2
Choosing and Using Lenses
Selecting Quality Lenses
Lens-makers generally build two classes of lenses. Prosumer lenses are made for the mass market and do a fine job most of the time. However, because these lenses must be affordable to everyone, they are made with less expensive glass and not built to the same construction standards as professional grade lenses. Lower glass quality means your images may be slightly less sharp (assuming you did everything else right) and the lens is more likely to malfunction at the worst possible time because it isn’t built as ruggedly. That said, prosumer lenses still do a quality job. If your photography technique isn’t flawless, you may never notice a slight loss of sharpness from the lower quality glass used in them. Many of our workshop clients do well with them. If price is a barrier, don’t be afraid to buy less expensive lenses. In reality, your personal shooting technique is far more critical than the glass used in the lens.
Some lenses are less expensive for other reasons that have nothing to do with quality. For example, a 400mm f/5.6 lens is considered a “slow” lens and may not have image stabilization. A 400mm f/2.8 lens is a “fast” lens, and if it has image stabilization, it will be considerably more expensive than the 400mm f/5.6 lens even though the quality of the lenses is the same.
Professional grade lenses use the best optical quality glass and are ruggedly constructed to withstand the elements and abuse from serious photographers. They have seals to protect them from inclement weather
and typically have other features not found on less expensive lenses. Pro lenses tend to be fast lenses, which means the optical glass is physically larger and heavier, thus they cost considerably more. Canon designates their best lenses with the letter “L” while Nikon uses the letters “ED,” which stands for extra low dispersion glass.
Compare lenses carefully when selecting a new one. For an example, let’s compare two popular Canon lenses. Canon sells a 75–300mm f/4-5.6 lens for the low price of $155. Canon also sells the popular 100–400mm f/4.5-5.6 IS USM for $1590. Wonder why one lens costs $1435 more than the other? Actually, there are several good and rational reasons! The 100–400mm f/4.5-5.6 lens covers a larger zoom range. The optical glass is superb because it is an “L” lens which means this lens uses the very finest low-dispersion optical glass. That accounts for much of the difference in price. The most expensive lens also has two critical features that the other lens does not. The 100–400mm f/4.5-5.6 lens has IS which means it is image-stabilized,
A steady line of pelicans flapped by my Land Rover along the shoreline of Lake Nakuru. Though I rarely attempt this, but having no other choice, I hand-held my 500mm lens and panned with it as smoothly as I could. By using a fast shutter speed, I managed to shoot a few sharp images. One advantage of a fast f/4 lens is it focuses faster which is crucial for action photography. Canon 7D, 500mm f/4.0L lens, f/8 at 1/1600 second, ISO 500, and Shutter-priority with zero exposure compensation.
so it can be successfully hand-held at slower shutter speeds and still produce sharp images. Finally, this lens uses an ultrasonic motor (USM). This motor focuses the lens rapidly, making it ideal for action photography. Which is the best lens to buy? It depends on how much you want to spend, how much weight you are willing to carry, and what you plan to photograph. The expensive lens is much heavier at 3 pounds than the 75–300mm f/4.0-5.6 lens at 1.1 pounds.
This mountain gorilla hugs her baby in a dense Rwanda forest. A fast f/4.0 lens was used, along with ISO 500, to sharply photograph them hand-held in the dim light. Nikon D200, 24–85mm f/4 lens at 42mm, f/5.6 at 1/160 second, ISO 500, and manual exposure.
Many photographers don’t want to carry extra weight. If you tend to photograph still objects, then you don’t need the ultrasonic motor of the high priced lens either. There is no wrong answer here. It depends on your needs and budget.
Here’s our strategy for buying lenses. Our career depends on us capturing high quality nature images shot after shot. We are competing against the finest photographers in the world since we sell to the same markets and compete for the same workshop clients. We need the best tools to help us capture quality images efficiently and quickly. Therefore, we always buy the best quality lenses made by Canon and Nikon, no matter what the cost and weight. We are believers in buying
These two male cheetahs rest on a small observation mound in the Masai Mara. The thick overcast forced the use of ISO 800 and a slow shutter speed. A large bean bag, careful focus, and activating image-stabilization were necessary to improve the odds of shooting sharp images. Canon 5D Mark II, 500mm f/4 lens, f/6.3 at 1/100 second, ISO 800, and Shutter-priority with a +2/3-stop exposure compensation.
the best lenses made, but we prefer to save money by not buying (usually) the top-of-the-line cameras which are far too expensive compared to the cameras for the semi-pro market. Due to rapid changes and constant advances in technology, cameras quickly become seriously outdated as well as obsolete while lenses do not. We believe in spending our dollars on quality lenses.
The best quality lenses are more critical for wildlife photography than for landscape and macro photography for a couple of key reasons. The majority of wildlife images are captured with lenses longer than 300mm in focal length. Translated, this means you must shoot using high shutter speeds to capture sharp images. This forces you to shoot fairly wide open most of the time, so you’ll be using apertures in the f/4 to f/5.6 range a lot.
