What Does The mm Mean On A Lens? An Extensive Guide

Included in this guide:

Every beginner photographer must have wondered what this “mm” means on the lenses. So what does the mm mean on a lens? Well, the mm after a value printed on lenses is called a focal length. Every camera lens comes with a different focal length. MM is defined as millimeters. So if your camera lens has a 24 – 105mm written, then that means it has a focal length of 24 – 105 millimeters. Some lenses even have a fixed focal length.

What is a Focal Length?

In simple words, the focal length is the zoom capability of a lens. If the focal length is 140mm then that means you will be able to zoom at a higher rate. If your focal length is 50mm then that means you won’t be able to zoom as much.

Focal length simply defines the zoom capability of a camera lens. People buy the highest focal length camera to capture the farthest entities. When you cannot reach a certain point, you simply use the zoom capability to capture the beautiful scene with more magnification.

Why do Some Photographers Choose a Higher Focal Length Camera Over a Lower One?

Higher Focal Length Camera Over a Lower One?

A longer focal length means you would get less field of view but more magnification. Higher focal length cameras allow you to shoot far-distance objects or wild animals. You can get a great view captured with a good focal length lens camera.

Whereas a lower focal length camera lens has a higher field of view but lower magnification options. It can be used to take portraits or vlogging.

What are Telephoto Lenses?

Higher Focal Length Camera Over a Lower One?

A Telephoto lens has an increased focal length, it can be used to shoot far away mountains or any other entity. You can even get the most detail out of it along with an accurate angle view. Telephoto lenses are available from 70mm in length and go upward. Each type of length has a certain purpose to it.

When you want to get closer to a far-away object, you use a telephoto lens. Lenses have a tendency to cause a certain distortion of some sort and that is why different types of focal lengths of lenses are available. For example, a wider angle lens could change some of the features of your subject in a shoot.

So if you are still wondering what does the mm mean on a lens then here it is. When you higher up the length, the faces of your subject could start to get wide and look flatten up. And at a lower millimeter length, they could look thinner. So the more perfect length is 70mm for many photographers out there. For portrait taking it is 85, it always depends upon the subject as well.


The higher focal value lenses are capable of high magnifications while the lower focal value cameras have low magnifications. Another thing is that the lower mm value gives you a wide-angle view, whereas the high mm value can give you a lower-angle view but a lot more detailed one. I hope you have now got an idea of what mm means.

Thanks for reading!