[. . . ] E English Edition INSTRUCTIONS E Thank you for purchasing a Canon product. The Canon Speedlite 550EX is a powerful, high-output flash unit featuring ETTL (Evaluative-Through-The-Lens) autoflash control. It can be used as an oncamera Speedlite or as a master or slave unit in a wireless, multi-Speedlite system. When used with Type-A cameras (listed below), the 550EX obtains natural-looking flash pictures by balancing the flash output and existing light. The 550EX also enables high-speed sync (FP or Focal-Plane flash), FE (Flash Exposure) lock, FEB (Flash Exposure Bracketing), bounce flash and area AF-assist. [. . . ] · To indicate that a flash ratio has been set, A:B will remain displayed on the master unit's LCD panel. 6 Follow the basic procedure for wireless E-TTL autoflash picturetaking on page 60 and take the picture. · During the setting procedure, A:B and blink for 8 sec. To make them blink again (so you can alter the flash ratio), press the < > button again. · The flash ratios corresponding to the positions on the flash ratio scale are shown below. (5. 6:1) (2. 8:1) (1. 4:1) (1:1. 4) (1:2. 8) (1:5. 6) · Flash ratios of A:C and B:C cannot be set. After you set the flash ratio and the flash ratio bar is displayed, you can still change the A:B flash ratio with the < > and < > buttons. 65 Wireless E-TTL Autoflash With Flash Ratio ON G Setting the Flash Ratio for Three Slave Units: A, B and C With three wireless slave units, slave unit A is the main flash, slave unit B is the fill flash, and slave unit C is a supplemental flash. Thus, slave units A and B serve to illuminate the subject for a proper exposure while slave unit C illuminates the background to eliminate shadows. Even with three slave units, the E-TTL autoflash system controls the flash to obtain a correct exposure. In addition to setting the A:B flash ratio, a flash ratio of (A:B):C can also be set. This is done by adjusting slave unit C's flash exposure compensation amount. 15 m / 49. 2 ft C 10 m / 32. 8 ft For indoors A B 12 m / 39. 4 ft For outdoors 80° 8 m / 26. 2 ft 66 Wireless E-TTL Autoflash With Flash Ratio ON The following wireless E-TTL autoflash procedure is for a master unit with three slave units. This procedure sets the A:B flash ratio and the flash exposure compensation amount for slave unit C. · The flash ratio range for A:B is the same as when only two slave units are used. · Flash exposure compensation with slave unit C can be set up to ±3 stops in 1/3 or 1/2-stop increments. · The slave ID of the slave unit on the camera's left is A. · The slave ID of the slave unit on the camera's right is B. · The slave ID of the slave unit illuminating the background is C. · The camera (attached with the master unit) and three slave units are properly positioned for the subject. 1 On < the master unit, press the > button and select . · Pressing the < > button changes the selection in the following loop: (Off) > 2 Press the <A:B. button to select ON · ON A:B will blink. 3 Press the < to select · > button again ON A:B C. A:B C will blink. 67 Wireless E-TTL Autoflash With Flash Ratio ON 4 Press the < · blink. > button. (flash ratio bar) will A:B and > or 5 Press the < ratio. < the A:B flash > button to set · Press the < > button to move the flash ratio bar to the left, or press the < > button to move it to the right on the flash ratio scale. 6 Press the < 7 Press again. 8 Press again. · > button. A:B:C · The flash ratio bar and remain displayed. the < > button · The for A:B will blink. · To change the flash ratio, repeat steps 4 to 6. the < > button exposure C and the flash compensation display will blink. > or < > button to set 9 Press the <exposure compensation the flash amount for C. 68 Wireless E-TTL Autoflash With Flash Ratio ON < 10 Press the setting. register the > button to · The flash ratio bar and A:B:C remain displayed. · To change the flash exposure compensation amount, repeat steps 8 to 10. 11 Follow the basic procedure for wireless E-TTL autoflash on page 60 and take the picture. · Even if you have slave units A, B, and C, if only A:B is selected, slave unit C will not fire. · If slave unit C is used to illuminate the subject directly, overexposure may result. G Slave Groups A Slave Group Multiple slave units having the same slave ID will be recognized and controlled as one slave group. The group will be treated as one slave unit. · In the left figure, the slave ID is A for all three slave units. They will be controlled as slave unit A even as a group. 69 Wireless E-TTL Autoflash With Flash Ratio ON G Wireless High-Speed Sync (FP Flash) After setting up the wireless flash system with one or more slave units, you can enable wireless high-speed sync by setting on the master unit. · You need not touch any controls on the slave units. [. . . ] If such changes or modifications should be made, you could be required to stop operation of the equipment. This equipment has been tested and found to comply with the limits for a class B digital device, pursuant to part 15 of the FCC Rules. These limits are designed to provide reasonable protection against harmful interference in a residential installation. This equipment generates, uses and can radiate radio frequency energy and, if not installed and used in accordance with the instructions, may cause harmful interference to radio communications. [. . . ]