If you are in the market for a camera, especially a compact or fixed lens point and shoot camera, you’ve probably come across the terms optical and digital zoom. But what do these phrases mean? Is one type of zoom better than another? Camera manufacturers use all kinds of jargon to entice you to buy their products, but the important fundamentals are actually quite straightforward. Hopefully, after reading this article, you will be better informed on all things zoom.
What Is Zoom?
In photographic terms, to “zoom in” means to make your subject larger in the frame, without actually moving forward yourself (instead, zooming on your lens). On the other hand, to “zoom out” means to go the other way, or to make your subject smaller in the frame. Zoom lenses allow you to do this and are incredibly convenient. They allow you to change focal lengths without actually using a different lens entirely.
On a DSLR or mirrorless camera, zooming is done by either rotating a ring on your lens, or by pushing and pulling on the barrel of the lens. In the case of most compact cameras, zooming is done by turning a dial on the top of the camera. These motions adjust the focal length of the lens, allowing you to magnify the scene.
However, not all zoom is equal!
With optical zoom, the glass elements inside the lens move to increase or decrease the focal length of the lens. Any time you hear someone mention a “zoom lens,” they are referring to a lens with the ability to change focal length by moving its glass elements.
Optical zoom is the ideal way to zoom in while retaining as much image quality as possible. However, some cameras also advertise something called “digital zoom.” Do not confuse optical and digital zoom. They are not the same thing, as you will see in a moment.
One example of a lens with an optical zoom is the Fujifilm XF 100-400mm f/4.5-5.6 R LM OIS WR lens. This lens zooms from 100mm (a moderate telephoto) to 400mm (a strong telephoto). Notice how the barrel of the Fujifilm lens extends when the lens is zoomed in. Some zoom lenses do this internally, so you do not see the barrel lengthen, such as Nikon’s and Canon’s 70-200mm f/2.8 lenses.
Digital zoom is created in-camera, not using the lens’s optics. To do this, the camera crops into the centre of the image. Then the cropped capture is digitally enlarged back up to size by adding pixels to the picture. During this process, image quality can suffer drastically!
My iPhone 8 Plus has two lenses. One has a 28 mm focal length (in 35 mm equivalent terms), and the other is 56 mm. It also has a 10X digital zoom. Here are three images. They are taken at 28mm, 56mm (2X optical zoom), and 280mm (10X digital zoom) respectively. Notice how the image quality is severely compromised using the long digital zoom.
There is rarely a good reason to go beyond your lens’s optics and start using a camera’s digital zoom. Instead of letting the camera crop your photo for you, just crop it yourself on your computer. Even if you crop away half the picture, you will still have enough resolution to print 4×6 photos and more than enough size to post your images digitally on social media.
In those few cases when you need to get even tighter or want to make large prints, software programs will do a much better job of upsizing your image than the digital zoom on the camera. On1 Resize, Alien Skin’s Blow Up, and freeware by Gimp and Irfan View all do a good job at upsizing photographs.
The takeaway here is to ignore the digital zoom claims from camera manufacturers. If reach and image quality are essential to you, concentrate on optical zoom only.
There are two ways you will see the power of a zoom lens quoted. One method is by the lens’s focal length, and the other is by its zoom ratio. While focal length is used almost exclusively in the DSLR and mirrorless world, the zoom ratio is much more common when looking at point and shoot cameras. However, focal length and zoom ratio apply to both types of camera lenses.
Focal length describes the angle of view of the lens. The longer the focal length, the narrower the angle of view, and the more magnification you will experience. For example, Nikon’s 200-500mm f/5.6E ED VR Lens is an excellent lens for wildlife photographers. It allows you to get very close to your subject when zoomed to 500mm.
With compact cameras, the zoom ratio is used to indicate the power of the lens, rather than the focal length. You will see it listed in the advertising with an X, such as 3X or 10X. The zoom ratio is the value of the longest focal length of the lens divided by its shortest focal length. So, the zoom ratio for Nikon’s 200-500mm lens above is 500mm÷200mm, or 2.5X.