Due to the laws of optics, most lenses are sharpest two to three stops down from the fastest aperture on the lens. With a 300mm/4.0 lens, the sharpest apertures will be at f/8 to f/11. The highest quality glass delivers sharper images wide open than lenses with normal quality glass. Second, expensive lenses tend to be faster. For example, a 300/2.8 lens is two stops faster than a 75–300/5.6 lens. The viewfinder is two stops brighter with the 300mm lens than the slower zoom lens. This means autofocus is more accurate and much quicker. If you must focus manually, it is easier to do this with the faster lens because seeing the subject in the brighter viewfinder is much easier. It is easier to focus with less depth of field appearing in the viewfinder as the subject snaps into focus.
LENS SPEED
Dividing the maximum diameter of the aperture into the focal length of the lens determines the speed of the lens. Let’s compare two lenses currently offered by Canon to examine the pros and cons of lens speed. Canon offers a 300mm f/4 and a 300mm f/2.8 lens. The 300/4 lens costs $1260 while the 300/2.8 lens empties your wallet to the tune of $4200. The main difference in the price of these lenses is the size of the high-quality optical glass being used. Both are “L” lenses, but the glass required to make the f/2.8 lens is considerably larger than the f/4.0 lens. It is easier to use a faster shutter speed with the f/2.8 lens. The viewfinder is brighter which helps the camera autofocus faster, more accurately, and preserves autofocus in dimmer light. Teleconverters work better on faster lenses because you are more likely to maintain fast autofocus. Finally, f/2.8 delivers a shallower depth of field than f/4, which is useful for creating a soft background without detail.
Unfortunately, fast lenses are heavy, often a few pounds heavier than a slightly slower counterpart. They are painfully expensive and use larger, more expensive filters. Finally, they are more difficult to travel with because they are both heavy and large, so they take up a lot of space. Despite their weight and size, fast lenses are such pure joy to use once you accept their size, and develop the superb shooting techniques required to achieve the quality they are capable of delivering.
IMAGE-STABILIZED LENSES AND CAMERAS
Image stabilization is a fairly new feature built-in to many lenses or built-in to the camera body itself. If it is built-in to the lens, some optical elements move to counteract lens movement, producing sharper images. Some camera systems, such as Sony, have image stabilization in the camera body and not in the lenses. Both systems seem to work.
Unhelpfully, different companies use various terms to describe image stabilization. Canon calls their lenses image-stabilized (IS) while Nikon calls them vibration reduction (VR) lenses. No matter what the company calls it, image stabilization allows you to capture tack sharp images using slower shutter speeds. Image stabilization is especially useful when shooting handheld, something you should do only when there is no way to use a tripod. It is also helpful for photographing in high wind or when shooting on a tripod or a bean bag from a vehicle.
Image stabilization is useful and necessary at times. Beware, do not use it as a crutch. Too many photographers have adopted image stabilization to avoid using a tripod. That’s a huge mistake! While image stabilization does help you shoot sharp images, it does have its limits. Using a 500mm telephoto lens still works best on a tripod in all situations where using a tripod is possible. Focusing carefully and using fast shutter speeds are crucial for achieving sharp images with telephoto lenses because they magnify the image greatly. It’s simply too difficult to hand-hold a large lens and keep it still to maintain your composition. Like it or not, using a sturdy tripod is still the best answer in most situations.
Image stabilization is enormously useful when using a telephoto lens on a tripod during windy conditions. The wind causes the tripod-mounted lens to steadily vibrate, but image stabilization counteracts the effect, producing sharper images. This technology is also invaluable when photographing from a boat. A tripod actually makes things worse if the boat is rocking at all.
When the boat is rocking, you are much better to shoot handheld, use fast shutter speeds, and use image stabilization because your body absorbs some of the rocking motion. We use large bean bags on Kenya wildlife safaris and in national wildlife refuges where we photograph from the car window. Even though the vehicle ignition is turned off, the camera isn’t perfectly still as it rests on the bean bag. Image stabilization is extremely helpful in this situation. We also sometimes use image stabilization when photographing action, especially birds in flight, but use it as an option where the lens only stabilizes one direction, usually vertical, and not the horizontal direction we are panning.
While image stabilization is useful at times, it does have its disadvantages. First, it tends to make some photographers lazy. They decide to shoot hand-held and not use a tripod when they easily could. That’s always a bad choice and their images suffer for it. Of course, we know you don’t fit into that category because you want the best possible images. Second, the number of images-per-second (burst rate) that you can shoot may decline. This is the main reason we normally don’t use image stabilization when photographing wildlife in action. Third, batteries are depleted faster.
Be aware that most image stabilization systems have two modes. The standard mode (Mode 1 if shooting Canon)
Lake Nakuru often attracts more than one million flamingos. This pair of lesser flamingos is fleeing from a marauding spotted hyena. Due to the high 1/2000 second shutter speed, image stabilization is not helpful and therefore turned off. Canon 7D, 500mm f/4 lens , f/8 at 1/2000 second, ISO 500, and Shutter-priority with no exposure compensation.
reduces vibration in both the horizontal and vertical directions. If you are panning with a moving subject, use Mode 2. This stabilizes the lens only in one direction and not in the direction you are panning. To illustrate this, imagine panning with a Canada goose flying from left to right. The motion is horizontal, so in Mode 2, the lens only stabilizes the lens for up and down vertical movement, not horizontal movement. Unfortunately, Canon puts the off/on and Mode 1/2 switch on the lens. When shooting on a bean bag, pushing the lens forward on the beanbag often turns off the IS and changes the mode switch to Mode 2. This problem is easily solved by using duct tape. I set the IS switch to On and the Mode to Mode 1. Then I duct tape these switches to keep them in place. Of course, when IS isn’t wanted or Mode 2 is wanted, then the duct tape must be removed to change the switches. Hopefully, lens builders will offer better lenses in the future that let photographers lock switches in place.
