Nikon D100 Product Manual - Page 106

Taking Photographs-Flash Photography Flash Photography Using Built-in and Optional Speedlights The D100 is equipped with a Guide Number 17/56 (ISO 200, m/ft; Guide Number at ISO 100 is 12/39) Speedlight with a flash angle wide enough to cover the field of view of a 20-mm lens. With a CPU lens, the built-in Speedlight supports D-TTL flash control for flash photographs with a natural balance. The built-in Speedlight can be used not only when natural lighting is inadequate, but to fill in shadows and backlit subjects or to add a catch light to your subject's eyes. Flash Angle While the built-in Speedlight can cover the field of view of a 20-mm lens, it may not be able to light the entire subject with some lenses or at some aperture settings. ISO Auto If a Speedlight is used when Custom Setting 3 (ISO Auto) is on, sensitivity (ISO equivalency) will be fixed at the value selected by the user. Using an Optional Speedlight If an optional Speedlight is used with spot metering, Standard TTL flash for digital SLR will be used. If the built-in Speedlight is raised when an optional Speedlight other than the SB-50DX is attached, the optional Speedlight will not fire. If an SB-50DX is set to manual in the bounce flash position, both the built-in Speedlight and the SB-50DX will fire. 94