>I checked the SB-600 manual. On page 50, "Wide Area >AF-assist" is a "feature" not a >"mode" of operation of the SB600. But on page 26, >it is listed as one of the available "flash mode" >settings for the SB-600.
It's not listed as a mode on page 26. It just happens to be on the drawing of the LCD. The mode selection is displayed on the upper left of the LCD.
>The line art on page 10, point 7, designates the Af >illuinators. the manual says nowhere that they are IR (or >visible red). I learned that from Stan, and that they are >also (dimly) visible red.
As far as I've been able to ascertain, there's no IR from the AF-Assist. The AF system of the camera is a visible-light system. They're simply red lights. If it was infrared, you wouldn't see the light. And since there is visible light, the AF system can see it as well and use it for focus. That's said, if anyone knows for sure that it's otherwise, I'd appreciate a link to that information.
>Also, if the SB-600 is set to AF-assist, and the camera's >built-in falsh is not deploayed, then there will be no flash >to illuminate the capture, rgiht? No need t ohold in the fn >button. Right?
There's no setting the SB-600 to AF-Assist. The only modes of operation are TTL-BL, TTL, and M. As you say, AF-Assist is a feature, and there's no option to disable the flash when the unit is turned on. If it's mounted on the camera and it's turned on, it flashes (in M,A,S,and P modes.) As far as I'm aware, the only way to use the AF-Assist without the flash firing is to use the Flash-off setting of Fn and hold the Fn button.