PRIME VS. ZOOM LENSES
Canon 600mm f/4, Nikon 300mm f/2.8, and Sigma 150mm f/2.8 lenses are all examples of prime lenses because they have fixed focal lengths. Zoom lenses offer a variety of focal lengths within a set range. Examples include Canon 100–400mm f/4.5–5.6, Nikon 200–400mm f/4, and the Tamron 200–500mm f/5.0–6.3 lenses.
PRIME LENS ADVANTAGES
Prime lenses offer many advantages over zoom lenses. Most have faster lens speeds, faster autofocus, produce sharper images, and most focus closer than zooms covering the same focal length. With all of these advantages, are prime lenses the best way to go? Well, uh, it all depends.
Faster lenses are a joy to use, but being able to shoot using higher ISOs removes some of their advantages. The autofocus may be slightly slower with a zoom lens, but that is only critical when photographing really fast action. Zoom lenses have more glass elements than prime lenses. This means they may be slightly less sharp and are more prone to flare than
This mule deer doe is calmly looking at us, and the flowers she hopes to eat, in Barbara’s garden. The fast f/4 lens provides the shutter speed necessary to shoot sharp images. Canon 1 D Mark III, 300mm f/4 lens, f/4 at 1/250 second, ISO 400, and manual exposure.
Greater prairie chickens are fascinating to photograph when they assemble on their breeding leks during April in Nebraska. It’s necessary to hide in a blind and be in position at least one hour before sunrise because they dance most vigorously at first light. Anytime you must stay in one spot, such as in the blind, and the subject is free to move closer or farther away, a zoom lens is vastly superior to fixed focal length lenses. Barbara’s superb Nikon 200–400mm f/4 lens works perfectly here. Nikon D2X, Nikon 200–400 f/4 lens with a 1.4x teleconverter at 550mm, f/6.7 at 1/250 second, ISO 100, and manual exposure.
fixed focal length lenses, but these differences are quite minor and not a significant enough reason to avoid using zoom lenses, especially if the zoom lens is made with the best quality glass. Your photography technique is far more crucial for achieving sharp images than the lens. A lens that is capable of focusing close is beneficial, but with the use of extension tubes, even zoom lenses can be made to focus close. These negative factors for zoom lenses do push many serious photographers (including us) toward prime lenses. We often use prime 500mm f/4.0 and 300mm f/4 lenses in our wildlife photography, but do use zooms quite often as well. Indeed, our favorite wildlife photography lens is a Nikon 200–400mm f/4 lens.
ZOOM LENS ADVANTAGES
Regardless of how you look at it, zoom lenses have some tremendous advantages for wildlife photographers that must not be forgotten. First, they contain many focal lengths in a single package. A 70–200mm f/4 zoom lens has every focal length between 70mm and 200mm inclusive.
Covering this range with three prime lenses is incomplete, far more expensive, and generates a lot more bulk and weight to carry with you. Second, zooms make it easy and quick to change compositions for both still and moving subjects. Anyone who has ever been anchored to one spot while hiding in a photo blind, or when shooting from a vehicle, knows the frustration of having the subject move too far away or too close when using a prime lens. A zoom works far better in this situation. Third, while most wildlife photographers use few filters, if you do use any, you will find that a single filter that is made for your zoom lens works at every focal length contained in that lens.
TYPES OF ZOOM LENSES
VARIABLE APERTURE
Most zoom lenses are built to allow the maximum aperture to vary with the focal length as you zoom the lens. The Nikon 80–400mm f/4.5–5.6, for instance, begins with a f/4.5 lens speed at the 80mm setting. As you zoom to longer focal lengths, the maximum aperture gradually slows until you reach f/5.6. Lenses are made this way because they are lighter, more compact, and much less expensive to build. This means the lens-maker can sell a bucketload of them.
CONSTANT MAXIMUM APERTURE
The maximum aperture of these zooms does not vary. Examples include the Canon 70–200mm f/2.8, Nikon 200–400mm f/4, and Sigma 24–70mm f/2.8. Since the aperture does not vary, the glass elements must be extra large to maintain the maximum aperture over the zoom range. These lenses are pricey, heavy, and bulky. Since they don’t slow down as you zoom to the longer focal lengths, your viewfinder stays bright and the autofocus is both faster and more accurate.
Many “pro grade” zoom lenses maintain the constant maximum aperture. Maintaining lens speed is a highly worthwhile feature because you need shutter speed when photographing wildlife to stop subject motion and arrest camera movement. However, once again, the ability to use higher ISOs, such as the ISO 800 with excellent quality, reduces the constant maximum aperture advantage somewhat.
