Dynamic range is a measure of the camera's ability to record extremes of brightness and darkness without losing detail in either. It's measured in EV (exposure values) and the higher the number the better. We test dynamic range using DxO Analyzer hardware and software in laboratory conditions.
JPEG dynamic range analysis: The X70 doesn't score as well as the competition at many sensitivity settings, but the images it generates have pleasant contrast. We've seen this before with JPEG images from Fuji cameras.
Raw (converted to TIFF) dynamic range analysis: While highlights aren't lost quickly, with the default raw file conversion the X70 scored much lower for dynamic range than the competing models, indicating that there's a lower tonal range.