Update | 3x optical zoom for the Galaxy S20 and S20+? Not quite
Update: After a closer look at Samsung's technical spec sheet, we've found out that the Galaxy S20 and S20+ do not, in fact, even offer anything close to the 2.5x optical zoom originally estimated here. The phones only have optical zoom of about 1.06x—non-existent for all intents and purposes. Instead, the telephoto cameras of the phones use a 64 MP sensor with a wide-angle lens and crops into the image to offer Samsung's "3x hybrid optical zoom".
Samsung's new Galaxy S20 phones have been heavily marketed for their camera prowess. The S20 Ultra goes all out with a class-leading 108 MP camera, while the S20 is pushed for its 64 MP camera, even though its main camera is a 12 MP one. Samsung also advertises the S20 and S20+ as capable of 3x optical zoom, but that may just be a tad misleading.
In Samsung's technical spec sheet, the S20 and S20+ are listed with 30x combined zoom, with 12x digital zoom. Some simple math shows us that equates an optical zoom of 2.5x, not 3x as Samsung advertises. Essentially, the phones have a lossless zoom of 2.5x, then uses a 12x digital multiplier to reach the 30x zoom that's advertised. It's likely that the 3x zoom range in the camera app simply uses the 2.5x zoom lens, then crops out the edges of the image.
It's not a big deal, we must clarify. The final image is still lossless, although it sacrifices the field of view to achieve it. Samsung never calls it 3x optical zoom, either. The official website labels it "Hybrid Optic Zoom 3x". It's not the first time a company has done this either. OnePlus advertised 2x and 3x lossless zoom for the OnePlus 6 and OnePlus 7 Pro, while the phones only truly had about 1.6x and 2.2x optical zoom respectively.
The S20 Ultra has 5x optical zoom, then uses 20x digital zoom to achieve its 100x "Space Zoom".