OUR RECOMMENDATIONS
We greatly prefer prime (non-zoom) lenses for any focal length over 400mm. Many world-class wildlife photographers are our personal friends and virtually all of them use a prime 500mm or 600mm super-telephoto as their main lens for capturing exquisite wildlife images worldwide. Canon even offers a fine 800mm f/5.6 lens that works beautifully. Unfortunately, the $10,000 plus price tag prohibits many photographers from buying it, including this author, who would be wild about using it. For the record, I use a Canon 500mm f/4.0 while Barbara uses a Nikon 500mm f/4.0 lens.
As I write this, I do plan to switch to the new Canon 600mm f/4.0 lens for a bit more magnification.
To cover the shorter focal length ranges, most wildlife photographers tend to use zoom lenses, both variable aperture and constant maximum aperture models. Barbara uses her Nikon 200–400mm f/4.0 lens for the vast majority of her wildlife images. She only uses her 500mm lens when she needs the absolute maximum magnification possible. Otherwise, the capability of being able to zoom from 200mm to 400mm is just too much of an advantage to give up. She also uses a Nikon 24–85 and 70–200mm lens. I do well with my Canon 24–105mm f/4 and 70–200mm f/4 lenses. I have used the Canon 100–400mm f/4.5–5.6 lens, but sold it a couple years ago as I do not like push–pull zooms. I am eagerly awaiting the arrival of the Canon 200–400mm f/4 lens that hopefully will become available by 2013. Although we use plenty of zoom lenses, we always spend the extra money to buy the professional grade lenses with the best optical glass. We feel the difference is crucial to our ongoing success in the brutally competitive field of wildlife photography.
White-winged doves are popular game birds. Being hunted during the autumn makes them less approachable than non-game species. A 500mm lens was necessary to maintain a substantial working distance, even when hidden in a photo blind, to avoid scaring it away. Canon 1 Ds Mark II, 500mm f/4.0 lens, f/9 at 1/125 second, ISO 250, and manual exposure.
WIDE-ANGLE LENSES FOR WILDLIFE
Beginners to wildlife photography might think everything is done with a long lens. But, there are wildlife hot spots around the world where a wide-angle lens works best for capturing fine wildlife images. We have been fortunate to be able to travel the world during our 35-year career. In years past, we have photographed in the Arctic Circle, Antarctica, Midway Atoll, the Galapagos Islands, Tanzania, Kenya, Rwanda, northern Japan, the Falkland Islands and Alaska, to name but a few spots. Unfortunately, most of these places were visited during our film shooting days, but we hope to return eventually to use our new digital cameras. Since we feel every image in this book should be produced from a digital camera, we have not used any of our film images in any digital books, magazine articles, or classroom teaching. On many oceanic islands, wildlife is unaccustomed to land-based predators and show little fear of humans. It is often easy and safe for the photographer and the animal to be very close together.
Wide-angle lenses are terrific for photographing large groups of animals at close range. These lenses let you capture wildlife in the foreground and the landscape behind them. Lenses such as the 17–40mm f/2.8 and 24–105mm f/4 are excellent for these types of images. During our film days, we commonly photographed busy colonies of penguins in the Falkland Islands and Antarctica with short zoom lenses. We did use our digital cameras recently in northern Japan to photograph whooper swans. Using a 17mm lens only a couple feet from the nearest whooper swan produced a compelling foreground full of swans with the snow-covered mountains in the background.
Many short zoom lenses are offered today. As a guideline, look for two or three zoom lenses that cover the 17–200mm range. I use Canon’s 17–40mm f/2.8, 24–105mm f/4, and 70 –200mm f/4 lenses to nicely cover this range. Resist the temptation to buy one lens that covers everything.
Lenses do malfunction, and usually in remote places when they are hard to fix or replace. It’s wise to have at least two lenses covering similar, but not exactly identical focal lengths, rather than using one lens to cover everything. If the only lens you have malfunctions, what will you do? Losing your only lens might not be a serious problem when you are at home, but what if you are on a once-in-a-lifetime photo tour in Kenya?
I listed above the zoom lenses I use with my Canon system. Lenses tend to come and go. Therefore, rather than list a bunch of lenses for each system that may or may not be around when you read this, just look at the lenses made for your camera and consider selecting similar ones to duplicate my strategy. These zoom lenses have worked well for me, but your needs may differ, so consider what I use merely as a guideline to follow.
INTERMEDIATE LENSES
Lenses that cover the 100–300mm focal lengths are interme diate telephoto lenses. These lenses are useful for wildlife photography when you can get very close to small animals or
Greater kudus are spectacular mammals. We sometimes find them at Samburu National Reserve. This buck posed nicely when it caught the scent of a nearby leopard. The Canon 300/4 lens framed the animal perfectly. Canon 5D Mark II, 300mm f/4 lens, f/8 at 1/800 second, ISO 400, and manual exposure.
a bit farther away for larger animals. A 75–300mm zoom is terrific for capturing images of wildlife while preserving the flexibility of being able to change the composition easily by zooming the lens. For example, a 300mm lens is all you need to photograph yellow-bellied marmots at Sheepeater Cliffs in Yellowstone National Park during the summer months when they are active. These animals are accustomed to seeing humans at close range. Marmots are adorable and beg for food, but resist the urge and don’t feed them. It’s against the park rules and unnatural human food isn’t healthy for them anyway.
