Canon PowerShot Pro 90 IS User Guide

Using an Externally Mounted Flash (Optional)   

Using Other Canon Flashes
• Since other flashes fire at full strength, set the

shutter speed and aperture accordingly. At
shutter speeds slower than 1/125 second
(maximum flash synchro shutter speed)
determine the appropriate aperture value
setting from the flash’s guide number and the
distance to the subject. You are also
recommended to set the white balance to the

 setting.

Press the shutter button halfway to
focus.

• The flash will indicate that it has finished

charging when its pilot lamp shines steadily. A
red   will show in the LCD monitor or
viewfinder if it is on.

Press the shutter button all the way to
shoot.

• The flash will not fire in 

,   or continuous mode.

• The Speedlite 380EX, 420EX or 550EX may not fire at the correct intensity if used

for bounced flash photography.

• The AEB mode cannot be used for flash photography. If the flash fires, only one

image gets recorded.

• Please note that proprietary high-voltage flashes with multi contacts or flash

accessories made by other manufacturers may cause a camera malfunction.

• A Canon Speedlite 480EG cannot be used with this camera because the flash will

not fire when mounted.

• The following functions can be used with a Speedlite 220EX, 380EX, 420EX or

550EX.

- Auto Exposure (Use the ETTL mode with a 550EX)
- FE Lock (Not available in   mode)
- Daylight Synchro
- Slow Synchro
- Flash Exposure Compensation (If a 550EX is used, the range figures on the

flash’s display panel will not display correctly. Use the camera’s flash exposure
compensation function instead.)

- Auto Zoom (Not available with the 220EX)