The hidden limitations of your phone's telephoto zoom camera

In 2016, phones with more than one rear camera were a rarity. In 2019, it is hard to find one that doesn't have at least two lenses at the back. Apple, Samsung, LG and Huawei are just some of the companies equipping its best phones with dual, triple, or even quadruple cameras, giving their owners the kind of creative freedom we could once only get out of a dedicated camera with advanced optics.

But here's the thing: all of these additional cameras are not necessarily better cameras. A monochrome secondary camera is more sensitive to light, but it shoots in black and white only. A wide-angle ...