What Supersaf showed in his comparison is pretty accurate, but doesn't tell the whole story about how great the camera is. I came from an iPhone 7 and went to the iPhone 8 Plus, and the difference is quite something. Not just because I get optical zoom and portrait mode now, but even just the wide-angle lens is definitely notably improved over the iPhone 7. There's more detail and less noise when taking photos in low-light situations, in day-light everything seems sharpers and more colorful too. Supersaf claims the colors tend to go more into Samsung's 'way' by being oversaturated and all. I disagree with that. I think the colors are simply more accurate than they used to be. But they're not oversaturated at all.
At least not from my perspective. I may not be a professional photographer of any sort, but neither am I trying to justify the 'small' upgrade over the iPhone 7. The iPhone 8 Plus has a great camera, period. No matter if you come from an iPhone 7 (Plus) or any older device. It's getting closer to DSLR photography. Obviously it's never gonna get that far, but things like Portrat mode and optical zoom really do help with getting much greater photos without being an actual photographer. That's what I like so much about the iPhone.