Quantum Q Flash X5DR Digital Full TTL Dedication for new digital and film cameras Automatic Fill Mode: This mode allows setting fill flash ratios when used with one of the new QTTL adapters. Fill-flash ratios can be controlled even for cameras that do not have fill-flash capabilities! Automatic Sensor Limit: This option limits the distance the Qflash sensor "sees" when in Auto mode, This prevents subject "blow out" A Qflash 4 with QTTL adapters lets you use Sensor Limit in Program, Auto and Auto/fill modes, while the flash exposure tracks the camera f/number settings Quick Turn off: For temporary turning off the flash Twice as many Program Modes