We usually describe a lens by its focal length. What does it refer to and how does it affect your images? Find out in this article.

Lenses are classified as wide-angle, standard, or telephoto depending on their focal lengths. Ultra-wide-angle lenses are a subset of wide-angle lenses, whereas medium telephoto and super telephoto lenses are subsets of telephoto lenses.

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At 16mm, we can capture the entire façade of the fire station as well as the road and the hedge in the foreground. As the focal length increases, details appear bigger in the frame while more of the foreground and the building is cropped out. 200mm gives us a good close-up of the building name and the crests below it.

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Due to physics, a lens with a shorter focal length has a wider angle of view, and one with a longer focal length has a narrower angle of view. And that’s how we came to use focal length to describe the angle of view of a lens!

Learn more about how to make the most of wide-angle lenses in: Exploring Wide Angle Lenses Part 1: Photo Effects of Wide-Angle Lenses 24mm Closeups: 3 Simple Exercises for Mastering Wide-Angle Perspective

Also see: Why Is a Super Telephoto Lens Necessary for Sports Photography? What is the difference between a 200mm and 300mm telephoto lens?

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Ultra-wide-angle lenses exaggerate perspective so distances between objects look bigger. When combined with the wide field of view, it can bring out a sense of space.

Any focal length above 135mm full-frame equivalent is considered telephoto. However, 70 to 135mm (full-frame equivalent) is considered short or medium telephoto. These are popular for portrait and product photography due to their natural perspective and comfortable working distance for close-up shots.

2015413 — Reproduction ratio of a lens is the ratio of the real size of the object and the size of the object in the photograph.

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You need a very long focal length to capture a detailed close-up picture of the moon without cropping. The image above was captured at 1600mm using an 800mm lens and a 2x extender.

The focal length also affects many other aspects of your image, such as perspective and depth of field. To find out more,  see 4 Lens Concepts to Revolutionise Your Photos.

A longer focal length… - Captures less of the scene (= has a narrower angle of view) - Makes distant objects appear bigger (= has a higher magnification)

FOV tofocallength

This focal length is measured when the lens is focused to infinity (far into the distance). This is because when the lens is focused to infinity, light rays enter the lens almost parallel. When focused on a nearby subject, they enter the lens at an angle.

A shorter focal length… - Captures more of the scene (= has a wider angle of view) - Makes distant objects appear smaller (= has lower magnification)

Learn composition techniques that leverage on the characteristics of different lenses in: Professional Composition Techniques (3): Making Good Use of Lenses

Let’s look at what happens when we shoot at different focal lengths from the same position. Note: For ease of illustration, the angles shown in this article are the horizontal angle of view.

When picking a lens, one of the first things you must decide on is the focal length or focal range that you want. This is because the focal length describes the angle of view, i.e., it tells how much of the scene in front of you the lens can capture.

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Light entering the lens converges (crosses) on its way to the image sensor. This convergence point is known as the optical centre of the lens and has the sharpest focus. The focal length is the distance between this convergence point and the image sensor.

Learn the best ways to create amazing images and videos, share your works with the community and be inspired by our community.

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Focallength formula

Focallength

Ultra-wide-angle lenses take in so much that they are perfect for capturing grand scenes and large objects that are right in front of you, especially in tight spaces where you cannot move further back.

Notice how the buildings don’t appear to converge towards the top. They would on a wide-angle lens due to perspective exaggeration.

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Telephoto lenses provide an angle of view that is much narrower than human vision. 70-200mm lenses provide the classic telephoto focal range.

A standard or “normal” lens gives a perspective that is very close to that of human vision. Most kit lenses are standard zoom lenses. The popular RF50mm f/1.8 STM “nifty fifty” lens is a standard lens on a full-frame camera, whereas the RF28mm f/2.8 STM is a slightly wider standard lens on an APS-C camera.

To eliminate virtually all glare on your eyeglass lenses, ask for Neverglare Advantage, an anti-reflective coating for your lenses.

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Getting up close to birds and other wildlife requires a special type of telephoto lens: a super telephoto lens. You may want to combine it with an extender for even further reach.

Jan 29, 2024 — Sunlight, lamplight and other lights are usually unpolarized. But passing light waves through filters can 'polarize' them.

Learn more about what you can do with a standard lens in: Standard Lens Techniques: Using the Point of View to Draw the Viewer In 50mm Portraits, My Style: Creating A Picture of a Memory

Depending on the scene and your intentions, you might not need to go ultra-wide to frame what you want to show perfectly.

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When you look straight ahead with your bare eyes, the field of view in focus is around 50° to 60°. Wide-angle lenses are any lens that gives a field of view wider than that. Ultra-wide-angle lenses are a special kind of wide-angle lens.