The X Factor
Let’s look more closely at zoom ratio (X factor), as it can be a bit confusing. For example, consider Nikon’s 28-300mm f/3.5-5.6G ED VR Lens. Although its reach isn’t nearly as far as the 200-500mm lens, its zoom ratio is much bigger. The 28-300mm lens has a zoom ratio of 300mm÷28mm, or 10.7X! So, the zoom ratio does not indicate how close you can get to your subject. A higher number simply indicates that there is a bigger range between the wide and telephoto end of the lens.
Cameras with the same zoom ratio do not necessarily have the same focal lengths! Let’s look at two more examples. Canon’s PowerShot SX740 and Nikon’s Coolpix B500 both have 40X optical zooms. However, when you dig a little deeper into their specifications, you find that the focal length (in equivalent full-frame terms) of the PowerShot is 24-960mm, while the Coolpix is 22.5-900 mm. In other words, if reach is of the utmost importance to you, Canon’s PowerShot will be more attractive to you. On the other hand, if you are a landscape photographer, and want to work with wider angles, the Coolpix will be more suited to your shooting style.
Using a zoom lens is a great way to get in close to the action when physically getting close is impossible. However, remember that optical and digital zoom are not created equal. If you have a point and shoot camera and want to zoom in tight, use the optical zoom. Although zooming in closer is tempting, the results using digital zoom will be disappointing, and you are better off just cropping instead.
If you are buying a new compact camera, do not use digital zoom to compare models. Instead, focus on the optical zoom specifications and – most importantly – the focal lengths of the lenses. Once you have your new toy, to prevent it from accidentally zooming past its optical limits, make sure you turn off the digital zoom feature in the menu.
Hi I’m Don in Las Vegas. I’m considering buying a Nikon Coolpix B500, but there’s some thing that I still don’t understand about the 40X optical zoom advertised for this camera. That’s pretty impressive capability so I wanted to research it and make sure I understood correctly. In your article you mention that camera’s ratio can zoom to 22.5mm to 900 mm. Well I’m not big on metric so I used an online converter to learn that 900mm is 35.4 inches. In the pictures of the camera I can see that the lens sticks out pretty far when zoomed way in, but it sure ain’t any yard-long camera so I’m still mystified. Can you explain and help us better understand what gives?
Focal length: 4.0 to 160 mm (angle of view equivalent to that of 22.5 to 900 mm lens in 35 mm  format)
Excellent article and well explained.Thanks
Artificial intelligence pixel enlargement zooming is not a bad thing ! – and it CAN be done in camera – like the Sony 1.1-2X Clear Image Zoom. You DO need to maximize your camera/len’s native IQ for best results ! This is much cheaper/easier than buying bigger lenses or tele-extenders ! – and some fixed lens cameras do not even have this option. AI pixel enlargement is a very acceptable option if kept to 2X or less with maximized IQ from high pixel density sensors and higher quality lenses.
Creating more pixels from fewer has been done for a couple of decades. It could always be accomplished in Photoshop and in the early years there were first plans, then actions, then plug-ins for optimized results. Adobe continued to work on this aspect of the software, to the point that the third-party plug-ins were rarely an improvement over what could be accomplished with the software, if one were wise in what they did.
How well AI enlargement works always depends on the quality of the pixels you start with, with image sharpness and noise being the most critical variables – and how much one intends to expand the pixels.
Inkjet printers have been using this technology for more than a decade as well, as many users don’t understand the concept of pixel density for a given use – that is I have an image with this many pixels, but want to use it for a web image and a 20×30 print – so when users want to make a big print from a file that lacks the pixels needed to do so WELL, it produces the best it can from what is supplied.
At the end of the day, there are many ways to make an image where the subject is larger than what was possible to capture. Depending on ones final needs, it can work just fine – or it can be challenging to impossible. No doubt, though, that creating more from less has improved significantly over the last couple of decades – just as sensors capable of capturing more high quality pixels have been developed and reasonably priced, too.
