The Speedlite 550Ex can use any of the following two external power sources. For details, refer to the instructions of the respective external power source.
Flash exposure compensation with the 550EX can be set up to +/- 3 stops in 1/3-stop increments (or 1/ 2 -stop increments with some cameras). You can also use flash compensation in combination with normal exposure compensation (to control the background's exposure level) in a flash picture.
As shown in the figure below, the wireless E-TTL autoflash system described as an example consists of a sender unit set to sender flash OFF and two receiver units. The receiver ID of the receiver unit on the camera's left is A The receiver ID of the receiver unit on the camera's right is B
You can set a different output for each receiver unit (A, B and C) as follows. 1. On the sender unit, press the <MODE> button and select M 2 . Press the <SEL/SET> button and select <RATIO)
Three bracketed flash shots can be taken: Correct exposure, decreased exposure and increased exposure. The three shots can be bracketed up to +/-3 stops in 1/3-stop increments (1/ 2 -stop increments if the camera enables only 1/ 2 -stop increments). This is called FEB (Flash Exposure Bracketing).
In the manual flash mode, you can set the flash output from 1/1 (full) to 1/128 power in full-stop increments To prevent overheating and deterioration of the flash head, observe the following limits for continuous shooting with flash: (1) At 1/1 or 1/ 2 output Max. 15 continuous flash shots
1. As with studio flash units, you can set the receiver units flash output yourself for wireless or manual flash photography 2 . For wireless manual flash photography with Wireless Transmitter ST-E2. On a receiver unit with the wireless selector set to <receiver>, press the <MODE> button for at least 2 sec.
