What is focal length?
Many factors are put in place when creating videos to ensure excellent results; one of the most crucial factors is the camera lens focal length. With that said, the question arises; what then is the focal length?
The focal length simply is the distance between the front of the camera lens and the sensor. It measures the distance from where light rays converge on the lens and where the subject is produced on the camera’s sensor. The focal length of a camera lens is measured in Millimeters (mm).
Focal length plays a vital role in video footage by determining how clear the images captured will be. Longer focal lengths narrow the angle of view, and clear images are achieved.
On the other hand, the shorter the focal length, the broader the angle of view, the lower the quality of images formed.
Why is focal length essential in videography?
Focal length is used to achieve three significant things in video production;
- The focal length changes the visual settings of the image being captured.
- It controls how the backgrounds and environment will be seen from the viewer’s point of view.
- It tells the videographer the extent of the field of view in the frame.
Camera basics: Choosing the best focal length for video
Choosing the best focal length for video is subjective when it comes to filmmaking. Various focal lengths serve different purposes. Therefore, in trying to figure out the best focal length to work with on a video shoot, one must consider the context, nature of the work, and even shoot location.
The easiest way to make a focal length choice is to consider the effects different focal lengths have on the subject. And also how it helps viewers get the producer’s intent. Here are some key points to consider when choosing the best focal length for video;
- Depth of field
The depth of field of a video is simply how narrow or broad the area of focus is. (1) In achieving a specific depth of field, the focal length of the camera lens should be put into consideration when making a decision. Shorter focal lengths will produce a wider depth of field while longer focal lengths will result in a shallow depth of field.
Distortion has to do with the magnification of subjects in a field of view. Many video makers use long focal lengths to magnify the original size of the subjects. For instance, in hero movies, the hero is made to appear bigger compared to other shots captured in the scene.
However, distortion may have a negative effect on the subject. In close-up shots on the face, the nose may appear more prominent than other parts of the face. Hence, it disfigures the appearance of the subject.
- Angle of view
The angle of view is the primary determinant of how zoomed-in a lens will be. A shorter focal length has a larger angle of view, so more of the background can be captured. On the other hand, a longer focal length narrows the angle of view and captures less of the background. (2)
However, more of the subject image is accentuated. To a large extent, the focal length impacts the composition of the image formed. For larger images, use shorter focal lengths and for smaller images, choose longer focal lengths.
Categories of camera lenses focal length
There is a specific category of focal length that would give desired output based on the videographer’s style and personality. Overall, filmmakers should choose the focal length for video that works best for the subjects and the project’s nature.
Camera lenses with focal lengths wider than 24mm are categorized as ultra-wide lenses. These lenses have the most expansive field of view possible and can be used for landscape video shoots.
Not only that, ultra-wide lenses are great for shooting epic and momentous environments. However, there is a downside to using an ultra-wide-angle lens. The percentage of distortion in the image is higher. Therefore, choosing an ultra-wide lens for video is dependent on whether the filmmaker wants distortion or not.
Focal lengths of 35mm or less are categorized as wide-angle lens sizes. They allow the videographer to compress more background into the camera sensor’s frame. These lenses are not suitable for landscape videography, unlike ultra-wide lenses.
However, they can be used for full-body portraits where more of the scene is seen and the subject. Another plus to using a wide-angle lens is, it is also suitable for low-light shooting.
Standard angle lenses have focal lengths between 35mm to 55mm, and they have typical focal lengths as that of the human eye. If the videographer wishes to create videos with the same angle of view as a real-life scenario, standard angle lenses are the go-to.
Generally, standard lenses are considered to have focal lengths. Normal angle lenses are the best focal length for street videography and do not produce distortion, a common flaw of wider angle lenses.
Another property worthy of mention is, these lenses have small apertures. Therefore, they are great for video shoots with low lighting. The aperture allows more lights into the sensor. If you want to learn more about how camera lenses work in low light, check out our article on the best camera lens for low light.
Focal length of 50mm is perfect for street filming. The camera lens has a normal angle and it gives a natural finishing touch to the video. It portrays subjects as they are in a real-life setting.
Telephoto lens sizes
Any focal length wider than 70mm is categorized as a telephoto lens. They are long focus lenses and can be used to make far images appear closer. The upside of telephoto lenses is they produce little to no distortion and subjects.
These camera lenses are further subdivided into three categories as;
- Short telephoto lens
Telephoto lenses with shorter focal lengths between 85mm and 135mm are the best focal length for separating specific parts of the scene or the subject. They are also used to thin out the depth of field without necessarily bringing the subject too close or too far.
- Mid-range telephoto lens
Mid-range telephoto lenses are famous among wildlife and sports videographers. They have long focal lengths between 200mm to 400mm. They are suitable for shooting subjects from afar without moving closer to them.
- Super telephoto lens
Super telephoto lenses are the most powerful of camera lenses with focal lengths longer than 400mm. They are the best focal length for video where the filmmaker can’t get near the subject.
A fearful bird in the wild or a dangerous wild animal should be filmed from afar at a safe distance. A super-telephoto lens would save the day.
However, these lenses are weighty and may require external support like tripods or monopods to carry their weight during long shoots.
Also read: What is a Telephoto Lens?
35mm is the standard focal length for an interview. However, for a natural feel from the viewer’s discretion, a 50mm focal length can also be used to film the interview footage.
Wide-angle lenses have the best focal lengths that work in tight spaces like video shoots in a bedroom or a kitchen.
When it comes to choosing the best focal length for video, it is a decision that cannot be taken lightly. Careful consideration must be put in place before selecting a specific focal length for a particular project.
The focal length determines the end product of video footage to a large extent. Each focal length has its unique properties. While a 50mm focal length is perfect for shooting videos with a natural feel. On the other hand, camera lenses wider than 400mm focal lengths are ideal for shooting video from a safe distance.
Which of these focal lengths do you use for your video? Feel free to share your thoughts with us in the comment section below
- Annie Leibovitz. (2021, August 2). Learn About Depth of Field in Photography: The Ultimate Guide. Retrieved from https://www.masterclass.com/articles/learn-about-depth-of-field-in-photography#what-is-depth-of-field-in-photography
- StudioBinder. (2021, November 7). What is FOV — The Importance of Field of View in Photography. Retrieved from https://www.studiobinder.com/blog/what-is-fov-definition/