What lens do I need? A guide to buying your next camera lens

Despite buying cameras which have been specifically designed to take and make use of different lenses, a large number of photographers only ever use the kit lens that their DSLR or interchangeable lens camera came with. But it's really not that surprising, picking the right next lens can be daunting, which is why we're going to try to help with our guide to life after the kit lens.

Lenses are arguably the most important part of your camera set-up, they make or break your pictures. They control the image that's projected onto your imaging sensor, and ultimately what photos you are taking home. As such, many photographers would prefer to shoot with an okay camera and a great lens, than a great camera with ho-hum glass attached. But knowing the importance of good glass is one thing, it's another to know what lens will give you the creative freedom to capture the photos you want to get.

To the uninitiated, lenses are baffling tubes of glass with numbers and confusing acronyms printed on the side. Hopefully, this guide will help you understand which lenses can be used to achieve what, why others can cost more than a family car … and how there are some sub $150 bargains which could change your photography forever.

Which lens should I buy next?

If you currently only have the kit lens your camera came with, the short answer to this question is that as soon as you have the cash available, you should go out and get a fast normal prime lens or a telephoto zoom. The longer and more considered answer is that you need to think about the type of photographs you currently take. You need to understand how different lenses could improve your current photos and allow you to take ones that you currently can't. If that all sounds a bit confusing, read on.

Decoding the lens jargon

The almost sentence-long collection of letters and numbers on the side of a lens barrel can tell you all sorts of things about a lens. But the details which you should probably pay the most attention to are those which detail the focal length, maximum aperture, lens mount and format type.

Focal length

Focal length is expressed in mm and a higher number means a bigger zoom, while a lower number mean the lens can be used for wider shots. As a rough reference, the human eye is said to see about the equivalent of 30-50 mm on a full frame camera (more on that later). A number lower than 30-50 mm will take in a bigger view than you naturally see, while higher numbers mean focus will be on a smaller aspect of your view.

If the lens has a focal length range with two numbers (say 24-80 mm) this means it's a zoom lens and is capable of zooming and being used at any point across that range. However, if there is a single focal length number (50 mm for instance) it's a prime lens, so taking in more or less of the view will require you to get closer or further away from your subject. Traditionally, primes have been considered to be optically superior to zooms, because trade-offs have to be made when producing zoom lenses. But that's not to say that some zooms are not better than some prime lenses.

To make understanding focal length more difficult, the same focal length lens gives different views on cameras with various sensor sizes, because of the crop factor (the sensor only takes up part of the projected image). As a result, many manufactures give a 35 mm-format equivalent on lenses designed for cameras with smaller sensors and in this article descriptions are based on on 35 mm-format. Therefore, if your camera has a smaller sensor, and there's a good chance it does, you'll need to consider this when deciding which lens you need.

If you're using a full frame camera there's no calculation needed, a lens will give you the field of view you'd expect from its number. If your camera has an APS-C sensor (Nikon DX DSLRs, Sony NEX…) it has a crop factor of 1.5 - meaning you multiply the lens focal length by 1.5 to get its equivalent 35 mm-format focal length. For Canon APS-C cameras that number is 1.6, for Micro Four Thirds cameras it's 2.0 and for the Nikon 1 series it's 2.7.

That means a 35 mm lens would give a field of view equivalent to 56 mm on an APS-C camera like a Canon 70D and equivalent to 70 mm on a Micro Four Thirds camera like the Olympus OM-D E-M1. On a Nikon 1 it would act like a 95 mm lens does on a full frame camera.

Maximum Aperture

Maximum Aperture is shown in a number of ways, but whether it's f/2.8 F2.8 or 1:2.8, it all means the same thing and refers to the the maximum amount of light which the lens can gather. Lenses with larger maximum apertures (slightly confusingly these are the ones with lower numbers) are capable of gathering more light.

As a F1.8 lens is able to use more light than an F4 lens, this means it could be used in lower-light situations without having to use a flash, and is capable of producing a shallower depth of field (the part of the image that is sharp) as shown below.

Some zoom lenses have a variable maximum aperture meaning that it changes depending on focal length. So, while a 18-200 mm F3.5-5.6 lens would have a maximum aperture of F3.5 at 18 mm, it would be be F5.6 by the time you zoomed to 200 mm.

