There are two types of lenses in photography and videography: variable focal length and fixed focal length. When you carry a variable focal length lens, you will be able to produce a variety of shots. If you are carrying fixed focal length lenses, you will need to change your lens to capture wide, medium and close-up shots.
Variable Focal Length
A variable focal length lens (VFL), more commonly called a zoom lens, can change focal lengths within a certain range, thereby changing the magnifying power of the lens by zooming in or out. From a stationary position, if the lens has a short focal length, the object being documented will be smaller and more of the background will be shown. From that same position, a lens with a longer focal length will make the subject larger, eliminate some of the background and exaggerate the depth of field. As an example, a 100mm lens will make the subject twice as large and show less of the background than the image produced by a 50mm lens. This effect is known as lens compression. The ability to zoom in and out with VFL lenses makes these lenses more versatile for uncontrolled action and allows you to pack less for the field.
Fixed Focal Length
If you choose fixed focal length lenses (FFL), you will need a number of lenses with fixed focal lengths if you will be recording images with varying depths of field. A fixed focal length lens - often referred to as a prime lens - has only one focal length, which cannot be changed. Fixed focal length lenses usually provide more clarity because of less glass and come with a faster aperture. For example, the fastest aperture when shooting at 85mm on a 24-105mm lens is usually f/4-f/5.6. Fixed lenses often provide faster apertures such as f/1.2-f/1.8, which creates eye-catching critical focus on your subject, which is great for studio interviews. Unlike VFL lenses, weight does not shift as much in FFL. This makes FFL the better option to use with gimbals.
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. They have a short focal length, so 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, 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, also referred to as medium lenses, can be 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 and they recreate the scene from a natural perspective. Check whether your normal lens is variable or fixed to make sure you know if you need to bring one lens or many lenses to the 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 can be 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 subjects that you have to be far away from for safety or practical reasons, such as during explosions, fires, heavy-equipment use or when you just can't get there 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 your camera remain perfectly still. Use a tripod or monopod if one's available.
TELEPHOTO