I thought Stan's reference to IR3 LEDs was to three infra-red LEDs, but I see that it is probably to Pacific cybervision's IR3 LED, the current generation, & presumably visible. Yes?
But I also thought that using the SB-600 for "wide Angle AF Assist feature" (not "mode") avoids the white light for the actual shot capture. But Gray_star says it does not; that it is necessary to set the fn button to FLASH OFF and press it for each shot. to avoid capture illumination from the SB-600, which would be rather tedious.