You’re probably familiar with the term “zoom.” In simple terms, “zooming” is simply the process of using your camera to get visually closer to your subject. But did you know that there are two different types of zoom—optical and digital—and that one is actually a lot better than the other? Can you guess which one it is?
If you guessed “optical,” you’re right, and here’s why. Although some digital cameras have both optical and digital zoom capabilities, optical is always going to give you better results. That’s because optical zoom uses the lens of the camera—in other words, the optics—to zoom in on your subject. I'll explain the difference between optical and digital in a moment, but first let's take a closer look (pun intended) at optical zoom.
Lenses are complicated pieces of equipment that are made in part out of shaped glass components called “elements.” It’s the element’s job to capture light, bring it into focus and then send it on to your camera’s image sensor.
In an optical zoom lens, these elements move back and forth when the lens zooms, changing the distance between the camera’s image sensor and the center point of the lens. That’s how an object is magnified (or de-magnified). It happens because of the mechanics of the lens, so the quality of the image doesn’t change when you zoom in or zoom out.
Digital zoom, on the other hand, is fake zooming. When you digitally zoom, there are no mechanics involved at all, and the lens has nothing to do with how large or small the image becomes in your viewfinder. Instead, what’s really happening is that your camera is cropping the image on the fly, just as you would crop it yourself in post-processing. So at maximum digital zoom instead of getting a full-resolution image, you get a reduced-quality version of whatever your camera is “zooming” into. The only thing that’s really happening is that your camera is excluding all of the information outside of the object you’ve zoomed in on, so you get an image that’s basically exactly the same size and quality as what you would get if you took the zoomed out version and just cropped it yourself in Photoshop Elements or Lightroom. In fact at maximum digital zoom what you’ve done is just blown up a very small part of the image, which makes all the individual pixels bigger, which makes for a poorer photo.
Since digital zoom is exactly the same process as cropping in post-processing, it makes sense to stay zoomed out and just crop instead. When you crop a photo in post processing, you get to view it on a big screen—and that gives you the ability to be a lot more precise about what you decide to include or exclude than you would be when you’re limited to a small LCD screen. Plus you can always refer back to the original if you change your mind—a choice you don’t have when you digitally zoom.
So why does this all matter? When you digitally zoom, you sacrifice clarity, and the reason why clarity matters is because you can’t print images that have poor clarity—at least not with good results. A digitally zoomed image may make for a decent 4x6 print as long as it was shot at the highest resolution setting on a camera with a decent number of megapixels—but as the print size increases you’ll start to see undesirable effects like fuzzy details, then fuzzy subjects, and even blocky areas in very low resolution photos. If you never print your photos this is less of a problem, but many of us not only like to order sets of 4x6 photos, we like to see a few images in larger formats, too.
Keep in mind that the best zoom lens you’ll ever have is your own two feet—so if you’re using a camera that has no optical zoom at all, you should first try simply walking towards your subject. That’s the best alternative to shooting a low-resolution image with digital zoom, or to cropping—and sometimes it’s even better than optical zoom.
How can I tell if my camera zooms digitally or optically?
Sometimes the easiest way to tell if you camera has digital or optical zoom is to just look at the camera body. A compact or “point and shoot” camera, which is a basic, pocket-sized model, is likely to have “optical zoom” printed right next to the lens.
If it doesn’t say “optical zoom,” it probably isn’t—that’s because “optical zoom” is a selling point and manufacturers aren’t likely to leave it off if it’s a feature of the camera. Another clue is if the lens retracts—a lens that pops in and out of the camera when you switch it on is likely to have optical zoom. But just because the lens doesn’t pop out doesn’t mean it isn’t optical zoom—there are also fixed-position zoom lenses. When in doubt check your camera’s manual—or simply Google your camera’s model and look for marketing materials. Manufacturers are nearly always clear on which type of zoom their camera has—just beware of marketing that touts “digital zoom” as a plus. It isn’t (as you know), but that’s never stopped an ad designer from saying so.
Some cameras just don’t have digital zoom, so don’t be alarmed if you can’t find any reference to it in your manual. It’s much more likely to be a feature of point-and-shoot or compact digital cameras. If there’s no reference to it in your manual, it’s not a feature of your camera.
Finally, if your camera has interchangeable lenses (it’s a DSLR or a smaller camera like a micro 4/3rds), it’s unlikely to have digital zoom. Digital zoom isn’t necessary or desirable when you can just switch over to a longer focal length lens, and it’s not an advantageous selling point for a manufacturer who’d really rather be selling lenses.
Disabling Digital Zoom
Many cameras actually combine optical and digital zoom—if you’re trying to get very close to your subject, you may reach the end of your camera’s optical zoom capabilities and then digital zoom will take over. If you’re not aware of this then you may end up being disappointed by the quality of that shot, so make sure you check your camera’s manual to see if it has this feature. In many cameras this is customizable, which means that you can set the point at which digital zoom takes over, and you may even be able to turn off digital zoom altogether (which is the option I personally recommend).
DSLR cameras: Again, if you have a DSLR camera, you won’t be able to find the digital zoom option because the higher quality DSLRs don’t need digital zoom trickery. That means your camera always uses optical zoom.
Camera Phones: Your camera phone almost always uses digital zoom, because there is no moving lens inside the phone to create an optical zoom. In these cases, I always recommend moving closer with your feet rather than zooming in using the camera. The only exception to this policy would be if you can’t physically get any closer—in which case cropping in post-processing is still going to be better than digital zoom.
Keep in mind …
When you’re camera shopping, it’s a good idea to pay close attention to what type of zoom your prospective new camera has, and whether or not it has combined digital and optical zoom. Chances are, the manufacturer is going to be touting that combination as plus: “combined zoom of 12x!). But remember that a camera that has 6x optical zoom combined with 6x digital zoom is not, in fact, the equivalent of a camera with 12x optical zoom—despite what the marketing materials may be trying to tell you. Remember that you’ll start to get poor quality whenever that digital zoom kicks in, so for all intensive purposes a 6x optical + 6x digital zoom is really just a 6x optical zoom.
I hope if you’ve been plagued by unexplainably fuzzy photos from your compact camera or smartphone, that this tip made you go “ah ha!” This is perhaps one of the easiest fixes in all of photography—just don’t use digital zoom. You’ll get instantly better, fuzz-free shots just by turning that option off and zooming optically, or the old-fashioned way—with your feet.