The following instructions will help you fix the Rear Camera being too dark on Windows 10.
1.) In the Search Box type in Device Manager and press enter or touch the Device Manager Icon in the list
2.) Open up Imaging devices and remove the Intel Signal Processor by right clicking or holding down touch and click/touch Uninstall. Check the box to Delete the driver software for this device and press ok.
3.) Scroll down to System Devices and Expand by double clicking. Use the same removal process as before and remove the gc0310 Camera and the hm2056 Camera in the list. Make sure to check the delete the old drivers checkbox.
4.) Reboot the tablet
5.) Download the new drivers from this link and extract them to your desktop. Challenger II Camera Drivers
6:) Inside the Extracted folder There is a file named Install_Driver.bat. Right click the file and hit run as administrator. Once done reboot the Tablet and the Cameras will be fixed.