A quick comparison of the iPhone 6 Plus and the iPhone 7 Plus following a casual stroll around a lake after Thanksgiving dinner.
The original iPhone had a 960 x 720 pixel camera, which means the iPhone 6 Plus camera, at 3264 x 2448 pixels, and iPhone 7 Plus camera, at 4032 x 3024 pixels, are essentially either 11.6 or 17.6 original iPhone cameras at once. As carrying around 17.6 cameras seemed inconvenient, we (me) took a couple of photos with my iPhone 6 Plus, then snatched someone else’s iPhone 7 Plus to take more photos.
The iPhone 6 Plus photo:

The iPhone 7 Plus photo:
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These are not exactly the same photo because I moved around, didn’t think of using the iPhone 7 for several minutes, etc. But then it also occurred to me to stand in the same place as the second photo and use the second lens on the iPhone 7 Plus to take a 2X view:

As it got darker, it became much harder to see, much less take photographs. But the iPhone 7 Plus seemed up to the challenge:

I also took a photo of some ducks, but it was quite dark, and the photo was poor. And yet — I discovered later, looking at the photo on a large computer monitor, that the “ducks” were clearly Canadian geese. This wasn’t clear to the eye, but the iPhone 7 Plus had no problem showing the distinctive plumage.
The iPhone 7 Plus may be an incremental improvement of the iPhone 6 Plus, but the increments are collectively quite impressive. Oh, it also makes phone calls, and is a great GPS.