During late September in Yellowstone, elk bugle in the meadows along the road. Often, all you need is a 300mm lens to fill the frame with the magnificent bull elk. Always avoid blocking their path and always stay at least 25 yards away from them. Park rules prohibit approaching closer and it isn’t safe anyway because sometimes elk do attack humans. Although the elk in the front country of Yellowstone are habituated to humans, I prefer to stay about 40 yards away and use 300mm focal lengths for safety and to avoid disturbing them.
LONG LENSES
Prime lenses of 500mm and larger are widely used by professional and serious amateur wildlife photographers. Long prime lenses have many advantages. They offer great working distance and high magnification. This lets you fill the image with a subject some distance away. These long focal lengths have a narrow angle of view which tends to produce uncluttered backgrounds, a very pleasing side benefit.
On the negative side, long lenses are extremely expensive, $5000 to $8000 is a typical price for a new one. They are both heavy and bulky, making them more difficult to carry with you on airplanes and in the field. Most don’t focus particularly close, so you may not be able to fill the image with a small subject such as a wren, but you can add extension tubes as explained in Chapter 1. Your shooting technique must be superb to consistently capture sharp images with these lenses as well. If you make a mistake with these big lenses, you’ll see it in your images!
THREE WAYS TO OWN A SUPER-TELEPHOTO LENS
BUY A PRIME 500MM OR 600MM LENS
Your choices are simple if you are using Canon or Nikon. Both offer 500mm f/4 and 600mm f/4 lenses. The 600mm lens is larger and heavier than the 500mm lens. Therefore, we have always used the smaller 500mm lens for both our Canon and Nikon systems. However, if we photographed wildlife exclusively (we are avid macro and landscape photographers, too), we would use the 600mm lenses to get more magnification. If you use Olympus, Pentax, Sigma, or Sony/Minolta; Sigma offers a 50–500mm f/4.0–6.3 telephoto zoom for a little over $1000. We are not fond of zooms in this range because they tend to be slow to autofocus and may suffer from sharpness problems. It is difficult to make a truly sharp lens when such a wide zoom range is covered. Besides, you can’t expect a $1000 lens to perform as well as one that costs thousands of dollars more. You get what you pay for. However, this lens may be perfectly suitable for your needs.
USE TELECONVERTERS ON 300MM OR 400MM LENSES
Using a teleconverter behind a 300mm or 400mm lens is a high quality way to get a super-telephoto lens at a lot less cost. Nikon offers a 300mm f/4 lens for about $1400. Add a 1.4x or 1.7x Nikon teleconverter for a couple hundred dollars more and you have a far more affordable super-telephoto lens that is easy to carry and produces excellent image quality—if you do your part by employing superb shooting techniques. Nikon offers three teleconverters, the 1.4x, 1.7x, and 2x. Teleconverters multiply the focal length of the lens by the power of the teleconverter. Here’s a table to simplify it.
Look at the table. Note that multiplying the power of the teleconverter by the focal length of the lens determines the new focal length. Also, notice the teleconverter costs you lens speed. A slower lens means the viewfinder is darker, you can’t shoot as wide open to blur the background, and your autofocus may slow down or you may lose autofocus
| Focal length | Lens speed |
| No teleconverter 300mm | f/4.0 |
| 1.4 × 420mm | f/5.6 |
| 1.7 × 510mm | f/7.1 |
| 2 × 600mm | f/8.0 |
altogether. Some cameras cannot autofocus at f/8 maximum apertures. Teleconverters are a superb way to reach the longer focal lengths, but don’t overdo it. They have glass elements that are added to the optical path, so expect to lose some sharpness. The more powerful the teleconverter, the more sharpness you lose. We suggest starting with the 1.4x teleconverter, especially if the camera you use has a crop factor. Although teleconverters have some disadvantages, they also have important positives which include making the lens longer to let you capture bigger images of the subject. The angle of view is narrower, too, so it produces less cluttered backgrounds due to the reduced field of view. To achieve the best quality, it’s a worthwhile practice to buy teleconverters made by the lens manufacturer and not by third-party vendors.
Many photographers immediately buy the more powerful 2x teleconverter, even though the optical quality is slightly less than the 1.4x or 1.7x teleconverter and they may lose autofocus with the slower lens. They want to double the image size of the subject. Question: Does the 2x teleconverter double the image size? Suppose you are photographing a Canada goose with a 300mm lens and the area occupied by the goose on the imaging sensor is 1/4 × 1/4 inch. If you add a 2x teleconverter to the lens, it does double the height and width of the goose to 1/2 inch on the sensor. However, the area occupied by the goose is not doubled. Rather, the area is quadrupled and may be more magnification than you need. The 1.4x teleconverter approximately doubles the size of the goose in the image and the sharpness quality will be better. Therefore, consider buying a 1.4x teleconverter first. Only go to more powerful teleconverters if you really need them and can live with their disadvantages.
