The flash does not work well with the skateback.
LED flash distortion has been a well documented issue with all hard cases or backings that are raised from the surface of the phone. The problem is caused by the flash firing at a wide angle and reflecting off the inside of the back, causing interference.
Performance will vary greatly depending on distance from subject and ambient light.
If you would like to take flash photography of faraway subjects in pitch black you will experience distortion with the back on.
**this is a basic issue of physics with any hardcase**