Powerful, multifunctional high-end Speedlight designed to fulfill the requirements of professionals. Supports radio-controlled Advanced Wireless Lighting, offering more flexibility in wireless multiple-flash photography than a conventional optical-controlled system. Compatible with unified flash control, which provides access to flash settings from the camera and a computer with Camera Control Pro 2 installed. Powerful guide number of 34.5 m/113 ft at 35mm or 55 m/180 ft at 200mm (ISO 100, 23°C/73.4°F, in FX format, standard illumination pattern).