Why do I need another lens?

So you’ve just bought your first interchangeable lens camera? That’s excellent. Whichever camera you’ve bought, it’s likely to be able to support you in taking some great photos. Your camera probably already came with a lens and it’s likely to be totally fine, so why would you need to buy more?

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Essentially, the different lenses can extend the kinds of photographs you’re able to take. Different lenses can allow you to take better photographs of different subjects or in different circumstances. It’s all a question of what you want to shoot.

What are the options?

At first glance, looking at additional lenses can be daunting: there are lots of options, their names appear to be written in an obscure code and it’ll quickly become apparent that seemingly small changes in these numbers can equate to a vast difference in price.

An important thing to remember is that you don’t need a ‘complete’ set. So don’t worry about that huge pile of lenses that probably appears on the camera maker’s website or in the back of the sales catalogue; you’re not going to need to buy them all.

You don't need to collect them all. Most people will only benefit from having a couple of these lenses. The question is: 'which ones are right for you?'
Image courtesy of Canon

Your specific interests and photographic style will dictate which lenses you need (or, at least, want). And, though there’s always some risk that your photography gets shaped by which lenses you have and haven’t got, there’s nothing that says you need lots of lenses to achieve everything you want to achieve.

The effect of focal length (and aperture) depends on the sensor size you mount it in front of. We're only going to discuss general classes of lenses in this articles, not specific examples.

The two main properties of a lens are its focal length/s (which defines the view of the world it gives) and the maximum aperture value/s (which defines how much light it can let in). Here's what different focal lengths look like on a Full Frame camera, shot from the same position:

21mm 24mm 28mm 35mm 50mm 85mm 100mm 200mm

Prime and zoom lenses

Most common lenses, including the ‘kit’ zoom that probably came bundled with your camera are zoom lenses. These have complex mechanisms that allow them to offer a range of focal lengths, meaning they can be zoomed in and out to change the magnification of your subject and what you include or exclude from your image. Zooms are highly flexible.

A zoom lens will list the widest and longest focal lengths it offers (eg 18-55mm), and will also list how wide and bright the aperture can go, first at the widest focal length, then at the longest (eg F3.5-5.6), the lower the number, the more light it can let in.

The alternative to zooms are prime lenses. These only offer a single focal length: the lens can’t been zoomed in or out. Why would anyone want such a restrictive lens? From a practical perspective, it’s easier to design a prime lens with good optical performance and a bright maximum aperture, to let in lots of light, since the design only has to do one thing. And, from a creative perspective, many photographers find a prime lens forces them to consider the composition of their images more carefully.

What’s a telephoto lens?

Although the term has a specific meaning, most people use ‘telephoto’ lens to mean anything longer than about 50mm equivalent. Essentially, anything significantly more ‘zoomed-in’ than looking at the world with the naked eye.

Telephoto lenses with long focal lengths can make your photos seem closer to the action, so they lend themselves particularly well to wildlife and sports photography.

Many camera brands offer a telephoto zoom lens that can be bought as part of a ‘twin lens kit’ when you buy the camera. Like your standard kit zoom, this is likely to be an F3.5-5.6 variable aperture lens. Like your kit zoom, this will be perfectly effective in a lot of situations but won’t necessarily be the sharpest lens or the most effective as the light starts to fall.

A short to moderate telephoto lens can be perfect for portrait shooting.
Photo by Dan Bracaglia

Telephoto lenses can be used for all sorts of things. Short to moderate tele lenses are great for portraiture, allowing you to stand a sensible distance from your subject while including your subjects head or head and shoulders. Longer telephoto lenses can be ideal for various types of sports shooting, and super-long telephotos tend to be specialist lenses for birding.

If your budget will stretch to it, the best quality telephoto zooms tend to be the ‘constant aperture’ models, which maintain the same F-number throughout their zoom range. 

If you find that the long end of your kit zoom doesn’t get you close enough to the action, it’s worth looking into a telephoto lens.

What’s a wide-angle lens?

As you can probably deduce, wide-angle lenses are the opposite of telephotos: they are lenses with short focal length that offers a wider view than you see with the naked eye.

Wide-angle lenses let you capture a wide field-of-view, making them ideal for landscape work or shots that give a dramatic perspective on the world.

These lenses can be used for all sorts of landscape and environmental photography and can lend a dramatic effect to your images. If you often find yourself shooting at the widest setting on your kit zoom and backing away from your subject, you might find a wide-angle lens is a good first choice.

What’s a macro lens?

Macro lenses are specialist lenses that are designed so that they can focus very close-up, enabling high magnification photography. These are especially popular with photographers who want to shoot insects, flowers and other small, fine detail.

Macro lenses allow you to shoot small objects close-up.
Photo: Wenmei Hill

If your kit zoom refuses to focus and your chosen subject always ends up looking tiny in the frame, it might be worth looking more closely at a macro lens.

What about your kit zoom?

A common mistake is to assume that because you already have a zoom that covers the moderate-wide to moderate-tele range, there’s no need to buy a new lens in this range. Actually, the opposite may be true.

Kit zooms let you to go out shooting, the moment you open the camera box but they're often built to very low cost. This can mean patchy optical performance and slow maximum apertures that can limit your camera's low light capability and little opportunity to shoot with shallow depth-of-field.

The prime lens used here gives more ability to blur the background than the zoom lens that comes kitted with most cameras.

For many people, the ‘normal’ range covered by the kit lens ends up including the focal lengths that are most often useful, so there’s an argument for buying a better lens to replace or augment your kit zoom. For instance, many companies make relatively inexpensive prime lenses in this region that have a brighter maximum aperture than the kit lens. These can provide a first taste of shallow depth-of-field and are ideal for low light work. 

'Normal' lenses shows approximately the view you see with the naked eye: neither zoomed-in nor zoomed-out. They're great for capturing the world around you, so you may find it makes sense to buy a sharper or brighter lens even if it overlaps with your kit zoom.
Photo by Dan Bracaglia

Alternatively, companies such as Sigma, Tamron and Tokina make constant F2.8 zooms that are often sharper and more versatile than the lens that came in the box.

Get out there and try it

If you’re worried about whether you’ll find it useful, try renting a copy before you buy. Alternatively, search around for second-hand options (though this often entails doing increased research to ensure no nasty compatibility surprises).

Whichever choice you make, it can take some time to adjust your minds-eye to ‘see’ the photos that your new lens will let you take. Give it some time, keep shooting with it and you’ll find you start to get an almost instinctive feel for a new angle-of-view.

And, even if you change your mind, a good lens will tend to retain a good portion of its value if you look after it, so you can always sell up and try again, if your mood or style changes.