With the development of technology, the camera of mobile phones has greatly improved in terms of pixel and zoom capabilities, such as Xiaomi's 100 million pixels, OPPO Reno's 10x hybrid optical change, and Huawei P30 Pro's 50x digital zoom.

At present, the highest hybrid zoom of mobile phones is 10 times. Hybrid zoom is to use a lens after digital zoom to try to compensate for the previously lost pixels. Digital zoom is available at 20, 30, 50, 100, etc. above 10x hybrid zoom.

To put it simply, the mainstream mobile phones do not have "real optical zoom" at this stage, and photos taken with the mobile phone zoom will lose the picture quality. As the zoom factor increases, the imaging effect of the photo becomes worse.

So the question is, what is the significance of the high digital zoom of a smartphone? Why do other manufacturers use digital zoom as a selling point for new phones? What practical value can it bring to consumers?

Zooming with algorithms

The concept of zoom is still very vague to everyone. We try to make it clear to everyone in a simple and direct way.

In the era of film machines, there was only optical fixed focus and optical zoom. The former focal length was fixed, such as 50mm. It cannot be changed. To change the composition and picture, you can only "realize" by approaching or walking away.

The latter is to "zoom in" or "zoom out" of the subject by moving the lens within the lens.

Entering the era of digital cameras, zoom is split into optical zoom and digital zoom.

Digital zoom is also well understood, that is, the picture is cropped by the processor of the mobile phone, and the purpose of "zooming in" is achieved at the expense of image quality. This is why optical zoom is also called non-destructive zoom.

In the age of mobile phones, the concept of optical zoom has been subdivided into "physical optical zoom" like Samsung Galaxy S4 Zoom (the principle is the same as digital cameras), and "algorithmic zoom" such as iPhone 8 Plus or Huawei P20 Pro (also May be called "hybrid optical zoom").

At present, mobile phones with physical optical zoom on the market are basically extinct, because even the 5x lossless zoom technology of OPPO is not really "lossless", it is actually achieved by 3x optical zoom + digital zoom.

Phones like the Samsung Galaxy S4 Zoom are not mainstream. So now what we call optical zoom phones are basically algorithmic zooms.

That is, it has multiple lenses including wide-angle and telephoto, and through the cooperation between each other, it uses algorithms to simulate and realize the zoom in and zoom out of the screen.

From the perspective of the imaging quality of mobile phone zoom, optical zoom> hybrid zoom> digital zoom.

What's the point of a mobile phone's high digital zoom?

Since the current mainstream optical zoom mobile phones cannot completely guarantee that the photos taken are not damaged, what value does the high-power digital zoom of the mobile phone have?

In fact, the usefulness of digital zoom on mobile phones is mainly determined by the needs of people who use it.

Today, the digital zoom of mobile phones has been upgraded to 100 times. The 100x zoom is the maximum zoom factor of the Samsung Galaxy S20 UItra, but not through optical zoom, but through digital zoom.

If it's just for fun, it can be used to satisfy curiosity, but if you want to take photos with 100x digital zoom, the quality of the film must be very average, after all, 100x digital zoom gimmicks are greater than practical.

Digital zoom is not a new technology concept. Card machines and home DV (digital video cameras) more than a decade ago were equipped with digital zoom as standard, and it was hundreds of times motionless.

Nowadays, home DV basically does not mention digital zoom, and SLR cameras even refuse to have a relationship with digital zoom. Simply speaking, the selling point of digital zoom has been ruthlessly abandoned.

The reason is that the digital zoom does not change the size of the image on the photoreceptor by moving the lens (this is what optical zoom does), but it is achieved by cropping the image and then zooming in. The larger the magnification (digital zoom), the higher the quality.

On the bright side, the digital zoom on your phone can expand people's field of vision. It's like you could only shoot interesting things within 10 meters centered on you. Now it's expanded to 1000 meters. Then you can shoot interesting things. The probability will be greatly increased, and your circle of friends will be even more compelling.

In addition, the digital zoom of the mobile phone can compose the picture in real time, and adjust the angle of your position to match what you see. Without digital zoom, you can only compose the second composition after shooting, and the effect of the second composition cannot be seen directly when shooting, which is much less intuitive.

At present, the zoom capability of cameras in mobile phones is gradually improving. The first is the improvement of camera module hardware, and the other is the improvement of software algorithms.

The iPhone's camera is not high pixels, but it can take very good quality photos, a large part of which comes from the optimization of software algorithms.

Digital zoom can also achieve better image quality through software algorithms.

Due to the optimization of the camera algorithm, the image obtained by the 10x digital zoom will still be clearer than the manual magnification of the image by 10x.

Although the high-power digital zoom of mobile phones may be more gimmick than practical, in the future, with the advancement of AI technology and the update and iteration of camera hardware, the digital zoom of mobile phones may have a major breakthrough, even if it is 100 times digital zoom , The photos taken can also be close to lossless. For example, OPPO Reno's 10x hybrid zoom,

The 10x hybrid optical zoom is achieved in the form of a baton through three different focal length lenses. Compared with the ordinary 10x digital zoom, the former has better resolution.

To sum up

Taken together, the high-power digital zoom on mobile phones can lower the barriers to entry for ordinary consumers to shoot, and enrich the gameplay.

The extreme telephoto of 100x zoom is only part of the zoom. The ultra-long focal length can be "visible is what you get" within the framing range, and even records details that cannot be captured by the naked eye.

The addition of AI technology has made a new breakthrough in high-power digital zoom of mobile phones, which may be the development direction of mobile phone imaging systems in the future.

For the user, the high-power digital zoom of the mobile phone can select a suitable focal length for shooting in a limited space, and the photographer can "close" to the subject without moving at all. The mobile phone's maximum zoom capability of 100x allows complete recording of the subject.

The complete external appearance, approximate outline, detailed description and even text annotation of the object can be precisely adjusted and recorded on the mobile phone.

In addition, if you have creative needs, a mobile phone that supports high-power digital zoom can basically replace professional equipment, help you complete most of your shooting, and save a lot of money.

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