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.
The basic explanation: Focal length tells us the angle of view
The basic explanation: Focal length describes the 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.
A shorter focal length…
- Captures more of the scene (= has a wider angle of view)
- Makes distant objects appear smaller (= has lower magnification)
A longer focal length…
- Captures less of the scene (= has a narrower angle of view)
- Makes distant objects appear bigger (= has a higher magnification)
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.
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.
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.
Lens categories according to focal length
Lens categories according to focal length
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.
| Lens category | Focal length (35mm equivalent) |
| Ultra-wide angle | 24mm and below |
| Wide angle | 35mm and below |
| Standard | 40mm to <70mm |
| Medium telephoto | 70 to 135mm |
| Telephoto | >135mm |
| Super telephoto | 400mm and above |
Ultra-wide-angle
RF14-35mm f/4L IS USM @ 14mm, f/8, 0.5 sec, ISO 100
Ultra-wide-angle lenses
Prime lenses: ≤24mm (full-frame), <15mm (APS-C)
Zoom lenses: 11-24mm, 14-35mm, 15-30mm, etc.
Common uses: Landscapes, interiors
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.
Shot at 16mm
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.
Wide-angle
RF28mm f/2.8 STM @ 28mm, f/5.6, 1/320 sec, ISO 100
Wide-angle lenses
Prime lenses: 28mm, 35mm (full-frame)/ 16mm, 22mm (APS-C)
Zoom lenses: Covered by ultra-wide-angle zoom lenses and standard zoom lenses
Common uses (other than ultra-wide-angles): Landscapes, documentary, street, snapshots
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.
Shot at 35mm
Depending on the scene and your intentions, you might not need to go ultra-wide to frame what you want to show perfectly.
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
Standard
RF50mm f/1.2L IS USM @ f/1.2, 1/500 sec, ISO 200
Standard lenses
Prime lenses: >35mm to around 60mm (full-frame)/ Around 28 to 35mm (APS-C)
Zoom lenses: Any lens that covers the 50-60mm range (full-frame) or 32mm to 40mm range (APS-C)
Common uses: Travel, landscapes, street, portraits, everyday life! This is one of the most versatile types of lenses.
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.
RF24-50mm f/4.5-6.3 IS STM @ 50mm, f/8, 1/400 sec, ISO 100
Notice how the buildings don’t appear to converge towards the top. They would on a wide-angle lens due to perspective exaggeration.
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
Telephoto
RF70-200mm f/2.8L IS USM @ 200mm, f/8, 1/320 sec, ISO 100
Telephoto lenses
Prime lenses: Above 135mm (full-frame); above 85mm (APS-C)
Zoom lenses: 70-200mm, 100-300mm (full-frame); 55-210mm (APS-C)
Common uses: Nature, portraiture, action, concerts
Special types of telephoto lenses
Medium telephoto: 70mm to 135mm (full-frame)/45 to 85mm (APS-C)
Super telephoto: See next point
Telephoto lenses provide an angle of view that is much narrower than human vision. 70-200mm lenses provide the classic telephoto focal range.
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.
Also see:
5 Things to Try with a Telephoto Lens
How Do I Effectively Use Foreground Bokeh on a Telephoto Lens?
Super telephoto
RF600mm f/4L IS USM on EOS R7 @ 600mm (840mm equivalent), f/4.5, 1/4000 sec, ISO 640
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.
RF800mm f/5.6L IS USM + Extender RF2x @ 1600mm, f/16, 1/1000 sec, ISO 400
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.
Also see:
Why Is a Super Telephoto Lens Necessary for Sports Photography?
What is the difference between a 200mm and 300mm telephoto lens?
Learn composition techniques that leverage on the characteristics of different lenses in:
Professional Composition Techniques (3): Making Good Use of Lenses
Technical explanation: What focal length really refers to
The (simplified) technical explanation: What focal length really refers to
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.
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.
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!
