Canon's 600EX-RT Speedlites are my go to on and off camera flash units, and I love them. Light, portable and they pack quite a punch. I was so excited to get my hands on these because they have radio transmission capability built in. The idea that you no longer need to fumble about with an external transmitter and receiver (pocketwizards) was super attractive to me. One less piece of external gear means lighter, more transportable and more time efficient improvements.
overall the system is easy to use. for all off camera flash capabilities just mount the Canon ST-E3-RT Speedlite Transmitter to the hot shoe sync up all the flashes and BAM, you're ready to go.
Saturday's outdoor reception was the ultimate test for radio transmission because outdoors there are no walls or ceilings for the signal to bounce off of. I tested them during the toasts and a video montage, capturing the couple's reactions. I had the camera up to my eye for 20 minutes straight aimed at them to capture these emotions and neither flash failed once. I was so thankful to have the off-camera flash in the background. Without it, these photos would have been so flat with a black void behind the subjects.
Complete with built-in radio transmission wireless functionality, the Speedlite 600EX II-RT sits at the top of Canon's on-camera E-TTL / E-TTL II compatible flash lineup with a powerful guide number of 197' at ISO 100 and 200mm. This revision improves continuous flash performance by 1.1-1.5x, or up to 2.0x with optional battery pack, simplifies the menu system for faster operation, and includes a specially designed bounce adapter, a hard color filter, and an updated soft case. The two-way 2.4 GHz radio system provides added reliability and a range up to 98.4' among up to 5 groups with a total of 15 individual Speedlites. This system also does not need direct line-of-site like traditional optical-based transmission and will work through obstacles.
For added coverage and functionality, the flash's zoom head can reach from 20-200mm, with the option for wide 14mm coverage when the built-in diffusion panel is used. Also, the unit can tilt from -7 to +90° and rotate 180° either left or right for complete bounce capabilities. On the back of the 600EX II-RT is a backlit dot-matrix LCD panel that displays the status and allows users to easily access and change settings. Additionally, the flash is durable with a redesigned contact construction and improved dust and water resistant sealing.
Other capabilities of the 600EX II-RT include a stroboscopic mode as well as high-speed, first and second curtain sync settings for more control over your image's final look. The flash is powered by 4 AA batteries and has a port for an optional external power pack. The rated recycle time is 0.1-5.5 seconds, but can be sped up to 0.1-3.3 seconds in Quick Flash mode. It comes with a bounce adapter, a hard CTO filter set, a mini stand, and an updated soft case that holds the flash and accessories.