If you're the owner of a new digital SLR or mirrorless camera you can improve your photography instantly by using different photo lenses.

However, while there's an almost endless supply of options to buy, it isn't always obvious what lens to use to get the shot you want.

Here are five common camera lenses, what they're good for, and when you should use them.

What Lens to Use: The Basics

Before we get into the different kinds of photo lenses, it pays to know a bit about what makes them so different.

Lenses are differentiated by their focal length, which shows how wide or zoomed-in they are. The focal length is measured in millimeters, and is either a fixed length, like 35mm, or a zoom range like 50-200mm.

The focal length is essentially the zoom level of the lens. A 300mm lens will make far-away subjects appear a lot closer than a 24mm lens. You can use a lens simulator to get a feel for what different focal lengths look like.

Although it's not an exact calculation, the equivalent focal length to what the human eye can perceive is about 50mm on a full-frame camera, or 27mm on an APS-C sensor. This means that what you can see through a lens at this focal length is approximately what you'd see if you were looking at the scene with a naked eye.

It's important to remember that the size of the sensor of your camera can make a big difference in actual focal length. Some lenses include "adjusted" focal lengths, but if they don't, you can use this handy lens multiplication factor calculator from Digified.net.

1. Wide-Angle Lens

In the simplest terms, a wide-angle lens has a larger field of view that allows you to fit more into the frame.

A typical wide-angle lens has a focal length of 24-35mm on a full frame sensor, or around 16-24mm on a crop sensor. Ultra wide-angle lenses, which capture even more of a scene, have very short focal lengths of 24mm or less.

wide angle foreground

Wide-angle lenses can be tricky to master at first. They give an image an exaggerated sense of depth, pulling the foreground forward and pushing the background back.

For this reason, you should always try to have an object in the foreground to anchor the image (and something in the middle ground and background, too, to make the most of that depth).

wide angle distortion

A wide-angle lens can also distort straight lines. They can make the horizon look curved, or if you tilt the camera can make vertical lines point inwards. Camera software will sometimes correct for this, but you can also harness it to create some cool effects.

So what exactly is a 24mm or wider lens good for?

wide angle lens

The wider field of view means you can fit more into the frame, so it's great for landscapes, astrophotography, and architecture shots. The increased depth in the image is perfect for shooting interiors---a wide-angle lens can make a small room appear much larger.

These lenses are also good for general street shooting as they make it easy to capture subjects in context with their environment.

2. Kit Lens

When you bought a DSLR or an interchangeable-lens camera it almost certainly came with a standard "kit" lens. These zoom lenses are very versatile, and have focal lengths between 35 and 70mm on a full frame sensor, or typically 18-55mm on a crop sensor.

A kit lens is flexible and easy to use because it covers the most common focal lengths. It goes from a moderate wide-angle to a moderate telephoto, and is good for anything.

kit lens

A kit lens is intended for general use, whether you're going for landscapes, portraits, action photos, urban shoots, whatever. They work best for subjects at a close-to-medium distance, when you don't need to zoom in on something far away or get super close to a small object.

These lenses are highly versatile, which is why most cameras come with one.

One of the best times to use a kit lens is when you're travelling. Because it's such a well-rounded lens, you can use it on its own, or perhaps with just one other lens in your camera bag.

3. Telephoto and Superzoom Lenses

If you need a camera lens for far away shots, you need a telephoto or superzoom lens.

Telephoto lenses have a fixed focal length starting at around 70mm. Superzooms---as the name implies---are zoom lenses that cover a range of focal lengths. A popular second lens choice for many is a 55-200mm superzoom.

They go longer still---you can get lenses over 5000mm if you really want one---but these are often incredibly expensive, running into the thousands of dollars. They're also the biggest and heaviest lenses.

So what are telephoto and superzoom lenses, like a 70-300mm, used for? They're best when you want to get close to a distant subject. It could be a building on the horizon or a face in a crowd. They're perfect for wildlife photography, where you can't get close to the animals you want to shoot.

telephoto lens

Your subject doesn't have to be really far away. If you're trying to craft an image where the subject fills the entire frame, a telephoto or superzoom can help you get a picture that makes the viewer feel very close to the subject.

Shorter telephoto lenses can be great for portraits, as they tend to make your subject really stand out from the background of the photo.

4. Macro Lenses

Macro lenses are specialized lenses that excel at close-up photography. Many of them produce a 1:1 image, which means they capture your subject at life-size. It allows for crazy levels of detail.

macro lens

You can use a macro lens to shoot flowers, insects, and other small objects, though they're suited to other situations as well.

Coins, old mechanical parts, wood, and everyday mundane objects like your keys or a glass of water can become huge landscapes with textures and patterns that you never noticed before.

Macro lenses also excel at creating images with a shallow depth of field, leaving only the foreground in focus, as in the image above.

5. Prime Lenses

Prime lenses are on the list of essential gear every photographer should own. A prime lens is the opposite of a zoom lens: it has a single focal length. You can get prime lenses in any length, from ultra wide-angle to telephoto.

With the ready availability of zoom lenses in any focal length, it might seem like a technological step backward to use a prime lens, but there are some distinct advantages.

Prime lenses have fewer moving parts, so are very often higher quality than zooms at the same focal length. This makes them popular for portraiture.

prime lens low light

Another big advantage is that they often have faster apertures, meaning that they can capture better images in low-light situations, making them good for night and sports photography.

A fast aperture also means you can shoot with a shallower depth of field, giving your images a nice bokeh---a soft, creamy background.

prime lens portrait

And, of course, no moving parts means that they can be quite a bit cheaper than zoom lenses, not to mention smaller.

When should you use a prime lens? Anytime you want to get a sharp, high-quality picture. Traditional uses for primes include portraits, night photos, and action shots. You can get them in every focal length, though, so you can find a prime lens for any type of photography that you're interested in.

50mm "nifty fifty" primes are great all-around lenses. Professional photographers often use 58mm lenses on a crop sensor---around 85mm on full frame---to shoot portraits.

What Camera Lens to Use

It's a good idea to keep a few lenses in your camera bag so that you can cover as many different focal lengths as possible. A wide prime lens, a kit lens, and a superzoom make for a good starting point.

Ultimately, though, you need to match the lens to the type of the photo you want to take. Our guide to the best camera lenses for different type of photography has got everything you need to get started.

And don't forget that you can use lenses even if you're mostly a smartphone photographer. See our list of the best smartphone camera lenses to see our recommendations.