Shulou(Shulou.com)11/24 Report--

With the exception of a few products such as Sony Xperia 1 IV, Samsung Galaxy Zoom, Asustek ZenFone Zoom and so on, the "optical zoom" of most phones is actually switching between different cameras. There is an image sensor behind each lens of the multi-camera phone, and both the sensor and the lens change when switching magnification. This situation is not only different from the optical zoom of the camera lens, but also different from the SLR / micro-single change of different lenses.

Therefore, the "optical zoom" on the mobile phone is precisely the "relay" work achieved by multiple fixed-focus lens cameras combined with digital processing.

* the telephoto lens on the Sony Xperia 1 III / 5 III can be switched between 70mm F2.3 and 105mm F2.8, which can be called dual focal length, but it is not a true optical zoom. To learn more about the "multiple", most mobile phones set the focal length of 23-27mm to 1 times (1.0x), so the ultra-wide angle is 0.4x, 0.5x, 0.6x, and the medium and long focal length is 2.0x, 3.0x, 5.0x. But this brings two problems:

-the definition of 1x is not the same, so 0.5x, 3x and 5x on different phones have different perspectives.

When a phone advertises a 10x zoom, it can be understood as having a 10x telephoto camera, or 10x zoom from ultra-wide angle to telephoto (for example, 0.5x-5.0x).

Therefore, rather than care about the lens several times, it is better to directly check / calculate the equivalent focal length.

The intermediate focal length is between two fixed-focus cameras (for example, from a 1.0x wide-angle main camera to a 3.0x telephoto camera), and there are a variety of operations to deal with the intermediate focal length:

The original method was digital zoom, which resulted in a continuous decline in image quality from 1.1x to 2.9x, and then a significant improvement in image quality from 2.9x to 3.0x.

After that, Android phones generally began to add "picture fusion" technology, such as using 1.0x and 3.0x cameras to take pictures at the same time in 2.9x, filling the 2.9x and 3.0x viewing angle gap with 1.0x outer circles. (this method is only suitable for taking pictures.)

Finally, since the vast majority of mobile phones use four Bayer sensors as 1.0x wide-angle main shots, they can output 4-pixel photos in high-pixel mode. So many phones with the main image function will take a high-pixel shot and then capture the central area to achieve zoom effect at 2.0x focal length (for example, taking the middle 12MP after shooting in 48MP mode, which is equivalent to 2x zoom)-this operation is sometimes billed as "lossless zoom".

▲ 's schematic diagram of the fusion zoom comes from the DXOMARK automatic switching even if it has a 2.0x and 3.0x telephoto camera, sometimes it will automatically switch to using the main camera or even ultra-wide angle to shoot. The reasons for this include: the subject exceeds the nearest focus distance, insufficient ambient light, unable to support the selected video shooting format, and so on.

Summary: the physical specifications and software settings of mobile phone cameras are already somewhat complicated, and the addition of technologies such as picture fusion and four Bayer also makes the working state of mobile phones more diverse. For the vast majority of users, we do not need to delve into how the phone actually works after the photo interface chooses zoom, but for friends who attach importance to images and have some requirements for picture quality, you still need to read the official propaganda and read some analytical articles to understand the best working mode of your mobile phone.

-- and the production of such analytical articles is also what ET has been doing in the past and will continue to be optimized and improved in the future.

This article comes from the official account of Wechat: camera Notes (ID:xjbiji), by Teng Fei et

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