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What does mm mean?
Most photographers/videographers have a sound working knowledge of the camera lenses’ basics. However, little details such as ‘mm’ inscribed on the lens may be a bit of a head-scratcher. That said, the question arises, what does mm mean on a camera lens?
A typical camera lens has an “mm” number written on it. The mm is millimeters, and it’s the union representing the focal length. By simple definition, the focal length is the optical distance between the point where light rays converge to produce a sharp and crisp image and the camera’s sensor. (1)
Basically, the camera lens focal length describes the lens’ field of view and also its magnification. The larger the focal length, the wider the subject’s images formed will be. Focal lengths are usually indicated in numbers.
Focal length and its usefulness
Focal length is used to achieve three important things in photography/videography:
- It 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.
Types of lens focal length
Camera lenses’ focal lengths are of two types, which are;
- Zoom lenses
These types of lenses have a range of variable focal numbers. A camera such as 24mm-70mm is a zoom lens, and it provides the camera user to bring the subject closer or farther away with little or no distortion about it.
- Prime lenses
Unlike zoom lenses, prime lenses have a single f-number, and it is fixed. One can only function with a focal length that does not zoom; getting a close shot will require the videographer to move closer physically to the subject. (2)
Understanding the standalone features of different camera lenses mm will help videographers use them to add desired perspectives to the video created.
Categories of camera lenses focal length
To get the best out of camera lenses, one must have a concise understanding of the focal lengths and how they function differently. Different focal lengths have standalone characteristics, and each adds a unique perspective to photos and videos, respectively.
Here are the categories of lens focal length;
Ultra-wide angle
Camera lenses in this category have focal lengths between 8mm and 24mm. Ultra-wide lenses are ideal for capturing sweeping captivating moments. This lens category helps creatives produce amazing pictures/videos by including a significant amount of the scene into the frame.
Another unique quality of an ultra-wide lens is its expansive field of view. This field of view comes in handy in landscape videography and capturing the architectural details of the scene. In addition, the aperture of this lens encourages handheld shooting. Not only that, it can work perfectly in low-light conditions.
Wide-angle
This lens category has a broader field of view compared to a standard lens, and they have focal lengths between 24mm and 35mm. Using them for a shoot allows one to compress more of the subject’s scene into the camera’s sensor.
At this lens focal length, shooting the subject without excluding the background details is easier. Furthermore, 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 that it is also suitable for low-light shooting.
Standard angle
Standard angle lenses produce images close to that of the physical eye. These lenses have a focal length range of 35mm – 55mm. 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 angle lenses are the ideal focal length for street videography and do not produce distortion, a common downside of wide-angle lenses.
Another reason videographers popularly use these lens categories is the smaller aperture. The aperture allows the entry of light even in challenging conditions. Hence, they are great options for creating videos when it is dark.
Also read: 35mm vs 50mm: Which Prime Lens is Good for You?
Telephoto angle
Camera lenses with focal lengths between 70mm and 300mm or even more are called telephoto angle lenses. Due to the long focal lengths, these lenses can bring distant subjects closer without distortion.
For shoots where getting too close may scare the subject away, such as a fearful bird in the wild, a telephoto lens will get the job done seamlessly. However, these lenses are weighty and may require external support for their weight during extended shoots.
Telephoto angle lenses are further classified into three groups 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.
- Mid-range telephoto lens
Mid-range telephotos have long focal lengths between 200mm to 400mm. They are common among wildlife and sports videographers for shooting subjects from afar.
- Super telephoto lens
These are the most powerful camera lenses with focal lengths longer than 400mm. They are the best focal length for a video where the filmmaker can’t get near the subject.
Also read: Sigma 17-50mm f/2.8 Review
A higher mm doesn’t necessarily mean a better camera lens. However, the higher mm means a longer focal length with which videographers can easily capture shots at a distance without any distortion.
The 50mm camera lens is best for street videography. This lens’s focal length is versatile and closest to the human eye. It portrays the subject as seen in a real-life setting. However, for crop sensors, 35mm is a better option.
Conclusion
When asked the question, what does mm mean on a camera lens?; the simple answer that should quickly come to mind is focal length. Remember, the focal length is represented by millimeters (mm) a, affecting how zoomed in or out the image will be. Not only that, but it also determines how much of the background will be seen in the frame.
Which mm camera lens is your go-to for your video project? Feel free to leave us your thoughts in the comment section below.
References:
- Todd Vorenkamp. (2015, October 07). Understanding focal length. Retrieved from https://www.bhphotovideo.com/explora/photography/tips-and-solutions/understanding-focal-length
- Alyssa Maio. (2020, May 17). What is a Prime Lens, and What are the Benefits of Using One? Retrieved from https://www.studiobinder.com/blog/what-is-a-prime-lens-definition/