Choosing the right one requires you to allow for the shooting situations you can expect. Fortunately, there are plenty to choose from, depending on your requirements and budget.
Unlike wide angle lenses, where a small difference in focal length can make a large difference in angle of view, for telephoto lenses the opposite is the case. Jumps of 100mm or more in focal length deliver relatively small changes in angle of view.
You can get a rough idea of what focal length you need to shoot different sized subjects at different distances by holding your thumb up at arm’s length and seeing how much of the scene is covered. Then use a zoom lens to cover the same area and work out the equivalent focal length.
Each person’s coverage will be slightly different because we all have different sized digits. But, once you have worked out your own parameters, you will have a shortcut that allows you to estimate what focal length you’ll need without having to change lenses.
A fast telephoto zoom lens can make it possible to get action shots like this when you’re in the right location. Shooting data:1/1600 second at f/2.8 with a focal length of 121mm on a Canon EOS-1D Mark III camera. (Photographer: Mitch McMillan.)
The photograph on the left was taken with a 300mm focal length, while a 200mm focal length was used for the one on the right, illustrating the relatively small differences between them in coverage and background de-focusing.
Longer focal lengths are required for close-ups when you can only shoot from a restricted distance. For this shot of a leopard in a tree, a 75-300mm lens used at 300mm on a M4/3 camera provided the equivalent of a 600mm lens on a 35mm camera.
Balancing Size, Weight, Speed and Cost
Suppose you decide you really need a 600mm f/4 lens to photograph a tennis match or birds in bushes? Several questions arise from this choice:
1. Can you afford the high price tag?
2. Can you manage the additional 3.9 kg it will add to your kit?
3. Do you have a strong enough tripod to support camera+lens?
If you answered ‘no’ to any of these questions, some kind of compromise will be required.
If cost is the only obstacle you could consider a secondhand lens. If you make sure its optical performance is tested, you could end up with the lens you want at a price you can afford. And you’ll need a sturdy tripod to support camera and lens.
If weight is the main consideration you could consider swapping to a camera with a smaller sensor format. Changing from ‘full frame’ to APS-C allows you to reduce the lens focal length to between 375mm and 400mm and still cover roughly the same field of view as a 600mm lens on a ‘full frame’ camera.
The shorter lens will almost certainly be smaller and lighter. It will also be roughly half the price of the 600mm lens because less glass is used in its construction.
Drop down to M4/3 format and you reduce size and weight dramatically. But you’ll have to accept a loss of lens speed (expect a maximum aperture of f/6.3 or smaller) and you may find a zoom lens is the only option available. You can still cover almost the same field of view as the 600mm lens, although the M4/3 coverage is a little wider.
A 75-300mm lens on a M4/3 camera can cover the same fields of view as a 150-600mm lens on a 35mm camera in a format that is considerably smaller and lighter, at the expense of lens speed. (Source: Olympus.)
A big plus is that the M4/3 lenses are light enough to use hand-held and either the camera body or lens will include stabilisation. In addition, almost any tripod will be able to support the camera+lens combination.
Lenses for Shooting Sports
Different sports have different requirements and your choice of lens(es) will depend on how close you can get to the action and what types of pictures you want to take. Longer lenses are needed for most sports action close-ups, although shooting motor sports, cycling and children’s team games can sometimes be done with shorter lenses and even wide angle lenses can be used in some situations.
Available light can influence your requirements and so can the types of shots you want. Lens speed is important in dim lighting (e.g. indoor sports) and when you need fast shutter speeds to freeze action. But there may be times when some blurring can lend a sense of speed to the shot.
Most modern cameras, particularly those with larger sensors, produce negligible image noise at ISO 800 and very little up to ISO 6400. Even M4/3 cameras can do well up to ISO 3200. So photographers can start balancing their need for range and speed against the advantages of shooting with smaller sensor cameras.
Wide angle lenses, in this case a focal length of 35mm, lend a different perspective to sports photographs and allow more of the ambience to be captured.
Location can be critical for obtaining close-up shots, even when you use a long focal length like the 300mm lens used for this shot. Bright conditions allowed an exposure of 1/1000 second at f/11, which ‘froze’ the spray and provided plenty of depth of field.
Lenses for Birders
Bird photographers usually lean towards the longest lens they can afford and handle, even when shooting from a hide. This is often because their subjects can be very small and easily spooked.
Although in the past many birders invested heavily in fast super-tele lenses, improvements in high-sensitivity performance and image stabilisation make this less necessary today.
Dropping from ‘full frame’ to APS-C sensor size yields big benefits when range is critical. You gain a 1.5x or 1.6x (for Canon) crop factor extension of the focal length plus a slightly smaller, lighter camera and lens with little or no loss of imaging performance.
Moving from DSLR to M4/3 CSC provides greater portability without significantly compromising imaging performance. The equipment is light enough to carry all day yet capable enough to use in any situation that suits a DSLR.
Tamron’s SP 150-600mm f/5-6.3 Di VC USD, which can be used on both ‘full frame’ and cropped sensor bodies provides plenty of reach for bird photographers who shoot from hides or vehicles.
A 300mm focal lens on an Olympus OM-D camera provides a lightweight combination that is easy to carry and can provide the reach you need to photograph birds like this falcon.
While some noise may be visible in high ISO shots, lower sensitivities should provide similar performance to larger cameras and produce excellent prints.
Lenses for Safari
If you’re going on a genuine safari in Africa, you can manage with modest telephoto lenses because the ‘game’ is generally observed from vehicles. Native wildlife is so accustomed to vehicles it tends to disregard them so you can get close relatively easy.
The ideal focal length range is 70-200mm or 70-300mm in 35mm equivalent. Shorter focal lengths are ideal for photographing larger animals, while longer focal lengths will be excellent for extreme close-ups. They also provide scope for taking action shots of animals hunting or shots of creatures that are easily spooked, such as some of the smaller antelopes.
Convenience zooms allow scope for taking some landscape shots but some photographers prefer to take a second camera with a wider zoom attached for this purpose. The standard 18-55mm kit lens works well for APS-C cameras, while 14-42mm provides an equivalent for M4/3.
Springbok and sand grouse near a water hole, photographed from a vehicle with a convenience zoom lens set at 200mm, using an aperture of f/8 to optimise depth of field.
Sparring gemsbok (oryx), photographed from a vehicle with a 300mm lens on an M4/3 camera. Rapidly changing action presents a chance to take a sequence of shots, either with the camera’s continuous shooting function (if changes are very quick) or at the photographer’s discretion.
Excerpt from Lenses Guide.
