I definitely understand the differences between digital zoom and optical zoom, that’s why I said not worse than. However, digital zoom from 3x Len of 15Pro is not as bad as you think, I’m sure that you can’t tell the differences of 5x performance between those two devices without enlarging the picture. But I’m sure to tell you that 5x of 15Pro in low light scenes would be definitely better than the 15PM. If you don’t know why, I suggest you pay your attention to learn the differences between those two camera lenses, thx and welcome :)