The focal length of a lens is an important aspect of filmmaking because it determines the field of view in your frame, along with how elements may be compressed or separated inside the shot. Read on for Film School Tips and to learn how the focal length of a lens can affect your framing and shot selection!
Whether you’re using a zoom or prime lens, the standard measurement for focal length of a lens is in millimeters. Simply put, the technical definition of focal length for the filmmaking industry is the distance, in millimeters, from the camera’s image sensor to the center of the lens. This also explains why a lens with a focal length of 20mm is physically shorter than a lens with a focal length of 250mm.
HOW THE FOCAL LENGTH OF A LENS AFFECTS YOUR FRAMING AND SHOT SELECTION
When looking through the viewfinder of your camera, a 35mm lens will generally resemble the natural vision and framing of the human eye (not taking into account sensor size, which is a different topic for another time). So, any lens less than 35mm will begin to widen your camera’s field of view, allowing more objects in the immediate area to be seen in frame. The lower the focal length, the more your view becomes wider and distorted, resembling a “fish eye” look.
Increasing the focal length of a lens will do the exact opposite. A lens with a higher focal length will begin to crop your shot and “zoom” closer toward your subject. By changing lenses from a 35mm to a 150mm, you are effectively increasing the focal length between the lens and the camera’s sensor, which is creating a zoom effect, narrowing your field of view and bringing your frame closer to the subject. Look at the illustration below to visualize the changes that focal length can make to your shot!
HOW DO THE DIFFERENT FOCAL LENGTHS COMPRESS OR SEPARATE ELEMENTS IN YOUR SHOT?
By changing the focal length of your lens, you’ll be able to manipulate the elements in your shot to achieve different cinematic looks depending on your filmmaking goal. When using a lens with a small focal length (35mm or less), your shot will be wider. This will add separation and distance to the elements in the background. In essence, they will seem smaller and farther away. At the same time, the elements closer to your lens will appear larger and more dominant in frame.
When using a lens with a large focal length (50mm or more), it will compress the elements in your shot, making the distance between each element appear closer to one another. This may not seem favorable, but generally, larger focal length lenses will create a shallower depth of field. This makes those elements in the background that are appearing closer seem out of focus. The depth of field achieved by a large focal length lens is what many filmmakers refer to as “creating a cinematic look”.
With a variety of lenses to choose from, filmmakers have many ways to tell their stories. The good filmmakers, however, will manipulate their lenses to influence the image in order to better tell their story. The more you know, the better filmmaker you’ll be! Use our tips whether you’re in film school or a professional in filmmaking to get the most out of your shots!
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If you have a true passion for the Film and Video industry, F.I.R.S.T. Institute‘s Film School in Orlando, Florida is a great place to get the hands-on training needed to launch your filmmaking career. As a student you will work on several industry related projects such as commercials, testimonials, documentaries, music videos, and even a short film.
At F.I.R.S.T. Institute’s Film School, we pride ourselves on offering small classes with career specific training and our industry professional instructors are dedicated to offering you film career advice that will get you your dream career. You could be our next success story! Classes are enrolling now, so contact us today!