Big guns

Fast telephoto lenses with focal lengths longer than 400mm are generally too large to use hand-held. A monopod (shown above) will provide some stability for photographers who need to shift shooting positions frequently –  but a tripod will be more reliable.

Long telephoto lenses are most commonly used for sports and wildlife photography, although they can be used for many other applications. Unfortunately, they tend to be rather large, are often heavy and can be difficult to hold steady when framing shots.

Because distant objects cover much more of the lens’s angle of view than they would with a wide-angle lens, subjects appear closer to the camera. This magnification also magnifies any camera shake that occurs during the exposure.

Tele lenses usually become longer, larger in diameter and heavier as their focal length increases. Beyond a certain point (which varies with the photographer’s strength and experience), a lens becomes difficult to use hand-held.  

Thanks to image stabilisation, hand-held shooting can be possible with some long lenses, particularly those in the 200mm to 400mm range. Beyond that point, even if stabilisation is available, longer lenses should be tripod mounted.

Choosing a long lens

Selecting a longer lens should be a matter of balancing lens speed against overall size and weight. Consumer tele lenses with focal lengths between 200mm and 500mm tend to have maximum apertures between f/4 and f/5.6, which isn’t particularly fast.  

Professional lenses are often a stop faster (which means they transmit twice as much light). However, with each increment of speed improvement, you can expect a large increase in the weight of the lens and its price tag. More glass is required to make faster lenses, which accounts for the increase in weight and price. Check out the comparison of three 400mm telephoto lenses for cameras with 36 x 24mm sensors in the table below.

	Weight	Diameter x length	Typical price tag
400mm f/5.6	1.25 kg	90 x 256.5 mm	< $2000
400mm f/4	1.95 kg	128 x 233 mm	< $8000
400mm f/2.8	3.85 kg	163 x 343 mm	< $13,000

If lens speed isn’t a prime factor, you can save money, reduce the carrying weight and obtain a telephoto zoom lens, which is likely to be more versatile and, thus, more convenient to use. However, don’t expect a fast lens with focal lengths of 400mm or more in 35mm format.

Third-party lens manufacturers like Tamron and Sigma have enjoyed considerable success with these lenses, with popular products at much lower prices. A few examples are listed below:

Sigma 150-500mm f/5-6.3 APO DG OS HSM lens(above)  sells for approximately $1000 and weighs 1.91 kg.

Sigma 150-600mm F5-6.3 DG OS HSM lens  is priced at roughly $2500. It weighs 2.86 kg and is 290mm long.

 

Tamron SP150-600mm f/5-6.3 Di VC USD lens (above)  weighs 1.95 kg and is 258mm long. It is priced at around $1400.

Photographers who use cameras with smaller sensors can usually find smaller, lighter and cheaper lenses within the 300-600mm (35mm equivalent) focal length range. There aren’t many prime lenses yet, but both Panasonic and Olympus produce zoom lenses that reach the 35mm equivalent focal length of 600mm. Both sell for well under $750, the Panasonic Lumix G Vario 100-300mm f/4-5.6 MEGA OIS lens being slightly shorter and faster than the Olympus M.ZUIKO DIGITAL ED 75″“300mm f/4.8″“6.7 MkII lens. Olympus has a M.ZUIKO DIGITAL ED 300mm f/4 PRO lens under development; it’s scheduled for release later in 2015 but no specifications are available yet.

Even with smaller sensors, fast telephoto lenses are usually relatively large and heavy, as shown in this picture of a M4/3 camera with a 40-150mm f/2.8 zoom lens that covers the equivalent focal length range to 80-300mm in 35mm format. With the tripod mount, this lens weighs 880 grams, roughly double the weight of the camera body. (Source: Olympus.)

Lenses for birding (and other wildlife)

Many wildlife photographers ““ particularly those specialising in bird photography ““ use cameras with smaller sensors, particularly cropped-sensor (APS-C) DSLRs, because they provide a greater ‘reach’ with a telephoto lens. For example, a 300mm lens on an APS-C body will have the same angle of view as a 450mm lens on a ‘full-frame’ Nikon or Sony camera or 480mm on a Canon. The same focal length on a M4/3 camera becomes equivalent to 600mm in 35mm format due to the format’s 2x crop factor.