Always test a lens and teleconverter combination to make sure it works well together. Use a newspaper or magazine page with fine print for the test target. Tape the test target to a wall to keep it completely still. Using a tripod, manually focus the lens/teleconverter combination to make the print as sharp as possible. It helps to use a magnified live view image to make sure you precisely focus on the print. Make sure the plane of the imaging sensor and the test target are parallel. This is easy to do. Focus the test target on the right side of the image. Now look at the left side. If the print isn’t in equally sharp focus, then you are not perfectly parallel. Use flash to illuminate the newspaper. The short flash duration freezes any camera
European storks winter in central Africa and gather in Samburu National Reserve when the grasshoppers are abundant. This individual let me easily back-button focus on its eye and then recompose to improve the composition. Canon EOS 1 D Mark III, Canon 500mm f/4 lens, f/7.1 at 1/1600 second, ISO 400, and manual exposure.
It wasn’t possible to drive closer to this European stork. Therefore, I put a Canon 1.4x teleconverter behind the lens to approximately double the size of the bird in the viewfinder. Many photographers assume a 2x teleconverter is needed to double the size. In reality, the 2x teleconverter doubles the height and the width which comes closer to quadrupling the size of the subject. Canon EOS 1 D Mark III, Canon 500mm f/4 with a 1.4x tele-converter, f/10 at 1/800 second, ISO 400, and manual exposure.
movement that might be caused by wind, mirror slap, or any other reason. Flash provides a true test of what this combination of glass elements really can do. Once you know the glass can get the sharpness you want, try some shots using natural light to see if your shooting technique is adequate. Be sure to keep the shutter speed at 1/125 second or more, even on a tripod.
USE THE CROP FACTOR FOR A LONGER LENS
Except for a few much more expensive cameras that have a full-frame sensor size of 24mm × 36mm, most cameras have a smaller sensor. Therefore, crop factor refers to the relationship between a “full-frame” sensor and some smaller sensor. Common crop factors are 1.3x, 1.5x, 1.6x and 2x. This means any lens appears to have a longer focal length when it is used on a camera with a crop factor. If you attach a Nikon camera, such as a D300s, with a 1.5x crop factor to the 300mm f/4 lens, it changes the field of view to that of a 450mm lens. Although the lens is still a 300mm lens, it really acts photographically like a 450mm lens because the field of view is cropped, making the subject appear larger in the image. It seems that there is more magnification, but this apparent increase in magnification is merely a cropping of the image that would have been captured with a full-frame sensor. Some authors and photo teachers call it the magnification factor, but nothing is really being magnified. Therefore, “crop factor” seems to be the more accurate and descriptive term to use.
Whether you wish to think of it as the “crop factor” or the “magnification factor,” your subject still appears pleasingly larger in the viewfinder. A larger subject in the viewfinder is easier to focus precisely on the eye with both autofocus and manual focus techniques. The “crop factor” is one of the great equalizers in digital photography. With a small sensor camera, everyone can enjoy the benefits of a long lens if you obtain any lens with a 300mm focal length or greater.
THE CROP FACTOR WITH A TELECONVERTER
Almost anyone can afford a used 300mm f/4 lens. With a 1.4x teleconverter, the lens optically becomes a 420mm f/5. lens. With a 1.5x crop factor, the lens now provides a field of view of a whopping 630mm f/5.6 (420 × 1.5 = 630) supertelephoto lens. You do lose one stop as the lens slows from f/4 to f/5.6 due to the 1.4x teleconverter, but you still have a fairly fast lens that will autofocus! Now everyone can enjoy the benefits and advantages of a long lens. It is affordable and the weight is easily handled by most photographers.
Crop Factor Advantages
You’ll remember that the crop factor makes the lens appear to be a longer focal length. It really isn’t, but it feels that way. Small sensors tend to have fewer pixels than larger sensors. This means you can shoot more images per second for a faster burst rate than cameras with full-frame sensors.
Also, since file sizes tend to be smaller with the small sensor cameras, the burst depth—the number of images you can shoot continuously before filling up the camera’s buffer—is greater. These two items are hugely advantageous for capturing wildlife action and the primary reason we normally use small sensor cameras to photograph wildlife.
Crop Factor Disadvantages
The smaller number and size of the pixels are the main drawbacks to using small sensor cameras. As pixel size decreases, the signal-to-noise ratio becomes more unfavorable, which increases digital noise. Further, since you typically have fewer pixels to begin with—compared to a full-frame sensor—you have less opportunity to crop the image later on and still retain sufficient image quality. Cropping the image too much may lose too many pixels to make the print size you want and have it still look sharp. The crop factor does make wide-angle lenses longer. This means a 24mm lens used on a camera with a crop factor of 1.5x generates a field of view of a 36mm lens. This is a frequent problem for landscape photographers, but not so serious to the wildlife specialist. We do shoot wide-angle wildlife scenes, but use our large sensor cameras when doing so.
