Understanding optical zoom and digital zoom is the difference between having that pixel perfect image and an image you know is flawed.
One of the many decisions you will need to make when choosing a new camera is if you want, need, or should even use digital zoom.
In this article we go over both optical zoom and digital zoom, along with considerations for each of them.
What Is Optical Zoom?
Often referred to as “true zoom,” optical zoom is performed completely within the lens. The optics within the lens physically move to magnify, or enlarge, a part of the view onto the sensor.
Standalone cameras, like DSLRs and mirrorless, refer to zoom capability in focal length.
Expressed in millimeters (mm), the higher the focal length, the more magnification the lens provides. For example, the 80 – 400 mm zoom lens has a minimum focal length of 80 mm and a maximum focal length of 400 mm. It can also focus at any length in between.
Point-and-shoot cameras express their optical zoom in x numbers, such as 2x, 4x, etc. This just means the camera’s lens can magnify the image 4x larger.
Phones are slightly different. As they need to stay very thin, they don’t have lenses that move. Instead they use magnified prime lens (fixed focal length). Even though the lens doesn’t move, phone manufacturers still call this “optical zoom,” and it is also expressed in x numbers, such as 2x, 4x, etc.
What Is Digital Zoom?
Often referred to as “fake zoom” digital zoom is not really zooming at all, but rather cropping.
Unlike optical zoom that’s done in the lens, digital zoom is done within the camera.
Essentially, the computer in the camera crops the central area of the image. It then must stretch it back out to fit the original image size. This stretching destroys pixels which the computer fills back in with less detailed pixels.
Though computers have gotten much better at doing this, it’s still very destructive to the image. These filled in pixels do not have the same level of detail of the original pixels.
Point-and-shoots, phone cameras, and some mirrorless cameras come with digital zoom capability. I’m not aware of any DSLRs with this functionality.
Digital zoom is expressed in x numbers, such as 4x, 10x, etc. Which again just means it makes the image 10 times larger.
Optical Zoom vs Digital Zoom, Which Is Better?
Optical zoom is far better than digital zoom, as it does not degrade image quality. However, sometimes optical zoom does not get you close enough to your subject.
Cropping an image in post-processing is a much better and less destructive way of filling the frame with your subject.
When you work in post-processing, you can edit the image as much as you want. If you don’t like your crop, just reset the image and start again. However, digital zooming is permanent, you can’t undo the crop made within the camera.
Are There Any Benefits To Digital Zoom?
Ease of use is the most notable benefit of digital zoom.
Instead of cropping in post-processing, the camera has already done the work for you. No additional software, or computer needed, everything is done in the camera when you push the shutter.
If you only plan to use the images on a small viewing surface, like a cell phone, this is likely to work out just fine. The degradation of digital zoom is most noticeable in larger formats.
An Impressive Optical Zoom In A Small Package
It’s most tempting to use digital zoom with a cell phone, as optical zoom is so restrictive.
Plus, I completely understand not everyone is keen to walk around with a DSLR and massive lenses to get those nice clear zoomed in shots. However, newer point-and-shoot cameras have really been pushing the limits in optical zoom. They make a nice compromise between size, cost, and capability.
With 83x optical zoom, Nikon’s COOLPIX P950 has the equivalent focal length of a 2000 mm lens! Even as a DSLR user, I’m impressed. With that type of optical zoom, there’s no excuse for stretching into digital enhancement.
If you do choose a product with digital zoom, I recommend learning how to identify when the digital zoom is enabled. Most newer cameras have a beep or some type of warning, so you can make a conscious decision based on how you want to use the photo.