Lens Mount

It goes without saying that you want to buy a lens that will attach on your camera, and this is known as the lens mount. Camera manufacturers generally make lenses with proprietry mounts which will only fit their devices, sometimes having multiple lens mounts for different camera lines. The major exception to this is Micro Four Thirds lenses which can be used on respective Olympus and Panasonic cameras. Third party manufacturers also make lenses with mounts to fit various brands.

It's important to know which mount your camera uses before heading out to buy a lens. Example lens mounts for DSLRs include the Nikon F-mount, Canon's EF or EF-S, the Pentax K and Sony's Alpha (A) mount. For mirrorless interchangeable lens cameras, these are things like the Canon EF-M, Fujifilm XF, Nikon 1, Sony E, Samsung NX and Pentax Q. As mentioned earlier, Olympus and Panasonic Micro Four Thirds cameras take any Micro Four Thirds mount lenses.

Format

In addition to being able to mount the lens on your camera, you need to be sure it will produce an image big enough to cover the image sensor. Because different cameras use different size sensors, manufacturers produce specific lenses to work with them.

For example, while Nikon DSLRs come with full frame or APS-C sensors - and both take F-mount lenses - its DX lenses only produce an image big enough to cover the smaller of the two sensors. Meanwhile, FX lenses cover the full frame and can also be used on DX and even Nikon 1 cameras (with an adapter). This is done because lenses designed for smaller sensors can be physically smaller and lighter themselves.

Different types of lens

Lenses are generally categorized by their focal range or specific function if they're a specialist lens. Below we've taken a look at a few of the most common types of lens, thought about the characteristics their images are said to have, and considered how they can be used.

Ultra Wide

What they are: Ultra Wide angle lenses have a focal length of around less than 24 mm (in 35 mm-format), this means they can take in a wider scene than is typical, though they're not only about getting all of a subject into a shot. Rectilinear ultra wides help keep straight lines, just that, while fisheyes will reproduce buildings with curved walls.

Image characteristics: Because of the wide field of view, shots with ultra wide angle lenses typically feature a large depth of field. Images tend to pull in subjects that are close, and push away more distant ones making them appear further apart. Perspective distortion of ultra wides can give falling-building-syndrome (where vertical lines converge) but this can be corrected in post-processing, or minimized with good technique.

What they are used for: While often seen as a specialist lens, ultra wide angles can be used in a number of ways. Typical uses include landscape, architecture and interior photography. Even the distortion can be used creatively, especially when using fisheye lenses.

Wide Angle

What they are: Typically covering a focal length between 24 mm and 35 mm, Wide Angle lenses are available as primes or zooms and come with either variable or fixed maximum aperture. Offering a wide field of view, they often also boast close minimum focusing distances.

Image characteristics: Wide angle photographs can magnify the perceived distance between subjects in the foreground and background. Wide angles suffer less distortion than their ultra wide counterparts, but you still get an exaggeration of lines and curves which can be used artistically.

What they are used for: Many people only reach for a wide angle lens when trying to get the whole of a subject in frame, whether that's a building, a large group of people or a landscape. However, while those are perfectly good uses of one, they can also be used for interesting portraits where you want to place a subject in a situation. Just be careful not to distort faces unflatteringly by shooting too close.

Standard / Normal

What the are: The kit lens your DSLR or interchangeable lens mirrorless camera came with is probably an example of a standard zoom lens, covering a focal range of around 35-70 mm. Ones with better optics and faster maximum apertures are also available. Many photographers consider a 50 mm prime (in 35-mm-format) as a normal lens, as it's said to reproduce an image with a angle of view which feels "natural" and similar to what you see with your eyes - even thought this isn't technically true.

Image characteristics: Standard zoom lenses and normal primes sit between wide angles and telephotos in terms of image characteristics and are much more like you see with the human eye. Normal prime lenses tend to have faster maximum apertures which can allow for a shallow depth of field and lower light shooting.

What they are used for: As their name would suggest, normal or standard lenses are versatile lenses which can be used for almost all sorts of photography whether street, documentary, landscape, or portrait. Because normal prime lenses tend to feature faster maximum apertures, they allow you to shoot with a shallower depth of field and in lower light.

