I was really impressed with the image quality of the sample of the Samsung Galaxy S8 that I've seen on YouTube. When I analyze the image quality, I am usually checking the dynamic range, the color reproduction, the video stabilization, sharpness, image artifacts, low-light performance, how severe is the shutter rolling effect, etc. I've searched YouTube for Galaxy S8 sample images and didn't find a lot, but I came across mobilissimo.ro YouTube channel which posted lots of video camera samples that really showcase the sensor's capability.
I have to say that I really liked the image quality. The sample videos taken in daylight. I am talking about the rear-facing camera, although there is one video showing the front-facing camera as well. The image quality is nothing but superb, with beautiful vivid colors, sharp details, surprisingly good dynamic range and good electronic video stabilization.
This is exactly the video quality I am expect to get from a high-end mobile phone like the Galaxy S8. I'm just amazed how well those tiny mobile phone camera sensors can perform.
I usually prefer to also see videos that the photographer doesn't pan the phone every second so I can get a good look at the image quality. There is one good video with slow panning movement, I think it's the last one, so you can get a good look at the details.
The color reproduction is excellent. The image look vivid yet still very natural which is really important. You can see how beautiful the green of the trees and the blue of the sky look, just stunning. Even a simple street view looks interesting when the color is boosted by a slight degree. I prefer this to a more flat look.
You can also see how fast the autofocus is in the second video. Going from long distance to doing a closeup on a flower is seamless, fast and smooth. The Galaxy S8 feature a 12MP Dual Pixel camera. This means that for each photosite the sensor has two photodiodes and this allows the camera to shift focus amazingly fast. This is the same technology that Canon has introduces a long time ago and I remember that it just revolutionized the autofocus in videos for digital cameras back then. It's great to see this technology in mobile phone cameras as well.