What's the difference between digital zoom and optical zoom?

Digital zoom is an electronic enlargement of a picture, which enlarges some pixels on the original CCD image sensor to the whole picture. Optical zoom relies on the structure of optical lens to achieve zoom, that is, the scene to be shot is enlarged and reduced by the movement of camera lens. The larger the optical zoom coefficient, the farther the scene is photographed.

DigitalZoom, called digital zoom in English, enlarges the area of each pixel in a picture through the processor in a digital camera, so as to achieve the purpose of enlargement. This technology is like enlarging the area of a picture with image processing software, but the program is executed in a digital camera. Some pixels on the original CCD image sensor are enlarged by interpolation, and the pixels on the CCD image sensor are enlarged to the whole picture by interpolation algorithm. In fact, digital zoom does not change the focal length of the lens. Principle: Use software to judge the color around existing pixels, and insert pixels added by special algorithm according to the surrounding color.

The English name of Optical Zoom is Optical Zoom, and digital cameras rely on optical lens structure to achieve zoom. The optical zoom mode of a digital camera is similar to that of a traditional 35mm camera, that is, the scene to be shot is enlarged and reduced by moving the lens. The larger the optical zoom coefficient, the farther the scene is photographed.

Extended data:

Advantages and disadvantages of digital zoom:

Digital zoom camera is not only an optical product, but also contains related elements or pixels of digital photos. When the central part of the image captured by CCD or CMOS chip is enlarged or reduced by internal program, the adjacent pixels are obtained by complex matrix, and the image is enlarged (or interpolated) by a method similar to cell regeneration, thus generating digital zoom. The greater the degree of interpolation, the greater the digital zoom.

Excessive interpolation will lead to graininess and pixelation. This often happens on the film of a digital camera, so a large degree of digital zoom is needed. When you enlarge a traditional photo, you will find that some previously invisible elements are gradually blurred ―― sometimes it is better not to enlarge the photo.

This situation also applies to digital zoom photography, and blur is eternal in the pixel world. When digital zoom generates an image, the computer is looking for pixels, but the computer is not smart enough to only look for "good" pixels and remove "bad" pixels. It will only make the photos more and more blurred. Therefore, the higher the digital zoom, the more blurred the photo. Of course, you can also use some software to deal with this situation, but this is another matter.

Baidu Encyclopedia: Optical Zoom

Baidu Encyclopedia: Digital Zoom