Whether you’ve got an entry-level camera or a professional DSLR, your camera is nothing without a lens. Photography, by its very nature, requires light in order to generate an image, and your lens is the means by which your camera gathers that necessary light.

While contemporary compact digital cameras and ‘bridge’ or ‘superzoom’ cameras are improving their fixed optics all the time, a digital SLR offers you the option of choosing which lenses suit your individual shooting requirements, with an ever-increasing list of options unfolding.

A photographic lens is made up of several lens elements, arranged inside a barrel, that move in order to focus beams of light onto your digital camera’s sensor. A diaphragm – much like the iris in a human eye – grows larger or smaller according to the aperture that you set, and subsequently allows more or less light to reach the sensor. The performance of a lens depends largely on the type and quality of the components used in its construction. More expensive lenses include elements made from higher grade glass, while cheaper lenses comprise lower-grade materials. Pricier optics also tend to offer more advanced forms of technology, from silent motors and internal focusing mechanisms to gyros that combat camera shake and extra low-dispersion glass, producing sharper images with less distortion.

The focal length of a lens determines your angle of view – ie, how much of the scene will be recorded in a single frame – and the maximum aperture affects the light-gathering ability of the lens. Expressed as an ‘f-number’, the maximum aperture indicates how wide you can open up the diaphragm. A lens with a maximum aperture of f2.8 for example, is described as a ‘faster’ lens that can gather far more light than an equivalent lens with a maximum aperture of, say, f5.6.

Faster lenses are generally more expensive and produce higher quality, sharper images.
This guide aims to help you make a more informed decision when shopping for optics.

The basics
• Prime lenses have a fixed focal length and do not zoom. Because of this, they’re very well engineered, fast and produce high-quality images.

• Zoom lenses offer greater versatility and cut down the number of lenses you need to carry around, but they do tend to suffer more distortion than primes.

• Telephoto lenses are used widely by sports photographers and the paparazzi and as they enable the user to get close-up shots from a long distance.

• Wide-angle lenses are ideal for capturing vast scenes, from landscapes to panoramas and group shots.

• Generally, when shopping for optics, you get what you pay for. Lenses can be very expensive, but should stand the test of time and don’t depreciate in the same way as DSLR bodies do.


Prime versus Zoom
Prime lenses remain at a constant focal length, the ‘standard’ length being 50mm. They can be engineered with greater precision than zoom lenses, as the manufacturer only has to design them with one focal length in mind. Primes tend to have large maximum apertures, making them ‘fast’ lenses that are very efficient at light gathering. For this reason, this type of lens tends to be used by photographers who demand the crispest image quality.

Zoom lenses, on the other hand, are very versatile, covering a range of focal lengths. They are also a good option if you want to keep the weight of your kit bag down, or if you’re working in surroundings where it could be detrimental to your camera if you constantly have to change lenses – for example, in a dusty environment.
The downside is that zoom lenses are slower than primes, offering smaller maximum apertures.

They also suffer more acutely from chromatic aberrations and distortion at some focal lengths, due to the complexity of the mechanisms required to shift the elements within the lens barrel along with the grade of the glass used to manufacture them.

When deciding whether to opt for a prime or zoom lens, you need to take into consideration what you’re going to be doing with your images and at what level. If you’re an enthusiast who wants to create some prints at home or enter some competitions for example, a good quality zoom lens from a reliable manufacturer can generate excellent results. If you’re a professional user, or you want to produce images of superior quality in order to sell them, then a prime lens might be worth considering instead.

Macro
The world of macro photography can be fascinating, allowing insight into a hidden world that we would otherwise never witness. It’s also an opportunity to create some really weird and wonderful photos, allowing you to transform familiar, everyday objects into alien abstracts and uncover details in items that you never knew existed.

Those of you who’ve looked at objects under a microscope will appreciate just how many secrets Mother Nature conceals from the naked human eye and how fascinating it is to explore them. Macro photography allows us to look into this unseen world and reveal the hidden beauty of even the most mundane objects.

When taking macro photographs, remember that you’re not only magnifying your subject, but also any possible mistakes. For this reason you will need to make sure you have the right conditions and equipment to get it just right. You need a lot of light to take a good, crisp macro photograph, so it makes sense to go for a fast lens and – if you’re a serious macro photographer – you may want to invest in some specialist lighting equipment, like the Nikon R1C1 Creative Lighting System. A tripod is also a must-have accessory to combat camera shake and keep things as steady as possible.

Macro lenses can focus very close, allowing you to fill the frame with your subject. Lenses in the 50–60mm range are usually best for product photography and small objects. The 90–105mm range is popular for some insects and flowers, while the 150–200mm range allows you to work further away from your subject, making it an ideal choice for more nervous or delicate insects and small animals.

Wide-angle
A lens with a focal length below the standard 50mm is classified as a wide-angle lens. Such lenses offer a wide angle of view, making them ideal for taking photographs of sweeping landscapes or tall trees and buildings.

The world of wide-angle lenses is broken down into several sub-categories of lens, namely super or wide-angle and fisheye lenses. 35mm, 28mm and 24mm focal lengths are classified as wide-angle, 20mm to around 13mm are super wide-angle and anything below that falls into the fisheye category.

