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This post was most recently updated on September 25th, 2022

If you are a busy photographer, you may not have noticed all the different numbers printed on your lens. Or, you might have noticed, but aren’t sure what they mean? Perhaps you have found yourself wondering about these numbers and what they could mean?

They most commonly indicate what the camera lens is best used for, and how to set it up with your camera. Now, this information is super important and something we should be aware of. But how do we know what they mean?

Well, stick with us, as we have the answers for you! Today we explore the numbers on a camera lens and find out what “mm” means on a standard 50mm lens.

What Does The MM On A Camera Lens Mean?

When you take a close look at a camera lens, you’ll find that it has a digit with “mm” printed on it.

This figure stands for the focal length measured in millimeters. This focal length varies depending on the length, from 18mm up to 55mm and beyond.

How To Find Out What Focal Length Your Lens Has

The easiest way to find out the focal length of your camera lens is to check the number printed on the lens.

Depending on the manufacturer, this could be anywhere on the outside of the lens.

Alternatively, if you want to know exactly what focal length your lens has, you can measure it yourself.

All you need is a ruler and a piece of paper. Take a picture of the ruler against a wall and draw a line across it.

Then place the ruler on top of the picture and mark where the lines cross. Now divide the measurement by two and multiply it by 100. This gives you the focal length in millimeters.

How To Find Out What Focal Length Your Camera Has

To find out what focal length your camera has, simply turn the focusing ring on the lens until the image is sharp.

You should see a number next to the word “focal”. If this number is not there, then your camera does not have an internal autofocus system.

You will need to use manual focus instead.

If your camera doesn’t have an optical viewfinder, you can still determine the focal length using the LCD screen (for digital cameras only).

Simply hold the camera so that the display is facing upwards and look through the viewfinder window.

Focus on something far away and adjust the zoom until the object appears as a clear circle in the middle of the display.

Once focused, move closer to the object and check how much of the display is covered by the circle.

This tells you how long your lens is. For example, if the circle covers half the display, then your lens is set to 50mm.

What Is A 50mm Camera Lens Used For?

What Does 50mm Mean On A Camera Lens?

50mm lenses are great standard lenses that get a lot of different jobs done. They are good for taking portraits as well as landscapes and other general photography.

However, they don’t work well when shooting moving objects or capturing fast action shots.

They tend to be more expensive than other types of lenses, and they are a little more weighty so can be harder to carry around.

There’s no doubt that 50mm lenses are versatile but they aren’t suitable for all situations.

For instance, if you’re planning to shoot sports events, you’ll probably want to get a wider angle lens.

A wide-angle lens lets you capture a bigger area of the scene. It also helps to eliminate perspective distortion which makes objects appear larger or smaller than they are.

Types Of Camera Lenses

As a hobby photographer, you may be happy with your standard camera lens but there are plenty more lenses on the market.

You can find a lens for almost every purpose. Here are some of the most common types of lenses.

Standard Lenses (35 – 70 mm)

Standard lenses can cover a medium range of views. These are commonly used for portraits and close-ups but can also be used for some narrow landscape shots.

Wide-Angle Lenses (18 – 35 mm)

A wide-angle lens has a wide field of view. They’re usually used for landscapes and architecture.

Telephoto Lenses (70 – 200 mm)

Telephoto lenses create a narrow and shallow depth field of view. They can be used for sports or wildlife photography.

Macro Lenses (0.7 – 1.5 m)

Macro lenses are ideal for micro and macro photography. They allow you to get very close to your subject. They’re often used for closeups.

Zoom Lenses (2X – 10X)

Zoom lenses allow you to extend the focal length by changing the distance between the front and back elements.

Zoom lenses are popular because they let you take photos from far away and still have a large zoom range. The downside is that they can be heavy and bulky.

What Do All The Numbers On A Camera Lens Mean?

You may have noticed a lot of different numbers on your camera lens. These numbers on a lens tell you what it’s designed to do.

You can usually also find them in the settings of your camera. Here are some of the most common numbers on a camera lens.

Focal Length

The focal length refers to the size of the image formed by the lens at its widest setting. For example, a 100mm lens will form an image that is 100 millimeters across.

Maximum Aperture

This refers to the maximum diameter of light allowed into the lens, e.g. an f/1.4 aperture means that the lens allows only one-quarter of the available light in.

Minimum Aperture

On the other end of the aperture spectrum, the minimum aperture refers to the minimum amount of light that the lens can accept. For example, an f/16 aperture means that the lens accepts 16 times less light than the maximum aperture.

Angle Of View

This refers to how much of the scene is captured by the lens. If you were using a 24mm lens you’d see about 2% of the entire scene.

If you wanted to capture more of the scene you could use a longer lens. For example, a 28mm would give you 4% of the whole scene.

If you wanted to capture even more of the scene you’d need a 40mm lens which would give you 6%.

Final Thoughts

Camera lenses come in many shapes and sizes. You’ll notice that each type of lens has different characteristics.

It’s important to know what kind of lens you want before buying. There are lots of great options out there depending on your camera, so don’t feel limited by the ones mentioned here.