Because their subjects are usually smaller and often more easily ‘spooked’, bird photographers have tighter requirements than photographers who shoot other wildlife. When shooting from hides, a focal length of at least 300mm (35mm equivalent) is the norm. Wider angles of view may be needed to capture birds in flight.

Cameras with smaller sensors provide an advantage for bird photographers. This shot was taken with a 75-300mm f/4.8-6.7 zoom lens on a M4/3 camera, using the 300mm focal length. The camera’s EVF provided a bright view of the subject to make framing easy, while the background was far enough behind the subject to blur nicely, even with the relatively small f/6.7 maximum aperture.

Lens speed is vital for shooting in low light levels but irrelevant  when working in normal daylight. Zoom lenses can be useful, particularly if they include stabilisation and can focus quickly and accurately.

Teleconverter (extender) lenses are popular with some photographers as a way to magnify subjects with existing lenses. But they reduce the amount of light entering the lens by the magnification factor and can make focusing difficult because the viewfinder becomes dimmer.

Lenses for Sport Photography

Choosing the right lens for photographing sport depends on how close you can get to the action and whether you want close-ups of participants or general views of the scene. Professional sports photographers gain access to the best vantage points at most organised sports. Consequently, when covering sports like football, tennis, basketball and cricket, they can shoot with full frame cameras and use shorter, faster telephoto lenses.

Photo enthusiasts who are forced to shoot from a grandstand can obtain worthwhile close-ups with telephoto lenses, particularly those longer than 400mm (35mm equivalent) ““ provided they use an APS-C or smaller format camera. The list below suggests 35mm equivalent focal lengths that should provide reasonable close-up capabilities for a range of sports when you have to shoot from the grandstand:

Tennis: 70mm to 200mm

Football (all types): 200mm to 300mm

Cricket: 300mm to 400mm

Motor sports: 200mm to 300mm

Baseball: 300mm to 400mm

Fast zoom lenses can be beneficial when shooting indoors, particularly if the aperture remains constant throughout the focal length range. Budget-priced telephoto zooms often have maximum apertures ranging from about f/4 at their shortest focal length to f/5.6 or smaller at maximum zoom.

In normal daylight, this may only present problems if you require a very shallow depth of field to isolate subjects from distracting backgrounds. But it will dim the image in optical viewfinders (but not EVFs) and can require you to use higher ISO settings in poorly-lit venues.

This image was captured with a 70-300mm f/4-5.6 lens on a camera with a 35mm sensor. The 300mm focal length was long enough to provide a close-up view, while the f/5.6 aperture was able to blur the background adequately.

Mirror Lenses

Cash-strapped photographers have known for many years that mirror lenses represent the cheapest way to obtain really long telephoto lenses. But some photographers look down on lenses of this type because of some perceived (and a few real) flaws.

Being relatively small and light, mirror lenses are ideal for photographing wildlife when you have to walk some distance to a suitable location.

On the positive side, mirror lenses have some significant advantages:

1. They are significantly cheaper than conventional telephoto lenses with the same focal lengths.

2. The small physical size and relatively low weight of mirror lenses enables them to be hand-held with an appropriately fast shutter speed (which can be slower with cameras that have sensor-shift stabilisation).

3. Mirror lenses have no mechanical or electronic links with the camera body so you can fit almost any mirror lens to almost any camera body with an appropriate adaptor.

4. The optical design virtually eliminates chromatic aberration.

5. The compact size of the lens makes it inconspicuous, so you don’t get the sort of attention that you would with a conventional telephoto lens.

6. The shallow depth of field makes it easy to isolate subjects from distracting backgrounds.

7. Mirror lenses are free of rectilinear distortion.

An example of the donut effect on out-of-focus highlights created by mirror lenses.

But they also have some noteworthy defects:

1. All mirror lenses (apart from the superseded Sony/Minolta 500mm f/8) are manual focusing and focusing can be tricky as the viewfinder image can be quite dark.

2. The aperture and focal length are fixed so you can’t control depth of field.

3. They are relatively slow, with typical apertures of f/5.6 or f/8.

4. Their overall sharpness can be mediocre.

5. The secondary mirror produces an donut-like effect on out-of-focus highlights.

6. Internal reflections often reduce contrast.

7. Images from all these lenses usually have bright centres with dark corners (vignetting).

This article is an excerpt from Photo Review magazine Issue 64  

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