Ecuador’s exquisite toucan barbet is readily attracted to bird feeding stations offering fruit. This medium-sized bird required a 400mm focal length plus a 1.4x teleconverter to make it fairly large in the image. Barbara used a fast 1/250 second to help her get a sharp image. She used tele-flash to improve the colors in the feathers and brighten up the dull natural light in the forest canopy. Nikon D300, Nikon 200–400mm lens at 400mm, 1.4x tele-converter, f/5.6 at 1/250 second, automatic flash, ISO 640, and manual metering.
TILT/SHIFT LENSES
These unique lenses have features that other lenses don’t have. They are made to permit the image to be shifted about the sensor. The lens can be bent to allow Scheimpflug’s principle to be used to maximize depth of field.
The shifting capability is ideal for keeping vertical lines vertical. Thus, landscape photographers greatly appreciate this feature, especially if they photograph tall trees or buildings. There is little need for being able to shift the image on the sensor in wildlife photography. However, the tilting mechanism is incredibly helpful to wildlife photographers in situations where numerous animals are crowded close together and you want to get everything sharp. Penguin and albatross nesting colonies, herds of wildebeest or zebras, a shoreline of marine iguanas in the Galapagos, dense flocks of whooper swans in northern Japan or mallards at the local park are all perfect subjects for a lens that can tilt.
During two trips to Antarctica, Canon’s 45mm and 90mm T/S lenses worked tremendously well to photograph magnificent colonies of penguins. The tightly packed nesting colonies could be approached closely without disturbing the birds. The nearest penguins were only a few yards away and the densely packed colony extended for a hundred yards or more. At this shooting angle, you could stop down a normal 50mm lens to f/22 to extend the depth of field through the penguins, but some of the most distant penguins still weren’t sharply focused because the plane of focus was almost perpendicular to the plane that passed through all of the penguins. Stopping down to f/22 forced a slower shutter speed. Although the penguins remain stationary as they incubate their eggs, they still move their heads a lot as they squabble and poke at their hostile neighbors. Higher shutter speeds are necessary to arrest this motion. If proper exposure at ISO 400 is 1/250 second at f/11, stopping down to f/22 will cost you two stops of light, forcing the use of a slower 1/60 second shutter speed. Unfortunately, the 1/60 second shutter speed doesn’t arrest the head motion of the quarreling penguins.
With a Canon 45mm tilt/shift lens, a colony of penguins is easily sharply shot. Begin by focusing on the head of the nearest penguin. Looking through the camera’s viewfinder, notice the birds in the background are seriously out of focus. Now tilt the lens a couple degrees down, refocus on the foreground bird, and peer at the birds in the background. They should be getting sharper. Keep adjusting the tilt down until all of the heads are sharp from foreground to background. If you tilt the lens too much, some of the heads go out of focus again. When you determine the proper angle to make all of the heads sharp, meter in the usual way, and shoot the image. You don’t need to stop down the lens to f/22 because all of the heads are sharp wide open due to Scheimpflug’s principle. Now you can keep the camera set at ISO 400, f/11 and 1/250 second. The higher shutter speed helps to freeze bobbing heads and the tilt feature of the lens lets you align the plane of focus with the heads of the penguins.
Sadly, you may not be able to get a lens like this because most camera makers do not offer tilt/shift or perspective control lenses. Fortunately, the two camera systems most used by wildlife photographers—Canon and Nikon—do offer several. Canon offers 17mm, 24mm, 45mm, and 90mm tilt/shift lenses. Nikon has 24mm, 45mm, and 85mm PC lenses. Generally, for wildlife photography, the longer focal lengths are the most useful.
LENS ACCESSORIES
POLARIZING FILTERS
Wildlife photographers tend to avoid using polarizing filters because these filters cost them 1.5 to 2 stops of light. Thus, you lose two shutter speeds, making it more difficult to capture sharp images with long lenses. However, now that cameras offer excellent quality when using higher ISOs, such as ISO 400 and ISO 800, it is easier to use polarizers and still maintain sufficient shutter speed.
During a couple of photo safaris we were leading in Kenya, we used polarizers more, but found they had little positive effect on lions, giraffes and other furry critters unless they were against a blue sky background.
After extensive experimentation, we have largely abandoned polarizers for wildlife photography, except for certain subjects or situations. Polarizers are useful for reducing glare on highly reflective animals like crocodiles and hippos. Polarizers do improve colors when photographing birds against a blue sky that has an abundance of polarized light. If the sun is due east and close to the horizon, draw an arc that begins due north and goes up and over you and down to due south. That portion of the sky has the greatest amount of polarized light. When turned properly, the polarizer removes much of the polarized light, darkening the sky in the process. The polarizer has little to no effect when shooting directly at or away from the sun. The polarizer is incredibly useful for reducing glare associated with animals in the water such as the enormous flocks of lesser flamingos at Lake Nakuru.
Polarizers that fit super-telephoto lenses, such as a Canon 500mm f/4 are huge and expensive. Fortunately, these big lenses accept small drop-in polarizing filters. Drop-in filters are much less expensive, lighter to carry, and easier to use than large polarizers that screw onto the front of the lens. With smaller lenses like a 300mm f/4, the regular polarizers that attach to the front of the lens work fine.
