In addition to traditional optical wireless transmission, the Speedlite 600EX-RT facilitates radio controlled, two-way wireless transmission up to 98.4 feet, among up to 5 groups with a total of 15 individual Speedlites. Communicating on 2.4 GHz frequencies, the Speedlite 600EX-RT does not have the same directional limitations of traditional wireless optical transmitters. 15 transmission channels are available, selectable manually or automatically, and radio transmission IDs can be set to prevent misfiring in the event of signal interference on the same channel.
The Speedlite 600EX-RT has an improved guide number of 197ft. (60m) at ISO 100. It offers 20mm to 200mm coverage, and when the extendable wide panel is pulled out, flash coverage moves as wide at 14mm. Plus, to maximize power and minimize energy consumption, the Speedlite 600EX-RT can be directed to zoom in accordance with the cameras image sensor size (full-frame, APS-H and APS-C).
The flash head is more rugged and durable than its predecessor and a redesigned hot shoe contact ensures seamless communication. Dust and water resistance has been improved significantly as well: all moving parts and areas surrounding the flashes display and buttons are sealed for uninterrupted performance in harsh conditions. A new dust and water resistant adapter for the mounting foot creates a dust and water resistant seal between camera and flash.
Working in conjunction with EOS SLR's, the Speedlite 600EX-RT automatically provides illumination using its built-in AF assist beam. This means more accurate AF, faster, even in dark or low contrast situations, with all lenses 28mm or longer. Compatible with the AF frame of all EOS cameras, the Speedlite 600EX-RT even works perfectly with the 61-Point High Density Reticular AF found in the EOS-1D X and the EOS 5D Mark III.
The Speedlite 600EX-RT features an all-new dot matrix LCD panel (172 x 104 dots). This new LCD displays Flash status, wireless configuration and all flash settings with more detailed information in comparison to previous systems. With its new screen combined with backlit operation buttons, the Speedlite 600EX-RT is as easy to operate in the dark as in daylight.
The Speedlite 600EX-RT features a new color filter holder. By placing a color filter over the front of the flash head, the color temperature of the flash can be made to match that of the ambient light. Color information and light output decrease can be transmitted from the Speedlite 600EX-RT to the camera for proper white balance and exposure.
Options include Flash exposure bracketing controls, modeling flash, test firing controls, AF assist control, power and energy saving features, beep and much, much more. Personal functions, like LCD panel illumination color and Master/Slave configurations are also easily set on the Speedlite 600EX-RT
The head can be angled 90° up, 7° down and can rotate 180° left and right. A bounce lock with release button helps things stay in place. Additionally, when the flash head is positioned front and up 90°, the Speedlite 600EX-RT features a catch light panel to create catch light in the eyes of the subject for a more expressive look