Telephoto

What they are: Telephoto lenses are those with a focal length in excess of 70 mm, though many people would argue that "true" telephoto lenses are ones which exceed 135 mm. They focus on a much narrower field of view than other lenses, which means they are good for focusing in on specific details or distant subjects. They are generally larger and heavier than equally specified wider lenses.

Image characteristics: Because they have a narrower angle of view, telephoto lenses bring far away subjects closer. They can also have the effect of compressing the sense of distance in a scene and making objects appear closer together. A narrow depth of field means that a subject can be in focus with a blurred background and foreground.

What they are used for: In addition to being used to photograph subjects you can't (or don't want to) get close to - like sports or wildlife - telephoto lenses can be used for shooting portraits and even landscapes where their normalization of relative size can be used to give a sense of scale.

Superzoom

What they are: Superzooms are do-it-all lenses which cover focal lengths from wide to telephoto. They can be good for uses in situations where you can't or don't want to be changing lenses and they normally change in length as you zoom.

Image characteristics: Because compromises have had to be made producing a do-it-all lens, superzooms do not have the same image quality of more dedicated lenses and often have slower and variable maximum apertures.

What they are used for: Offering a one-lens package, superzooms come into their own if you can't (or don't want to) change lenses. This could be when in situations where it wouldn't be safe to switch lenses, or when travelling - you don't necessarily want to be weighed down by five lenses when on holiday with the family.

Macro

What they are: One of the more specialist lenses, marco lenses are technically those which are capable of reproduction ratios greater than 1:1. However, the term is frequently used to refer to any lens which can be used for extreme close-up photography. Macro lenses typically have focal lengths somewhere between 40-200 mm.

Image characteristics: Macro lenses normally have excellent image sharpness, though it's worth noting that when working at close distances they also have a tiny depth of field. You can often end up with a shot of an insect where only a fraction of it is in focus.

What they are used for: Though normally used for close-up photography (at which they excel), macro lenses can also be great for portraits thanks to their typical sharpness and focal lengths.

Other things to consider

Size, weight … and price

With changes in focal length and maximum aperture come another set of lens changes, namely size, weight and price. Ideally we'd all be wielding a 16-600 mm F1.8 lens. Unfortunately, not only does physics dictate that such a lens would need to be huge and very heavy, it would also cost a fortune to produce, if it was even possible.

As such, any lens is going to make compromises to fit into a package of a size and weight which suits its users. Extreme focal lengths and larger apertures mean bigger and heavier lenses, which along with the bigger price-tags is why they are typically used by professionals who can justify purchasing them.

Image stabilization, build quality and video

There are a number of other features which you may want think about, regarding your next lens. Image stabilization allows for use of slower shutter speeds without suffering camera shake (though some brands incorporate this into camera bodies rather than the lens). Stabilization is also very handy if you're shooting lots of video, in which case you might also want to think about lenses with power zooms which can zoom at adjustable speeds.

Weather-sealing means you can use your lens (assuming your camera is equally weather-sealed) in extreme weather conditions and normally also means a higher level of build quality.

Other considerations include the use of special lens elements and coatings which can improve sharpness and reduce image problems such as chromatic aberration. It's also worth thinking about whether you would benefit from a higher number of aperture blades which can give a more pleasing bokeh, and if you need lenses with internal focus motors, or indeed only manual focus.

Third party manufacturers

While the majority of photographers buy lenses from the same firm as their camera, there are a number of third party manufacturers such as Sigma, Tamron and Tokina which produce lenses for DSLRs and mirrorless interchangeable lens cameras. Traditionally seen as a less desirable option, some of the newer third party lenses are as good if not better than their Canon/Nikon/Sony counterparts. They are often also considerably cheaper.

Examples of what lens to buy

Below are a number of typical situations that kit-lens-toting photographers often find themselves in. For each example, we've highlighted some of the factors that should be considered when trying to find the right lens for the job. While these are factors which are relevant whatever camera and lens system you're using, in each case we've also highlighted a couple of lenses that would be a good choice for specific set-ups without blowing the budget.

