Kodak DCS500 manual Using Canon EZ, EG or E-Series Speedlites, What is A-TTL?

Using FP Flash Mode with EX-series Speedlites

1Turn on the camera’s Main switch, then turn on the flash.

2Make sure the flash is set for FP Flash, (Please refer to the Speedlite instruction book for details) and verify that the flash ready light is illuminated in red (indicating a full charge).

3Select the desired camera exposure mode (P, Tv, Av or M).

☛When the EX-series Speedlite is set for FP flash mode, the EX-series Speedlite will automatically switch to FP flash mode if the user-selected or camera-selected shutter speed is faster than 1/250 sec. This condition is indicated by the letter H in the viewfinder data display below the picture area.

4Select a focusing point using the focusing point selector button and Main dial, or set the camera for automatic focusing point selection (described in the next chapter) and focus the subject by pressing the Shutter button halfway down.

5Press the Shutter button completely to capture the image. Correct flash exposure of the subject is assured when the flash exposure confirmation signal lights up on the EX- series Speedlite. (Refer to the Speedlite instruction book for details.)

Using Canon EZ, EG or E-Series Speedlites

What is A-TTL?

The predecessor to E-TTL, A-TTL (Advanced Through-The-Lens) flash exposure control is used with EZ-Series Speedlites. Like E-TTL, A-TTL reads through the lens and concentrates its sensitivity on the area of the picture covered by the active focusing point. Unlike E-TTL, A-TTL controls flash exposure with a dedicated sensor that reads flash illumination reflected from the focal plane during exposure. A-TTL also uses a preflash, but unlike E-TTL, the preflash is used to calculate an aperture value based on the distance that light must travel from the flash to the subject. When set for Program mode, the camera compares the distance-based aperture value to the ambient-based aperture data calculated by the camera’s metering system, and selects the smaller aperture value of the two. This is designed to ensure accurate exposure of the subject in any lighting condition.

8-50