I was saddened by this article – in my opinion, it was as confusing as it was informative. Far too much crossing of ideas when, as your comments have made clear you lack cameras to try to KNOW for sure what you are talking about. I’ve taught many photography courses over the years and have and currently own many types of cameras, from cell phone to compact to advanced consumer to truly bridge cameras, as well as three different (soon to be four) different interchangeable lens systems (all Nikon). And, my specialty is wildlife, where zoom is critical to understand. Your example of the 200-500 on the D7100 was inaccurate simply because the D7100 is a cropped sensor (DX), working with a lens that will work with DX or full-frame (FX) camera. D7100 with the 200-500mm lens, the “zoom” or effective field of view (FOV) is 300-750mm. And that is optical, which is important for an end user to understand. I use several prime long lenses, typically with an FX body and often with teleconverters, which were not covered at all, yet they are critical to most wildlife shooters, and it’s important that people understand the pros and cons of working with teleconverters. With respect, either cover the subject well, or if you lack the gear/experience to do so, respect the community enough to pass on the topic rather than post an article that has big holes in it and is confusing for some of the areas it does cover.
A nice basic overview of zooming types. Is that bird a Siskin?
There are a couple of points that could be confusing however:
‘Then the cropped capture is digitally enlarged back up to size by adding pixels to the picture.’ – Normally no pixels are added to a picture when a digital zoom is used. Only the camera simply uses a reduced central area of the sensor to zoom, so you end up with less pixels being used and smaller files. What you might be referring to is that the digital viewfinder on compact and mirrorless cameras will retain a full screen view of the zoomed in image, but this doesn’t require adding any pixels since the EVFs are far lower res than any sensor.
‘..make sure you turn off the digital zoom..’. It is certainly the case that using large (5+ times) digital zooms will generally produce a poor picture, not only because the remaining number of sensor pixels will be low, but also because on compact cameras and smartphones the sensor is so small that the image is diffraction limited even wide-open, so when you zoom in (effectively enlarge) the picture you can see the diffraction blur more obviously. However, on cameras with high number of megapixels (say 20mp+), a reasonably big sensor (say 1-inch +) a modest (1.5-3 times) digital zoom shouldn’t degrade the image greatly when viewed up to A4 size. Additionally, there are obviously some situations when using the digital zoom is the only way to actually see and follow your subject accurately, especially BiF, so I wouldn’t agree with completely disabling the digital zoom function.
Having said that, you are of course correct that optical zoom is normally always the best option for high quality results.
This will be an informative article for some readers, but I think mooshing together discussion of smartphone and compacts with DSLRs is a bit confusing: while of course digital cropping (in camera or in software) will “degrade” the optics, it is an area where “size matters” a lot. Quite apart from lens optics, the difference in sensor size and pixel density lets a DSLR or larger format camera crop to image quality that is perfectly acceptable, even for print publication, despite it being less than the maximum resolution.
Thank you for your comments, Albin.
Unfortunately I don’t own a compact camera, so the only way I can demonstrate the degradation that happens when you use digital zoom, is to do it with my iPhone. And, I am not comparing the images from different cameras, but rather a comparison of optical and digital zoom in a given camera (iPhone or otherwise). Obviously, image quality depends on many other factors, such as the sensor and pixel size/density. However, that was not the aim of the article. The point of this article is to clarify the difference between the two types of zoom, and warn readers about the pitfalls of digital zoom.
Thanks again for contributing to the conversation.
I think it is pretty complete.
THANK YOU!! This was very helpful and I think I finally understand the zoom ratio! I have been very confused when buying cameras and lenses for birding as to why others were getting better close ups with supposedly smaller zooms on their lenses.
You are welcome, Cheryl. I’m glad it helped clear things up.
I really do think you should repeat his article with using the Huawei P30Pro.
It offers the equivalent to 16mm, 27mm, 81mm, 135mm, 270mm – and all in between!
Soo much better than an iPhone …
The brand makes no difference, the digital zoom offers less quality than the optical one, even with the best interpolation algorithm. Elizabeth didn’t evaluate a particular smartphone or point at shoot camera, her comparison was digital vs optical zooms, and it is valid
Hi Malcom, as Nestor said, this was not meant to be a comparison of different cameras. I needed an example of digital zoom, and as I don’t own a point and shoot, my only option was my cell phone.
I think someone needs to go camera shopping!