Full Auto Mode (Without Flash)
From above picture, its clear that Redmi Note 4 is better for more sharp and contrast control.
Now, lets see same photo captured with Flash
The original keyboard color was black, so here Redmi Note 3 performed well.
Now, about color, contrast & brightness this photo will surely make a sense
(Full auto without flash)
Same case, Redmi Note 3 giving high contrast and color then Redmi Note 4.
Lets see the outdoor picture quality
The Cactus color was green and Redmi Note 4 mixed the stone color with the plants and Redmi Note 3 also has less color then Redmi note 4. So, for more color Redmi Note 4 is better but it mixed the one object's color to another.
I choose to compare these devices because the both of them has Mediatek Chipset.
N.B. MIUI Team is working for improve Xiaomi Redmi Note 4 Camera performance, you may get update soon.
Now vote for your favorite camera device between these...
I am sure you will love Redmi Note 4...
I did not touch/modify/edit the images i shared in this thread.
I only compare still picture of rear camera of both devices.