Canon 550EX manual Focus the subject

Stroboscopic Flash

2 Use the following formula to calculate the required shutter speed.

Flash count ÷ Firing frequency = Shutter speed

Example: If the flash count is 10 and the firing frequency is 5 Hz, the shutter speed will have to be at least 2 sec.

10 ÷ 5 = 2

• If the flash count display is , the flash will keep firing until the shutter speed ends or until the maximum number of continuous flashes (as indicated in the table on page 122) is fired.

3 Focus the subject.

• To set the exposure settings, see “Manual Flash Mode” on page 93.

4 Check that the icon is displayed in the viewfinder, then take the picture.

To prevent overheating and deterioration of the flash head, do not use stroboscopic flash for more than 10 frames in rapid succession. After 10 frames, allow the 550EX to cool for at least 10 minutes.

•Stroboscopic flash is most effective with highly reflective subjects in front of a dark background.

•Using a tripod and Remote Switch are recommended.

•Using an external power source is recommended for stroboscopic flash.

•Stroboscopic flash cannot be used at a flash output of 1/1 or 1/2.

•buLb can also be used with stroboscopic flash.

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