Both phones took great shots here, but I'm giving the win to the OnePlus 6T for brightening up darker areas and revealing more detail, as well as giving off brighter colors than the Pixel 3.
In this sunset setting, the HDR mode on the OnePlus 6T produced a much better shot than the Pixel 3.
The OnePlus 6T also handled the setting sun better than the Pixel, and it's a more striking shot overall.
The difference is less pronounced on a bright sunlit day. The OnePlus 6T brightens up certain darker areas, which some might prefer. The Pixel 3 keeps certain areas darker, making for deep contrasts between bright and dark areas, which others might like.
This shows how the OnePlus 6T's camera can sometimes brighten up darker areas too much, creating a flatter and less dynamic photo than the Pixel 3's, which is obsessed with creating contrast.
I'm on the fence about this one. On one hand, I like the deeper colors and contrast of the Pixel 3's photo. On the other hand, the OnePlus 6T brighter colors makes for a more striking photo at first glance.
Overall, the Pixel 3's camera captures more accurate colors than the OnePlus 6T. The red on this flower was much closer to the Pixel's photo than it was on the OnePlus 6T.
But the OnePlus 6T sometimes did better with colors than the Pixel 3, too.
It's up to you, but from where I'm standing, it looks like the $800-$900 Pixel 3's reign as the top smartphone camera is put under heavy strain by a phone that starts at $550.