Focal Length in Video Camera
If you’re new to video production, you might’ve come across the term ‘focal length’ quite often. In simple terms, focal length is the distance between the lens and the image sensor when a subject is in focus. It determines how much of the scene will be captured and how big or small the subject will appear in the final footage.
Understanding Focal Length
Focal length is measured in millimeters (mm) and it affects two important aspects of video recording- field of view and magnification.
- Field of view: This refers to how much of a scene is visible through the camera lens. A shorter focal length (wide-angle lens) captures a wider field of view while a longer focal length (telephoto lens) captures a narrower field of view.
- Magnification: This determines how big or small a subject appears in the final footage. A shorter focal length produces less magnification making subjects appear smaller while a longer focal length produces more magnification making subjects appear larger.
The human eye can see at an angle of around 120 degrees, but most video cameras have a narrower field of view. The choice between short or long focal lengths depends on what you want to achieve with your video recording.
Types of Focal Lengths
Focal lengths are categorized into three types based on their characteristics – wide-angle, normal, and telephoto lenses.
- Wide-angle lenses: These have shorter focal lengths (less than 35mm) than standard lenses and capture more area in each frame. They’re perfect for capturing landscapes, interiors, architecture and other wide scenes that require everything to be in focus.
- Normal lenses: These have a focal length between 35mm to 70mm and are the closest to what the human eye sees.
They’re great for capturing portraits, interviews, and general footage.
- Telephoto lenses: These have longer focal lengths (more than 70mm) and capture a narrower field of view. They’re useful for capturing distant subjects like wildlife, sports events or concerts.
The Relationship Between Focal Length and Depth of Field
Focal length also affects ‘depth of field’, which refers to the amount of area in front and behind the subject that appears sharp in focus. A shorter focal length (wide-angle lens) produces a deeper depth of field while a longer focal length (telephoto lens) produces a shallower depth of field.
A shallow depth of field is useful for creating cinematic effects where only the subject is in focus while the background is blurred. This effect is commonly used in music videos, films, and commercials to draw attention to specific elements within a scene.
Conclusion
In conclusion, understanding focal length is crucial for videographers as it determines how their footage will look like. Choosing the right focal length depends on what you want to achieve with your video production and the story you want to tell through your visuals.
Whether you’re using a wide-angle lens for capturing scenic landscapes or a telephoto lens for zooming into your subject from afar, remember that every decision counts when it comes to creating high-quality video content.
