If you’re in the market for a digital camera, you’ve very likely come across the words optical zoom and digital zoom a few times. But, what is optical zoom? It’s important to understand what it is and how it compares to digital zoom in photography.

This guide will take an up-close look at optical zoom. We’ll explain how it differs from digital zoom so you’ll be best informed to make a decision when you buy your next camera or lens.

lens with optical zoom 75-300mm
Photo by Joshua Hoehne on Unsplash

Understanding zoom

When it comes to photography, to “zoom in” basically means to increase the size of your subject in the frame, without actually moving yourself or your camera any closer to the scene. On the contrary, zooming out means the opposite — to make your subject appear smaller in the frame. Zooming can be achieved in two ways: in the lens with optical zoom or in-camera with digital zoom. Let’s explore each method.

Methods of zoom

As we mentioned above, there are two basic ways to zoom in photography:

  • Digital zoom. This is done digitally in-camera, as the name implies. The way it works is the camera will crop into the center of your image and then digitally enlarge it. 
  • Optical zoom. This type of zoom refers to the camera lens elements moving back and forth to increase or decrease the focal length of the lens. 

Which lenses can zoom?

You just learned that optical zoom refers to the type of zoom created when you move the glass elements inside a lens to change its focal length. This is the type of lens referred to as a “zoom lens” because it has a range of focal lengths you can choose from. If someone has a prime lens, they cannot zoom with it, as it has a fixed focal length. 

It’s easy to remember — zoom lenses can zoom, prime lenses cannot. Lenses are named for their focal lengths. So, if a lens has only one focal length listed in the name, it’s a prime. If there are two focal lengths listed, it’s a zoom.

Some optical zoom lenses can be large, heavy and expensive
Photo by Harrison Haines from Pexels

Optical zoom vs. digital zoom: Which is better?

As you can see, digital zoom and optical zoom are two very different technologies. Which one is better for you and your shooting situation is largely subjective, however. Let’s go over some pros and cons of each.

Digital zoom, as we mentioned previously, is performed in-camera by cropping and enlarging your image. Depending on how far you zoom, this can result in a large loss of resolution and image quality. However, technology is getting very good these days, so this is less and less of a problem. Still, most professional photographers consider this to be “fake” zoom and prefer to shoot in RAW and crop later to make enlargements, if necessary.

Optical zoom is done by truly moving the elements of the lens, so as long as your lens is sharp you will never have any loss of image quality or resolution by zooming. But, depending on how far you want to zoom, you may need a very expensive and heavy zoom lens to get the same amount of reach you’d get with a much lighter and less expensive digital zoom camera.

So, depending on your camera and your situation, you may prefer optical zoom, digital zoom, or a combination of both!

Photo by Reafon Gates from Pexels

Final thoughts

Using zoom is the way photographers get up close to their subject, without actually getting physically close. Now that you understand what optical zoom is and how it differs from digital zoom, you’re ready to make a more informed camera or lens purchase.