There are two ways for zooming, optical zoom and digital zoom.

For example, when you want to take the subject up, the optical zoom actually extends the distance between two lenses, but the digital zoom processes in the program.
Of course the optical zoom is better in terms of image quality.

Since smartphones are thin, optical zooming was difficult.

Samsung’s unique method is putting some lenses inside the pen (stylus).
You can check the image on smartphone display.

If this method works well, I guess the sales of digital camera will more decrease.