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What does optical and digital zoom mean in smartphone photography?

Zoom power is increasingly getting a lot of attention when talking about smartphone camera specifications. With brands like Samsung, Sony, and Huawei disrupting the market with devices with insane zoom capabilities, optical and digital zoom are some of the words being thrown.


But what do they mean exactly? What is the core technology that powers all of them? How does it affect the quality of the images your smartphone camera can produce? And which of them should you look for in a smartphone?


What is the zoom in smartphone cameras?

In smartphone photography, zoom is simply a way to zoom in on an interesting object in front of the camera or make it appear closer. Of course, in a more general definition, zoom also covers a method for de-zooming the appearance of an object to make it appear further away than it actually is. That’s why you’ll often hear terms like “minimization.”

However, most people don’t care how much a smartphone camera can be minimized; They are mostly concerned with how much you can zoom in. So, we’ll focus on the “zoom” side of things. But how exactly does zooming happen?

Whether it is a DSLR camera or your smartphone camera, zoom is achieved by changing or adjusting the focal length of the camera. Focal length is the length between the image sensor in your smartphone camera and where the light converges and focuses the image.

The higher the focal length, the greater the magnification. On the contrary, a shorter focal length gives you a larger angle of view but less magnification. If you would like to learn more about focal length, we have previously provided a detailed introduction to focal length in photography.

In traditional photography, one way you can zoom in is to swap the lens for one of your preferred focal length. Alternatively, you can use a zoom lens. The zoom lens allows you to mechanically adjust or increase the focal length to achieve zooming, or simply zoom in.

Unfortunately, zoom lenses tend to be bulky. To house the mechanical arrangements of components and parts needed to build a true zoom lens, your phone will be thick, heavy, and have an unsightly camera bump. In an age where consumers crave thin, sleek phones, huge camera bumps aren’t a start.

However, zoom must be performed on smartphones. but how?

Optical zoom in smartphone photography

Optical zoom is the appropriate form of zoom in which the moving parts of the viewfinder are mechanically modified to increase the focal length to achieve zoom. Optical zoom is “zoom in as it was meant to be.” Unfortunately, zoom lenses that can adjust the focal length are not yet a thing on smartphones, so optical zoom in smartphones is achieved by switching between cameras of different focal lengths.

Unlike DSLR cameras, optical zoom in smartphone cameras is not achieved by the actual movement of mechanical parts to adjust the focal length. Instead, when you want to use 2X zoom, your smartphone will switch to another camera that matches the focal length required to achieve that zoom power. If you are wondering why many modern smartphones come with more than one camera, this is one of the reasons.

So every camera has a fixed focal length, some shorter and some longer. Your smartphone simply switches to the lens with the longer focal length to give you zoom in/out. This is why some experts refer to the optical zoom version on smartphones as a multi-camera zoom. However, optical zoom is “the true form of zoom” and delivers similar results as if you were closer to the subject.

Although the lens or camera switching technology used in smartphones works, there is a small problem. Since cameras do not use a zoom lens that gradually adjusts the focal length, continuous zoom is not possible on almost all smartphones.

This means that if your smartphone is equipped with multiple fixed focal length cameras that can achieve 2x, 4x and 5x optical zoom, when zoomed in, the true optical zoom level simply jumps from 2x to 4x and then to 5x as with cameras. Transformation. Everything in the middle, like 3x or 4.5x zoom, for example, is achieved through digital zoom.

But what is digital zoom anyway?

Digital Zoom in Smartphone Photography

Digital Zoom is a software-assisted attempt to replicate the results of optical zoom. In digital zoom, there is virtually no change in focal length. The camera only takes the image in front of it, cuts a section, and expands the cropped section to fill the available viewport. The digital zoom is less than the actual zoom and more than great cropping technology.

Because digital zoom involves cropping, the resulting image usually has a noticeable loss of quality. Let’s say you have a smartphone with a 20MP camera and you want to perform 2x digital zoom. What happens is that your smartphone’s camera will capture the 20MP photo, pin the 10MP part of the photo that contains the object you want to zoom in, and then cut out the other 10MP.

The 10MP portion containing the object of interest is stretched to cover the frame, often resulting in pixelation and an overall loss of quality.

So, if your phone offers 2x and 5x zoom, everything in between is likely to be handled digitally or using a hybrid approach called hybrid zoom. Hybrid zoom combines optical and digital zoom data using computational photography to create magnified images that exceed the lens’ true optical capabilities.

What type of magnification should you look for?

Often, smartphone manufacturers advertise their products with labels such as 20x zoom or 60x zoom. Sometimes a catchy name is added. Samsung has a 100x area magnification. Unfortunately, most of these stickers are just marketing ploys.

Before you get excited about the power of the zoom, you need to ask yourself: “How many of them are real optical zoom?” Sure, smartphones like Samsung’s Galaxy S series have impressive digital zoom power. This is possible thanks to the large sensors and a lot of megapixels, which gives it more accuracy to work with.

However, the digital zoom is still in a cropped state. Optical zoom is what provides true zoom and is the best form of zoom you should look for in a smartphone. Some smartphones with impressive optical zoom include Sony Xperia 1 IV, Samsung Galaxy S22 Ultra, Vivo X80 Pro, Pixel 6 Pro, and iPhone 14 Pro Max.

Zoom power is not as simple as it seems

Although some smartphone manufacturers talk a lot about how much their smartphones can zoom in/out, the zoom capabilities are not as straightforward as they seem. More magnification is not necessarily better; Depends on the type of zoom and the underlying technology that powers it.

Never buy a smartphone over another because it has a bigger zoom power label. 5x magnification can be better than 10x magnification. The actual zoom power is not related to the number of times the camera is zoomed in/out. It’s about how well the camera can adjust the focal length and the power of the underlying software that can help it improve image magnification beyond its optical capabilities.

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