PROTECTION FILTERS
It appears the vast majority of amateur nature photographers and many pros use UV or Skylight filters on their lenses to protect the lens. However, be aware the lens manufacturer optimizes the lens performance to produce the finest quality without any extra glass being added to the optical path. Adding any glass to this optimized optical path will decrease the quality of your images, though the decrease may be slight. A single well-made filter will cost you a little quality, but the image is probably fine for professional needs. However, some really cheap “protection” filters degrade the image horribly. In the field workshops we teach, some “protection” filters are so bad that it is impossible to achieve sharp focus. If you believe you need a “protection” filter, then go ahead and use an expensive high quality one.
However, if you use a polarizing filter at times, never stack the polarizer on top of the “protection” filter. Adding all of
Lenses with Hoods. It’s crucial to develop superb photographic habits! Always use clean lenses that are protected with a properly installed lens hood. Avoid using protection filters. Instead, handle your lenses carefully and always use the lens hood to protect it. Canon EOS 5D Mark II, Canon 100mm macro lens, f/22 at 1 second, ISO 500, and manual exposure.
that extra glass to the optical path may seriously degrade image quality. You will lose sharpness, obtain less color saturation, and suffer problems from flare more often.
In the interest of full disclosure, we haven’t owned or used a “protection” filter in more than 35 years. Instead, we always use a lens hood, handle our equipment carefully, and have yet to suffer any damage that could have been prevented by using a “protection” filter. Have we damaged lenses? Yes. Once we dropped a small lens that fell 100 feet to the rocks below, but no “protection” filter could save it. The sound of a $300 lens disintegrating as it explodes on the rocks below does make your hair stand up on end!
Although you know our extreme dislike of “protection filters,” we do use polarizing filters when their benefits outweigh the slight loss of image quality and the inconvenience of using them.
LENS HOODS
Sadly, some photographers fail to use lens hoods, even when it is built into the lens. All they have to do is pull it out, yet many don’t. Part of superb shooting technique is always using your lens hood. The hood greatly reduces flare in the image. Flare is created when light strikes the front glass of the lens from the side. Instead of this light being focused on the sensor, it bounces around among the glass surfaces inside the lens and causes out of focus hot spots (flare) in the image. This reduces contrast and diminishes color saturation.
It is always wise to use the lens hood. The hood not only helps you capture higher image quality, but it nicely protects the front of the lens. The hood deflects sticks that might scratch the lens. If you happen to drop the lens, should it fall on the lens hood first, the hood might bend, but save the expensive parts of your lens. The hood keeps snowflakes and raindrops away from the glass, helping to prevent smudges from forming on the glass.
It’s true the lens hood makes it more difficult to use a polarizing filter because the filter has to be turned to get the effect you want. If you can’t reach in with one finger to turn the filter, then take the lens hood off, turn the filter to the desired position, and replace the lens hood. It really doesn’t take much extra effort or time to shoot this way.
CLEANING LENSES AND FILTERS SAFELY
The high-grade optical glass in your lenses and filters directs the rays of light to the imaging sensor. The glass must be as clean as possible for it to perform at its best. Keeping lenses clean is absolutely crucial to image quality. Everyone must master the techniques for keeping the glass clean. Fortunately, cleaning lenses well is easy. Follow these simple steps to become a lens cleaning “guru.”
PREVENTION
Always keep the front and back lens caps on your lenses anytime you aren’t using them. Preventing dirt and smudges in the first place is always the best policy. However, no matter how careful you are, dirt will eventually find its way to the glass. This dirt must be removed to maintain the quality of your images. Smudges degrade the image even more because they cause relatively large out of focus blobs in your images. Fortunately, smudges are easy to prevent. Never touch the glass with your fingers. Most of the smudges that appear on our lenses are caused by wayward raindrops, water drops thrown at the lens from waterfalls, or melted snowflakes. Each of these causes a smudge when the water dries on your lens.
CLEANING YOUR LENS
There is always a bit of dust on the lens when you take the protective caps off of it. Use a Giotto Rocket Blower to blow the dust off. Often, this is all that is necessary. When both ends of the lens are clean, mount the lens on the camera and the hood on the other end. Don’t use canned air to clean the lens. Canned air sometimes squirts a liquid on the glass, causing a somewhat difficult to remove smudge.
If the Giotto Rocket blower doesn’t remove all of the dust from the surface of the glass, then you must gently and carefully rub the glass with a clean microfiber cloth. Then blow the lens off again with the rocket blower. This should work most of the time.
If a smudge, dust, or other debris remains stuck to the lens, put a few drops of lens cleaning solution on the clean microfiber cloth or lens paper expressly made for this purpose—not directly on the lens to avoid having excess fluid leak into the interior of the lens—and gently rub the lens. Begin in the middle of the lens and rub the lens in a circular motion until you get to the outer edge of the glass. Make sure all of the lens cleaning fluid is removed. Blow the lens off again with the rocket blower to remove any lint from the cloth.
This cleaning procedure works perfectly for us. We do occasionally wipe the metal surfaces of the lens off, too, with a damp microfiber cloth. Do make sure the cloth isn’t too damp. You don’t want water seeping into the interior of the lens. It helps to wash both the front and rear lens caps from time to time to remove any dirt they contain. Vacuuming your camera bag occasionally is helpful, too.
