In photography and videography, two types of lenses exist: variable focal length and fixed focal length.
Variable Focal Length
A variable focal length lens, more commonly called a zoom lens, allows you to change focal lengths within a certain range, thereby changing the magnifying power of the lens by zooming in or out. When using a zoom lens from a stationary position, a shorter focal length will make the subject appear smaller and capture more of the surrounding background. From the same position, increasing the focal length will make the subject appear larger and reduce the amount of visible background. For example, a 100mm lens will make a subject appear twice as large and show less of the background compared to a 50mm lens. Furthermore, longer focal lengths decrease the depth of field, making the background appear more blurred. This foreshortening effect on the apparent distances within a scene, particularly noticeable with longer focal lengths, is known as lens compression. The ability to zoom in and out makes zoom lenses more versatile for capturing unpredictable action and reduces the amount of equipment needed in the field.
Fixed Focal Length
A fixed focal length lens – often referred to as a prime lens – has only one focal length, which cannot be changed. Prime lenses are often chosen for their superior image clarity and faster apertures. They allow for a wide range of depths of field by adjusting the aperture setting. For example, while a 24-105mm zoom lens may have a maximum aperture of f/4, prime lenses often offer much faster apertures, such as f/1.2 to f/1.8. These faster apertures are ideal for studio interviews and creating a shallow depth of field, drawing focus to your subject. Prime lenses also tend to be more compact and lightweight compared to zoom lenses. Because of this, and the lack of a shifting weight distribution, fixed focal length lenses can be easier to balance on gimbals than zoom lenses.
Both types of lenses give you the opportunity to master a technique known as a rack focus. Rack focus is the recorded shift of focus from one object to another.
Let's zoom in on some scenarios to better understand which focal length will give the best shot.
Take Your Shot
Use labels along the top to progress through scenarios. Click the learn more button for more in-depth information.
Take Your Shot
- Wide
- In a tightly enclosed area
- Of a large object
- Close to the subject
- Of a moving subject
Wide-angle
Wide-angle lenses can be fixed or variable and range between 15-35mm. Because they have a short focal length, they show a large portion of a scene. They're perfect for documenting scenes in cramped spaces, such as on an aircraft carrier, or when there is a lot of movement, like on a helicopter. Remember, though, that these lenses distort the image and perspective, particularly as the field of view increases.
Lens facts
- 15-35mm lens
- Allows a large amount of light to reach the focal plane
- Great depth of field
Tips For a good shot
Capture some foreground interest to bring viewers into your shot.
Wide-angle
Take Your Shot
- Of natural perception
- For historical documentation
- Of a ceremony or portrait
Normal
Normal lenses, or medium lenses, are either fixed or variable, and range between 24-105mm. To best replicate the human eye, use a 50mm with a full-frame sensor or a 35mm with a crop sensor. These lenses are ideal for ceremonies, historical documentation and military portraits because they don't distort the image but rather recreate the scene from a natural perspective. Check whether your normal lens is variable or fixed to determine if you need to bring one or many lenses for a shoot.
Lens facts
- 24-105mm lens
- Allows as much light as possible to reach the focal plane
- Average depth of field
Tips for a good shot
Don't be afraid to use this lens for most shots. From ceremonies to portraits to documentation, a normal lens is the Swiss Army knife of lenses.
Normal
Take Your Shot
- Narrow
- Far away
- Unapproachable
- Small
Telephoto
Telephoto lenses are either fixed or variable, and range between 70-200mm. They have a long focal length, so they let little light reach the focal plane, producing images that magnify a narrow portion of the scene. This makes them ideal for shooting faraway subjects for safety or practical reasons, such as explosions, fires, heavy-equipment use, or when you can't get to a scene fast enough. Remember, these lenses misrepresent the proximity of your subject to background and foreground objects, making things appear closer than they are, so use them with caution.
Lens facts
- 70-200mm lens
- Allows very little light to reach the focal plane
- Shallow depth of field
Tips for a good shot
When using a telephoto lens, it's critical that your camera remain perfectly still. Use a tripod or monopod if one is available.
Telephoto