In mobile phone photography, why is the picture quality particularly poor after zoom shooting?

Once the camera on the mobile phone is lost, there can be no optical zoom problem. Its lens is fixed. You can also call it "fixed focus lens". Nowadays, dual-camera and triple-camera mobile phones are actually equipped with several lenses with different focal lengths, and several different "fixed-focus lenses" are installed to achieve zooming by changing the lenses. So, can't the phone zoom? Yes, it can zoom. Its zoom is called digital zoom.

In the past, the parameters of the card machine were described as follows: optical zoom and digital zoom. Needless to say, optical zoom is realized through the lens, while digital zoom is realized through the internal software of the camera, so enlarge the picture! So is the zoom of the mobile phone! Think about it, if you enlarge a picture on the computer, is it a mosaic? A truth. The mobile phone has poor photo-taking ability, and zooming in again means zooming in again.

That would be even worse. It is normal that the picture quality is particularly poor. Digital zoom is to zoom in the optical zoom lock, and then zoom in locally by digital method. Although digital zoom can effectively enlarge the image, it will reduce the image quality and consume the resolution, but in the camera phone with limited space, only providing digital zoom function is the mainstream specification; Lossless zoom is more of an AI algorithm. Optical zoom is the most traditional zoom method, and it is also a way that the image quality changes little after real zoom.

The principle is the same as the zoom lens of a camera, which is focused by a concave lens and a convex lens. After enlarging 100%, the details of the two photos are exactly the same except brightness, and the effect of the second enlargement of the picture on the right is exactly the same as that on the left, so it can be confirmed that digital zoom is basically to enlarge and crop the photo. Therefore, in order to reduce the image quality damage after amplification, it is still necessary to add lens products to start with optical zoom.