If I were to ask you to select a wide lens, would you know what that meant? If I told you to grab a long lens, would you stare at me blankly? When someone asks what millimeter lens you're using, do you grab a ruler?
Well, read the next article in our series to help you Choose the Best Lens for Your Project to learn the basics of a camera's focal length and how to decide what focal length to use to make your composition pop!
Understanding focal lengths will revolutionize your ability to communicate your vision and get the shot you want
While this is critical knowledge for cinematographers and other members of the camera team, it isn't necessary for directors and other crew to memorize the range of focal lengths - but having this understanding will revolutionize your ability to communicate with your camera team and get the look and effect you want.
Today, we're going to demystify a crucial concept that can make or break your shot composition: focal length. Whether you're a budding filmmaker or a seasoned director, understanding focal length is essential for choosing the right lens and capturing the perfect shot.
So, let's dive into the world of lenses and composition!
What is Focal Length, Anyway?
The technical answer is, focal length is the distance between your camera lens' optical center and the image sensor, measured in millimeters (mm). It affects the angle of view, or how much of the scene is captured and how the subjects within that scene appear.
Focal Length is the measurement (in millimeters) from the optical center (point through which a ray of light may travel without being affected) of a lens to the imaging plane (i.e. sensor) when a lens is focused at infinity
Shorter focal lengths (like 18mm) capture a wider field of view, making them great for landscapes or tight indoor shots. On the other hand, longer focal lengths (like 85mm) have a narrower field of view, ideal for close-ups and portraits because they make the subject stand out against a blurred background and show less distortion of a person's face.
A lens's focal length tells us the angle of view (how much of the scene will be captured) and the magnification (how large individual elements will be).
Focal length tells us the angle of view and the magnification of the image
Focal Length IS | Focal Length Is NOT |
Focal length refers to the distance from the optical center to the sensor, measured in millimeters | Focal length does not refer to the physical length of the lens - focal lengths can be physically longer or shorter than their optical focal length |
It tells you the angle of view and magnification of an image | It is not measured from any specific element within the lens - the optical center may be inside, in front of, or even behind the lens! |
Why Focal Length Matters in Filmmaking
Field of View: Focal length dictates how much of the scene you can see through your lens. Want to capture the grandeur of a sweeping landscape or the intimacy of a character’s expression? The right focal length will get you there. Different focal lengths, combined with an understanding of field (or angle) of view are associated with different shot types, though many directors and cinematographers feel free to buck the trend and use different focal lengths for certain shots to assist with creative expression (e.g. use an extreme wide-angle lens, like a fisheye lens, for disorienting closeups).
Depth of Field: This is the part of the image that's in focus. A shorter focal length (i.e., a "wider" lens) usually offers a greater depth of field, keeping more of the scene in sharp focus. A "longer" focal length can give you that dreamy, blurry background effect, perfect for isolating your subject.
Perspective and Distortion: Different focal lengths affect how subjects are perceived in relation to each other. Wide-angle lenses (short focal lengths) can distort features, making them appear exaggerated, which can be used creatively for dramatic effect. Telephoto lenses (long focal lengths) compress distances, making objects appear closer together.
How to Choose the Right Focal Length
Choosing the right focal length depends on what story you want to tell and how you want to tell it. Here’s a handy guide to get you started:
Understand Your Scene: What are you shooting? For wide, open spaces or big groups, go for shorter focal lengths (10-35mm). For individual portraits or close-ups, longer focal lengths (50-200mm) are your best bet.
Consider the Mood: Wide-angle lenses (short focal lengths) are fantastic for creating a sense of space and movement, while telephoto lenses (long focal lengths) are great for intimate, emotional shots. Think about the mood you want to convey.
Test and Experiment: Don’t be afraid to try different lenses. Many filmmakers carry a range of lenses to switch up the focal length depending on the scene. Play around and see what works best for your vision.
Film students often are taught using prime lenses before they touch a zoom, to help ensure they can make deliberate choices about their shot style
Mind the Distortion: For scenes where accurate portrayal of the subject is crucial, avoid very short focal lengths, as they can distort features. Conversely, for scenes where a little creative distortion adds to the storytelling, wide-angle lenses can be a fun tool.
Wide Lenses | Long Lenses |
Focal Length: Short (typically 35mm and below) | Focal Length: Long (typically 70mm and above) |
Field of View: Wide, captures more of the scene | Field of View: Narrow, focuses on a smaller portion of the scene |
Perspective: Exaggerates distances, making objects appear further apart | Perspective: Compresses distances, making objects appear closer together |
Use Case: Landscapes, architecture, interior shots, and group photos | Use Case: Wildlife, sports, portraits and close-ups, and distant subjects |
Distortion: More prone to barrel distortion, especially at the edges | Distortion: Less prone to distortion, but may have pincushion distortion at extreme lengths |
These differences affect how each type of lens is used and the visual effects they produce in photographs.
Key Takeaway
Get comfortable discussing focal lengths in terms of what millimeter lens you want to use for each individual shot. While not required for directors, it's highly recommended you have at least a working knowledge of focal lengths so you can communicate easily with your camera team.
Final Thoughts
Mastering focal length is like having a superpower—it gives you control over how your audience experiences your film. So next time you're setting up a shot, think about how different focal lengths can enhance your storytelling. Whether you're capturing the vastness of a desert, the coziness of a small room, or the intensity of a character's gaze, the right lens can make all the difference.
Happy shooting!
Further Reading:
What I think about when I think about Focal Lengths, Mark Wieczorek https://medium.com/ice-cream-geometry/focal-lengths-1a281a3509ed
Be sure to check out the rest of the series Choose the Best Lens for Your Project - more articles are being added all the time!
Check out the rest of the Choose the Best Lens for Your Project series
Focal Length: Next Steps to Greater Understanding
Selecting the Right Lens for Your Sensor Format
Image Circles: What Does That Mean, and Why Should I Care?
How to Buy and Sell Used Cameras and Lenses: A Beginner's Guide
And more are coming!
Got any cool stories or questions about focal length? Drop them in the comments below—we'd love to hear from you!
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