What Is the Focal Length of a Lens?

The basics: what is focal length?

Focal length is an important concept in photography and videography that determines how your camera captures images. Simply put, it is the distance between the lens and your camera’s image sensor when the subject is in sharp focus. This distance is measured in millimeters and determines how large or small your subject appears in your image. A lens with a short focal length provides a wider field of view, ideal for landscapes and interior photos. A lens with a long focal length zooms further in on your subject, which is perfect for portraits and capturing distant details.

How does focal length influence your images?

Focal length has a major influence on the composition and perspective of your photo or video. Lenses with a short focal length, such as fisheye and wide-angle lenses, give you a wider field of view and allow you to capture more of the scene in your image. This is ideal for landscapes and architecture. Lenses with a long focal length, such as zoom and telephoto lenses, allow you to capture details of distant subjects and create a stronger depth effect, making your subject stand out more against a blurred background. This is especially useful for portrait photography and sports photography.

In addition, focal length also affects the distortion and perspective of your photo and video. Wide-angle lenses can cause distortions at the edges of your images, while telephoto lenses help create a more flattering perspective, which is often desirable in portraits.

Zoom lenses:

A zoom lens offers a variable focal length, which means you can zoom in and out to cover different distances without changing lenses. This gives you a lot of flexibility and convenience, especially when capturing dynamic scenes such as events or while traveling. For example, a 24–70mm zoom lens allows you to switch between wide-angle and telephoto, enabling you to easily adjust your composition.

Prime lenses:

A prime lens has a fixed focal length. Although you cannot zoom in or out, prime lenses often offer higher image quality and better low-light performance than zoom lenses. They usually have a larger maximum aperture, resulting in a depth-of-field effect that is ideal for portraits and artistic photography. The fixed focal length can encourage you to think creatively about your composition and your position in relation to your subject.

Full frame sensor:

With a full frame camera, the focal length of your lens directly corresponds to the specified specifications. A 50mm lens on a full frame camera therefore has a focal length of 50mm, which means you can expect the perspective and composition as designed by the manufacturer.

APS-C sensor:

Crop-sensor cameras have a smaller image sensor than full frame cameras, which affects the effective focal length. These cameras have a crop factor, often around 1.5x depending on the brand. This means that a 50mm lens on a crop-sensor camera has an effective focal length of about 75mm (50mm x 1.5). This crop factor magnifies the field of view, giving you a longer reach without changing the lens.

Tip 1: Choose the right lens

Choose the right lens to properly capture your subject. For architecture and landscape photography, use a wide-angle lens with a short focal length. For portraits and capturing details of distant subjects, telephoto lenses with a longer focal length are ideal.

Tip 2: Experiment with perspective

Change your focal length to play with perspective and composition. Use a long focal length to create a compression effect, where the background appears closer. Use a short focal length to get a wider perspective to show more of your surroundings.

Tip 3: Watch out for distortion

When using fisheye and wide-angle lenses, distortions may occur at the edges of your image. Try placing your subject in the center of your image to minimize this.

Tip 4: Stabilize your camera

With long focal lengths, camera movement can more easily cause blur. Ensure a stable posture or use a tripod to guarantee sharp images.

Short & Powerful: Focal Length

In our video “Why focal lengths are so important” you get a quick and clear explanation of what focal length actually means. This short summary is ideal if you want to quickly understand how focal length affects your photography and videography, without being overwhelmed by too many technical details. Watch the video for a visual explanation and examples that show how focal length can change your images.

Fisheye lenses:

Fisheye lenses offer an extreme wide angle and create a unique, spherical distortion of your images. They are perfect for capturing panoramic scenes or creative and abstract photos. Ideal for interior photography, architecture and artistic shots where you want to capture a wide field of view with a dramatic effect. The focal length is often between 8mm and 16mm.

Wide-angle lenses:

Wide-angle lenses are excellent for architecture, landscape photography and other situations where you want to capture a wide environment. They provide a larger field of view and make it possible to capture more of the scene in your image. They are also useful for capturing large groups of people and impressive views. The focal length is often between 14mm and 35mm.

Macro lenses:

Macro lenses are designed for extreme close-ups, allowing you to capture fine details of small subjects, such as flowers, insects or textures. They offer high magnification and sharp focus on small objects, perfect for nature photography and product photography where precision is important. The focal length is often between 60mm and 105mm.

Prime lenses:

Prime lenses offer a fixed focal length and are known for their excellent image quality and larger aperture openings. They are ideal for portraits, where a beautiful blurred background (bokeh) is desired, and for general photography where you want to take the time to carefully consider your composition. The fixed focal lengths range between 24mm and 135mm.

Zoom lenses:

Zoom lenses offer flexibility through a variable focal length. This makes them ideal for dynamic situations such as events, sports or travel, where you want to quickly adjust your composition without constantly switching lenses. They are also useful for all-round photography, from wide landscapes to detailed close-ups. The focal length ranges from, for example, 24–70mm to 70–200mm.

Telephoto lenses:

Telephoto lenses are perfect for capturing distant subjects. They are often used in wildlife and sports photography, where you want to approach subjects from a distance without disturbing them. Telephoto lenses create a compression effect that helps bring background details closer and changes the perspective of your photo. The focal length is often between 100mm and 600mm.

Which lens should I buy?

Now that you have a better understanding of focal length and how it can influence your images, you may be wondering how to apply this knowledge when choosing a lens. The right focal length plays a crucial role in determining the composition, perspective and range of your photos. Want to know which lens best suits your photography needs and how to choose the ideal focal length? Discover it in our article about choosing the perfect lens for your situation.