Modern phones with optical zoom usually have lenses with 3x-10x optical zoom. Trying to zoom in further than that should result in loss of quality, as you would technically be using digital zoom.

This macro shot compares a 3x digital vs 3x optical zoom (18mm to 55mm), shot with the same camera and settings. 3x Digital: Note the increased noise and loss of detail on the book cover.

With periscope lenses being a rather newer concept — early examples, such as Samsung's Galaxy S20 Ultra, launched in 2019 — it's important to note that optical zoom in smartphones isn't their ...