Multiple cameras make better use of the horizontal physical space inside smartphones. ---- For a long time, before smartphones started having many cameras, manufacturers had to make compromises for one camera for everything. Examples in 2013 and 2014: While other manufacturers went for higher resolutions (megapixels), HTC brought their *One M7* and *One M8* with only four megapixels. But that allowed a much larger surface size per pixel on the image sensor. Bigger pixels allow capturing more light in the same time at the same light sensitivity, thus allow brighter pictures with the same ISO or exposure setting (or same brightness with lower ISO or exposure setting). In 2014, HTC had to forego 2160p (4K) video recording on the HTC One M8 due to insufficient image sensor resolution. One year later, HTC flipped over to the high end megapixel side, with 20.7 megapixels on their *One M9*. As expected, the low light performance suffered. But megapixels, also for budget compact cameras, is good for markting. But now, manufacturers can have multiple cameras with different ranges of strengths and weaknesses, including: * Balanced (main camera) * Tele camera or very-high megapixel camera (weakness: low light) * Macro camera (near shots) * Wide camera (wide field of view) * Non-colour camera (strength: low light: triple light per same pixel size, because no colour subpixels needed) * Thermal camera (Cat S60) * …and maybe an additional camera or infrared laser that assists with autofocus. Also, the software has improved. With the support of the orientation sensor and gyroscope, “Night mode” is able to calculate the best, lowest-noise, highest-detail image out of data captured while holding the camera as steady as possible in darkness. (But software-based “noise reduction” is just a gimmick that irreversibly washes out details from the image during post-processing just to make it appear less noisy. I hope manufacturers use that as little as possible.)