It turns out that Samsung is using two different sensors for the back and front camera in the Galaxy S8 and S8+. Units have been spotted using a Sony IMX333 sensor and a S5K2L2 ISOCELL sensor made by System LSI, a subsidiary of Samsung. The same goes for the new 8MP autofocus front-facing camera - underneath the optics is either a Sony IMX320 unit or an ISOCELL S5K3H1. The different cameras share the same specs across the board though. No matter if you get a Sony or a Samsung-made main camera you still have a 1/2.55" 12.2MP sensor with Dual Pixel autofocus and naturally the optics...
Source: http://www.gsmarena.com/samsung_galaxy_s8_uses_two_different_camera_sensors-news-24316.php
