Being able to take pictures quickly does depend to a considerable extent on the quality of the sensor; getting all that data off of it isn't trivial; and analyz

Being able to take pictures quickly does depend to a considerable extent on the quality of the sensor; getting all that data off of it isn't trivial; and analyzing it to pick a focus and other settings is similarly hard to do quickly. And as it so happens, that's perhaps one area where sony is most ahead of the competition. Sure, their sensors have some slightly better technical characteristics in a lab (e.g. noise, dynamic range), but I kind of doubt they're enough to make a really noticeable difference compared to the competition. But they are really fast; e.g. show-off stuff like their relatively new RX10 gen 4 (see https://www.dpreview.com/products/sony/compacts/sony_dscrx10iv https://www.dpreview.com/products/sony/compacts/sony_dscrx10... ) have some fairly interesting features precisely because they're so fast. 24fps full phase detection autofocus? And it may well be able to do some image analysis to even detect, follow and focus on moving eyes at that speed? For frame of reference, canon's top end pro stuff (1DXm2) has around the same resolution, and just 16fps, and nikon's D5 "just" 14fps (not that they're really competitors, but just to give you an idea of what's technically high-end). Speed matters, and that's not really primarily a UI issue; it's to a large extent a technical challenge too. Shutter lag isn't new, and it's been an important stat for a loooong time. Even without any further information whatsoever, I'd be willing to bet that the lumia's shutter lag wasn't just a matter of poor UI or camera app software; but also one of sensor and other imaging limitations. TL;DR: if your old iphone had used your old lumia's imaging hardware, it probably would have been slow too.