I want an all-day / travel lens

When you're on holiday or traveling, you probably don't want to be lugging several lenses and cameras around with you – unless you're the most dedicated of photographers, that is. It's often the same if you're trying to enjoy a day with the family and don't want to spend all day changing lenses and moaning about your back.

As such, a good all-day or travel lens would be one that was easy enough to carry around, but still offered you the freedom to capture shots from landscapes to portraits, and zoom in on distant objects. For Micro Four Thirds shooters, that could be something like the Panasonic Lumix G Vario 14-140 mm f/3.5-5.6, or the AF-S DX NIKKOR 18-200 mm f/3.5-5.6G ED VR II if a DX Nikon is your DSLR or choice.

I want to do street photography

Street photography can be done with almost any lens, though a 300 mm F2.8 might raise a few eyebrows from your subjects. However, a focal range of around 35-50 mm is often seen as the ideal for capturing the moment in urban areas.

Unless you want all of your subjects looking directly at the camera, you'd probably be best served by something discrete. It's also important that street photography lenses feature a fast maximum aperture for lower-light situations. This means that something like the Fuji XF 23 mm f1.4 R Lens would be a great selection. The Sigma 35 mm F1.4 DG HSM has also been very well received by many DSLR street shooters.

I struggle to photograph my kids running around in the garden

Many people shell out for a DSLR or mirrorless interchangeable lens camera when they have a child, but by the time that child starts running around, the kit lens struggles to keep up, both in terms of aperture and focal range. This is especially true if you're trying to photograph the kids running around in the garden or on the sports field.

This means you need something with a bit more reach, but probably without the bulk and weight that a professional lens would bring. A zoom lens will allow you to keep your shots framed as you want while your subject moves around in front of you. So, if you feel you just need some added reach, the EF-S 55-250 mm f/4-5.6 IS II could get you closer to the action. But if you want a bit more speed (and to be the best equipped parent at the game), there's the Canon EF 70-200 mm f/4L USM.

I want to take landscape photographs

While the kit lenses which come with most cameras are surprisingly good at the wide angle end, you could find that they don't quite go far enough for some of the landscape images you try to take. So, unless you're able to keep moving backwards, you're going to need a new lens.

Focal length is key here, and you'll only get some landscapes if you've got an ultra wide angle lens. You could go for either a prime or a zoom, but most people in this situation are probably going to be best-served by a zoom. A lens like the AF-S DX NIKKOR 10-24 mm f/3.5-4.5G ED could be good for APS-C Nikon shooters, while the Olympus 9-18 mm f/4-5.6 ZUIKO would do the job on Micro Four Thirds cameras.

I want a lens which will make me improve as a photographer

After a while you might find that you've simply outgrown your kit lens. You suddenly find that it's stifling your creative ambitions and preventing you from taking the photos that you want, even if they are within its focal length reach.

This is the ideal time to get yourself a fast prime lens, and the good news is that you don't have to spend a fortune to do it. Getting something like a Nikon AF-S DX NIKKOR 35 mm f/1.8G or the Sony E 50 mm f/1.8 OSS will mean you can play around with shallower depths of field, and shoot naturally in conditions that would have otherwise required a flash. Because they are primes, it also means you need to zoom with your feet, which will in turn probably mean you spend more time thinking about how you compose shots. Never a bad thing.

Summary

As we've seen, different lenses can give photographers the creative freedom to take all sorts of images. It's no understatement to say they are as important, if not more so, than the camera you're using. This is why it's such a shame to see photographers buy cameras with the ability to change lenses and then never do so.

It's worth remembering that lenses can often last longer than your camera, because they will continue to work on the next generation of cameras, and the one after that, probably. This is why many photographers are willing to spend more on an individual lens than their camera.

However, buying new lenses doesn't have to mean spending a fortune. We've seen how relatively inexpensive primes like the nifty-fifty (50 mm F1.8) can change your photography forever. There are also thousands of second-hand lenses which will work just as well as new ones out there – especially for DSLR shooters, where you can often use a 20-year-old lens. You never know, your father might even have some lying around in the attic.

Hopefully this article hasn't made you feel compelled to buy more and more lenses, as that really wasn't the aim. If you're not sure if you need a new lens, you probably don't. Instead, we hope this has helped you understand what to look for when you feel that your current lenses are preventing you from being the photographer you want to be.