your 5-megapixel version will focus in on what you want to quickly share, but you can go back to the larger version to discover something you might have missed in the surrounding area.
But digital zoom is digital zoom and won't replace what a real zoom lens can do. Among the three phones, only with the Zoom was I able to make out faces of band members at a recent concert in New York.
Both the Lumia and the Zoom offer a greater range of manual controls than typical camera phones. A Grip attachment for the Lumia also has a hole for screwing the phone onto a tripod. But if I'm going to take special shots requiring manual controls or a tripod, I'm also likely to have my SLR, which has a powerful lens that can't possibly be squeezed into any smartphone.
I came to appreciate the iPhone's camera while taking some close-up shots of bees pollinating a bed of flowers. The bees were moving too quickly for most of my cameras, including the SLR, to get decent, focused shots. But the iPhone 5 and later the 5S somehow managed.
The Lumia also wasn't practical for frequent shots. With a lot of megapixels to store, it takes time for the camera to be ready for the next shot. There was also a delay in capturing shots. I tested the various cameras by shooting moving vehicles. With the Lumia, cars meant to be in the center were near the edge or out of the frame by the time the image was actually captured.
As for the Zoom, it's too bulky to carry around. Even with the lens receded, the Zoom is still more than three times thicker than the iPhone at the thickest point, the lens.
The iPhone 5S isn't always as good as the Lumia in low-light settings or the Zoom for far-away shots. It also can't match the SLR for special shots that need manual controls.
But it doesn't matter if the iPhone won't always give you the best picture as long as it's the best at giving you good pictures consistently.