• 04 Jan 2022 21:56
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What is optical zoom and digital zoom? What's different?
  • What is Optical Zoom?
  • What is Digital Zoom?
  • Compare optical zoom and digital zoom
  • Conclusion

What is Optical Zoom?

Before learning about what optical zoom is, let's have a quick look at the concept of zoom. Zoom is the ability to enlarge or reduce the size of an image or subject in front of the lens. Zooming in gives you a closer look at objects while zooming outlets you capture a larger space.

Optical zoom is composed of many different layers of lenses, when we adjust the zoom in or out, there will be a mechanical change of the lens and the camera's focus, helping the camera to see farther than usual but the image is still clear. strokes.


Optical zoom changes the image based on the camera's hardware, giving a magnified image but the definition is still very real. The lenses with optical zoom capabilities are most commonly found today on dedicated cameras (DSLRs) or current high-end smartphones.

Optical zoom across devices will provide the same results, but depending on the quality of the camera's glass may affect that result.

What is Digital Zoom?

Digital zoom (also known as digital zoom), like optical zoom, digital zoom still zooms in on objects, but without the need for excessive mechanical or lens elements.

It will essentially crop the areas around the scene to make it look like you're getting closer to the subject. The rest of the image is enlarged by an algorithm, hence the name digital.


Digital zoom is currently developing quite strongly, thanks to its convenience, low cost, and thriving technology used not only on cameras but also on smartphones with impressive zoom capabilities.

The quality of digital zoom is also being significantly improved compared to before in the integration of AI intelligence, when zooming in or out, AI will automatically adjust the image for clarity.

Compare optical zoom and digital zoom

Image quality

The image quality between optical zoom and digital zoom has a clear difference, optical zoom has better image quality, the image is not broken and blurred.

The reason is that for optical zoom, the focal point is adjusted by moving the optical lens back and forth and the displayed image is enlarged accordingly. Therefore, there is almost no loss in image quality.

The image quality on digital zoom is not too high, meaning some data will be lost during zooming. The algorithms will add pixels to keep details in the image when zoomed in, but not so perfectly.

Zoom ability

Because digital zoom works by processing algorithms, the zoom size of cameras with numerical zoom is much higher than optical zoom. However, in return, the image quality is reduced compared to the original.

In addition, optical zoom can adjust the lenses to change the optical focus so that the camera can zoom further than usual.

Zoom time

Due to the mechanical structure, the time to optical zoom until the image can be displayed will be a little longer than that of an arithmetic zoom with an algorithmic mechanism.


Optical zoom is much more expensive than digital zoom due to its small structure and special manufacturing technology.


Digital zoom was a selling point in the early days of digital cameras, but over time, camera manufacturers focused less and less on this spec, instead of focusing on optical zoom. is growing more and more.


Each type of zoom will have different advantages and disadvantages, specifically:

Digital zoom is cheap, popular, large zoom size, and easy to upgrade and update through software. However, the image quality drops noticeably at maximum zoom.

Meanwhile, the optical zoom is smaller in size than the arithmetic zoom, and the image quality remains the same after zooming. Its minus point is that it is difficult to upgrade and update due to its physical structure and high cost.

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Emma William By, Emma William
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