik, and Velbon make good
carbon fiber and aluminum tripods.
Most wildlife photographers use a ballhead on their tripod rather than a three-way
pan/tilt/rotate head. With a ball head one control locks the whole assembly and when not
locked the lens can be moved in any direction to track moving animals. A very popular head
with serious wildlife photographers is the Arca-Swiss B1. Not cheap, but quality rarely
is. Acratech also makes excellent ball heads at a slightly lower price and
Bogen-Manfrotto has a line of fairly inexpensive ball heads that are an excellent value.
Digiscoping
Digiscoping is a technique popular with birders. You use a small digital camera to
shoot though the eyepiece of a spotting scope. It can give a very high degree of
magnification for a relatively low cost, so birders don't need to
carry both a spotting scope and a telephoto lens.
The disadvantage is that image quality
isn't as good as when using a DSLR telephoto lens and the system is often optically pretty
slow which means the use of high ISO settings or low shutter speeds. High ISO settings
mean higher digital noise levels and slow shutter speeds make the image susceptible to
blurring to to camera shake.
Nevertheless, some photographers have achieved surprisingly
good results when using high-quality spotting scopes such as those made by Leica,
Swarovski and Nikon. Coupling the camera to the eyepiece can be done with special adapters. Web sized images can look great, but larger prints
may reveal the limitations of the technique.
A few final comments
While you might think that a really long lens is the solution to all wildlife
photography problems, there are several problems with longer lenses. The longer
the lens, the more sturdy the support it needs in order to obtain sharp images. The longer
the lens the larger it is, the heavier it is and the more expensive it is and although you
can shoot from greater distances with longer lenses, the further away from your subject
you are the more air you have to shoot through and the greater the degradation due to
atmospheric effects.
Given the chance, it's usually better to shoot from half the distance
with a 300mm f/4 lens than from twice the distance with a 600mm f/4 lens. The 300mm lens will also
be less than 25% of the weight and less than 20% of the cost of the 600mm.
Perhaps the most valuable tools in the nature photographer's arsenal aren't any of
those described above. They are patience and a knowledge of natural history. Patience is
required, because getting an image of an animal exhibiting natural behavior in its natural
habitat may require just sitting in the right place for hours or even days. A knowledge of
the natural history of the species you are trying to photograph is required to know where
to sit!
© Adorama Camera
|
