When first looking into purchasing a lens, the MM in the lens name can be a confusing concept. So many numbers! You may wonder what the MM means on a lens and if it will greatly impact your photograph. Simply put – yes, it will, as this number controls the perspective at which you see (and shoot). 

What Does MM Mean On A Camera Lens?

When looking at the name of a lens, you’ll see a number(s) preceded by MM (for example, 35mm or 70-200mm). This refers to the lens’s focal length or perspective at which you see. Basically, this number tells you how zoomed in the lens is, to be straightforward about it.

The functional distance between the front of the lens and its focal plane is how camera engineers tend to describe focal length. In everyday terms, the focal length number impacts how much you see and the angle of view when you look through the lens. For example, a focal length for a 16mm lens will show a much wider frame than that of a 200mm lens.

Now, when you look at a lens name, some lenses have only one number in front of the MM, and others have two numbers with a dash in front of the MM. This indicates whether this lens can actually zoom in and out, changing its focal length. 

A 50mm lens forever stays at 50mm. A 24-70mm lens can zoom in and out, changing its focal length from 24mm to 70mm when turning the lens barrel. Lenses that don’t zoom are called Prime lenses, and the others are Zoom lenses. 

Is A Higher MM Lens Better?

A common misconception is that the longer the focal length, the better the lens. This is an understandable thought process, considering longer lenses are much more expensive! However, the larger the MM does not mean the lens is better – lenses don’t really work that way. 

In a very general statement, the lens is the primary artistic tool in the photography equation. However, the camera is important too (absolutely). The final result of your image depends on your lens, not the camera. 

How your photograph looks is a direct result of the MM of the lens. Smaller numbers equal a wider field of view, while higher numbers are narrower, more zoomed-in perspectives (like a telescope or binoculars). 

Therefore, high or low MM numbers have nothing to do with whether or not the lens is better and simply to do with the field of view of your photo! Higher MM lenses are generally more expensive than lower MM lenses due to their size, as that involves more engineering and materials. 

This leads me to the next section.

What Each MM Of Lens Is Best For

Lenses are divided into six categories based on their focal lengths. Each of these MMs of the lens are best for certain types of subjects. 

To precursor this, however, you can photograph any subject with each of these lenses, but they may not always be the best suited for them (it’s really about personal taste and creative choice here). 

Ultra Wide Angle: 14mm

Ultra wide-angle lenses are the widest field of view you can get in an optic! Landscape, architecture, and real estate photographers love ultra-wide-angle lenses because of that sweeping field of view. 

You can capture an entire captivating landscape in just one shot. Or make a small room look rather large.

The glass has to curve to create the ultra-wide-angle perspective, which can highlight nearby objects while giving distant objects the appearance of being even further away. 

The result looks a bit like a fishbowl effect. Because of the curved lens distortion, living subjects such as people and animals don’t always look great when photographed by an ultra-wide angle. 

Wide Angle: 14mm – 35mm

A little bit more reasonable on the optic distortion, regular wide-angle lenses are still just as fantastic for landscapes (if not even more desirable for them). The field of view is still vast despite being narrower than an ultra-wide angle. 

When photographing landscapes, architecture, or real estate without such an intense wide-angle effect, these are the lenses of choice. 

Standard: 35mm – 85mm

Standard lenses are the bread and butter for photographers. The benefit of standard lenses is the lack of optic distortion, so your subjects won’t have their proportions altered as a result. The glass tends to be quite flat. 

These lenses mimic the perspective the human eye sees the most, so they also tend to be very easy to use for brand-new photographers.

As such, standard lenses are most commonly used for portraits, pets, still life, street photography, and more. Actually, street photographers, in particular, love standard lenses because they best represent everyday life due to the lack of distortion. 

Another benefit of standard lenses is their focusing distance. You can be close to your subject and still get them in focus. 

Short Telephoto: 85mm – 135mm

Short telephoto lenses are rather loved for portraiture, even though they have a place for wildlife and action photography. People, pets, models, and fashion photographers often use a short telephoto lens. 

The reason for this is that the focal length of the short telephoto causes distortion as well, but this is flattering for living subjects. The longer focal length creates what is called subject compression, which ever so slightly squeezes and tightens a subject’s proportions, making a person or animal even more flattering to look at.

Granted, this distortion isn’t something you’d see immediately, but you can see it compared to a standard focal-length lens photo.

Because of the longer distance, short telephoto lenses can be used for action photography and wildlife. However, other telephotos tend to be a more popular choice for these subjects. 

The one little snag about telephoto lenses is that you need to be a bit away from your subject, as these lenses don’t focus up close. But this being said, short telephoto lenses still allow you to photograph in a smaller studio space and be able to focus. 

Medium Telephoto: 135mm – 300mm

The medium telephoto is best for nature photography and sports photography. With these longer focal lengths, the photographer has to be even further away from the subject, making medium telephoto lenses less great for portraits or studio work and excellent for sport and wildlife. No one wants to be too close to a bear anyway! 

Because of the requirement to be further away from your subject to focus on this lens, these lenses don’t do too well in the studio or indoor settings unless you have a lot of room to back up. 

Super Telephoto: 300mm+

The super-telephoto lens is there to do wonders for sport and wildlife extreme photographers. 

Photographing carnivorous animals is much safer with a super telephoto lens, allowing you to be very far away and still photograph the creatures as if they were right up close to you! 

Sports photographers like those who capture the Kentucky Derby or baseball feel the same. Photographers can’t be too close to the action for the safety of the camera wielders and the sports players themselves, so super telephoto lenses make it appear that they’re up close. 

However, these lenses genuinely need a large distance between the photographer and the subject and are very heavy. Most super telephoto lenses require a monopod or tripod as they are too heavy for handheld shooting while avoiding camera shake. 

Especially when you are just getting into photography, figuring out which lens to get is super overwhelming. The easiest way to choose the right focal length (mm) is to make sure it’s as versatile as possible. I would recommend getting a standard focal length lens in the 35mm-85mm zoom range. I personally love using a 24-70mm since it’s a perfect daily lens for my camera and photo needs. Then as you get more interested in a certain style of photography, you can get a more specific lens to suit your other styles.

Happy Shooting!