Camera Lens Focal Length Explained

3 December 2021

It’s easy to be a little daunted when it comes to choosing a lens for your camera. The different sizes, weight and numbers associated with camera lenses can become overwhelming, but understanding what focal length is and what it does, will better help you decide the best lens for your type of photography. Here’s a guide to focal length, explained simply.

Why your choice of focal length matters

Many beginners put a lot of their focus on choosing the right camera body, but the lens you choose has a huge influence on the final look of your image. Not only is the lens (or glass, as it's sometimes referred to) responsible for bending and shaping the light, but it's also responsible for the field of view you’ll see through the finder.

Before you purchase any lens, think about the type of photography you want to achieve and the attributes you will require:

  • Will you have several different lenses in your kit, or would you rather have one versatile lens?
  • Is the weight of your lens a factor?
  • Will you be shooting people, plants, animals, buildings or landscapes?
  • Can you get up close and personal to your subject or will you need to keep a distance?
Focal Length ExplainedFocal Length Explained

Knowing these factors will help you better understand the role focal lengths play in your photography and help you work out which type of lens is the most useful for. To help you select the best camera lens for your needs, we put together a camera lens buying guide.

What is the focal length of a lens?

Camera Lens Focal Length ExplainedCamera Lens Focal Length Explained

Put simply, a focal length is the measurement of a lens attributed in mm. Often people mistakenly think that this measurement refers to the physical length of the lens. It actually refers to the angle of view of the lens when focused to infinity. This dictates how magnified your subjects will be when using the lens and how far away from your subject you can be for optimum use.

A shorter focal length is presented by a smaller number, such as 16mm. This will provide you with a wider field of view more commonly used when you want to get more into your photographs, like landscapes for instance. A longer focal length, such as 400mm, provides a much narrower field of view and is used to zoom in on something such as an animal or a person or object far away.

Zoom vs. Prime lenses: which one is right for me?

There are two different types of lenses, regardless of their focal length; zoom lenses and prime lenses. Zoom lenses can change focal length. You may have seen a lens that extends or contracts when twisting it on the camera enabling the user to zoom out or zoom in on their subject. A 24-70mm zoom lens operates at 24 at its widest and at 70mm focal length at its most zoomed in. It affords flexibility without having to change lenses, which makes them the best camera lens for travel, as you only need one zoom lens in your kit to cover all your bases.

Camera Lens Focal Length ExplainedCamera Lens Focal Length Explained

A prime lens is a fixed lens in that its focal length cannot be changed. You need to change lenses to adjust the focal length. Prime lenses most commonly come in the 35mm, 50mm and 85mm varieties. Prime lenses are not as versatile as zoom lenses but they usually provide superior optical and low-light performance, at a lower price point.

Different focal lengths and their uses

Camera Lens Focal Length ExplainedCamera Lens Focal Length Explained
Sample Image Captured with a Wide Angle Lens

Wide-angle lenses are generally considered to be 35mm and below and afford a far greater field of view. These lenses are often thought of as having the best focal length for landscape photography, sought after by landscape photographers who can make use of getting more in the frame.

Standard lenses sit around the 50-60mm range and are suitable for a variety of objects at mid-range distances such as portraiture. They provide a focal length similar to what the human eye sees.

Telephoto lenses are longer lenses and offer a far greater capability to zoom in on a subject. 70-200mm range lenses are commonly used by portrait and event photographers, while they are also useful for sports and wildlife photography.

Super-telephoto lenses are, as their name suggests, super-long telephoto lenses and often veer into 300mm and above. These lenses have the invaluable ability of getting you a tight crop of subjects that are considerably distant, which makes them perfect for professional sports and wildlife photography.

Camera Lens Focal Length ExplainedCamera Lens Focal Length Explained
Sample Image Captured with a Telephoto Lens

A Small Sample of our Huge Lens Range

Choose the best camera lens for you

At Ted’s Cameras, we have a wide range of resources to help you get started and ensure you’re choosing the best camera gear for your needs. Read our beginner’s guide to shooting in manual mode, and browse our range of camera lenses to get inspired. To get expert advice on all purchases, you can also visit your local Ted’s Cameras store and speak to our expert staff.

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