Wide-angle lenses deliver a large depth of field, making them great for situations where you want to keep the foreground and background in sharp focus. They also make great tools when working in tight spaces and are excellent for photographing the interior of buildings. The one drawback is that they are prone to distortion, ‘bending’ objects at the edges of the frame in wide vistas or making close objects seem enlarged and misshapen. This makes them less-than-ideal for taking flattering portraits, but the effect they create can be used to creative effect.

Emphasise a person’s height by shooting them from ground level with a wide-angle lens, or photograph them from above and their forehead becomes bulbous and enlarged: not exactly complimentary, but excellent for creating humour.

Wide-angle lenses are versatile tools that can be put to good use in a variety of situations. They do vary in terms of the image quality they produce, so if you want top-notch performance, you’ll need to make a greater investment.

Telephoto
Telephoto lenses deliver a narrower angle of view than a standard lens, magnifying and compressing distant objects and throwing close subjects out of focus. They also deliver a shallower depth of field in order to separate the main subject from the background, making them the top choice of sports photographers, paparazzi and photojournalists.

Telephoto lenses allow you to get a closer look at your subject, without having to physically move closer. This makes them particularly useful for nature photography, where it’s obviously important not to alert your subject to your presence. These lenses are also handy for fans of candid portraiture, as they allow you to capture more natural shots of people who are unaware that they are being photographed, such as at weddings or for street photography.You can also use telephoto lenses to isolate certain patterns or objects in a busy scene, making your subject fill the frame and excluding unwanted elements.

Due to the shallow depth of field created when using these lenses, you need to be careful when focusing on your subject, ensuring that your point of interest is sharp, rather than some random element in the background. Telephoto lenses are also particularly susceptible to the effects of camera shake – the longer the focal length, the more apparent any movement will be, making it important to take steps to ensure your camera and lens stay still. Always try to shoot with a tripod or use some other stable structure to support your lens.

Faster telephoto lenses allow a little room for error, and some lenses include technology that counteracts movements made by the photographer, increasing your chances of getting a sharp shot further still.

Optical Image Stabilisation
Lenses with long focal lengths are more prone to the effects of camera shake: a problem that manufacturers compensate for by including the technology to combat it. Every manufacturer has a name for their own version of this technology: Canon call it Image Stabilisation (IS), Nikon has Vibration Reduction (VR), Leica call it MegaOIS and Pentax label theirs as Shake Reduction (SR).
Camera shake is counteracted through the use of a floating lens element and a set of gyros that detect movement and move the element to compensate, resulting in sharper, shake-free images at slower shutter speeds than is possible
when shooting handheld with a more basic type
of lens.

Optical Image Stabilisation technology is highly useful when shooting moving subjects in low light, but it comes at a price and is usually only found in high-end lenses.

Buying guide

The lowdown on the cream of the optical crop

PRIME vs ZOOM

Canon EF 50 mm f1.8II
Price: £90
Where to buy: www.canon.co.uk
Comment: An incredibly compact, lightweight lens that offers a 46-degree diagonal angle of view. Gaussian optics deliver a
high standard of image quality and excellent sharpness.

Sigma 50-500mm f4-6.3 EX DG HSM
Price: £900
Where to buy: www.sigma-imaging-uk.com
Comment: This lens from Sigma covers a colossal focal range, meaning you don’t need to lug around any other lenses. It’s not small or light, but it is fast and quiet.

MACRO

105mm f2.8G AF-S VR Micro-Nikkor
Price: £600
Where to buy: www.nikon.co.uk
Comment: This lens incorporates Vibration Reduction (VR) technology to reduce the effects
of camera shake, making it ideal for macro photography.

Sigma 70mm f2.8 EX DG Macro
Price: £460
Where to buy: www.tamron.com
Comment: Judged Best Expert Lens at the TIPA Awards 2007, this comprehensive lens is an ideal choice for 1:1 macro photography.

WIDE-ANGLE

Tamron SP AF 11-18mm f4.5-5.6 Di II LD Aspherical [IF]
Price: £460
Where to buy: www.tamron.com
Comment: A super wide-angle zoom lens designed exclusively for DSLRs with sensors smaller than full-frame
and available in Canon, Nikon and Sony mounts.

17-35mm f2.8D ED-IF AF-S Zoom-Nikkor
Price: £999
Where to buy: www.nikon.co.uk
Comment: This highly portable ultra wide-angle lens is a versatile option for photographers on a budget and incorporates a Silent Wave Motor (SWM) for quick, quiet focusing.

TELEPHOTO

70-200mm f2.8G ED-IF AF-S VR Zoom-Nikkor
Price: £1,450
Where to buy: www.nikon.co.uk
Comment: IF and AF-S make this lens super-quick and whisper-quiet, while
the VR does a great job of eliminating camera shake. It’s very expensive, but quality like this doesn’t come cheap.

Canon EF 55-200mm f4.5-5.6 II USM
Price: £230
Where to buy: www.canon.co.uk
Comment: An economical, compact and lightweight telephoto zoom that utilises a Silent Wave Motor for quiet,
fast focusing.