How does the camera in the mobile phone zoom?

Camera zooming in mobile phones is generally digital zooming through interpolation algorithm.

That is to say, under the premise that the number of pixels of the photosensitive element is unchanged, a digital pixel is calculated out of thin air by interpolating two adjacent pixels. Because pixels are calculated, there are some errors with reality.

Therefore, theoretically, digital zoom can only enlarge the image, but not improve the resolution of the image.

This is the same reason that the mosaic will appear in the full-screen enlarged small picture.