Phones with 5x periscope telephoto

Phone zoom is three different things and they are easy to confuse: optical zoom magnifies with the lens itself and loses no detail; sensor-crop zoom magnifies by cropping into the middle of a high-resolution sensor and stays clean up to a point; digital zoom enlarges the image and fills the pixels in between by computation.

A periscope telephoto folds the light 90 degrees with a prism and runs it lengthways through the body, so that a long focal length fits inside a phone. That is how real optical magnification is achieved without making the phone thicker. The 5x on this page is the ratio the periscope reaches optically — up to that point, no detail is computed.