170lThe Built-in FlashThe built-in flash has a Guide Number (GN) 17/56 (m/ft, ISO 200,20 °C/68 °F). It supports i-TTL balanced fill-flash for digital SLR,which uses monitor pre-flashes to adjust flash output for balancedlighting not only when natural lighting is inadequate but whenfilling in shadows and backlit subjects or adding a catch light tothe subject’s eyes. The following types of i-TTL flash control aresupported:D ISO Sensitivityi-TTL flash control can be used at ISO sensitivities between 200 and 3200.At values over 3200 or under 200, the desired results may not be achievedat some ranges or aperture settings.i-TTL balanced fill-flash for digital SLR: Speedlight emits series of nearlyinvisible preflashes (monitor preflashes) immediately before main flash.Preflashes reflected from objects in all areas of frame are picked up by1,005-segment RGB sensor and are analyzed in combination with rangeinformation from matrix metering system to adjust flash output fornatural balance between main subject and ambient backgroundlighting. If type G or D lens is used, distance information is includedwhen calculating flash output. Precision of calculation can be increasedfor non-CPU lenses by providing lens data (focal length and maximumaperture; see pg. 196). Not available when spot metering is used.Standard i-TTL flash for digital SLR: Flash output adjusted to bring lighting inframe to standard level; brightness of background is not taken intoaccount. Recommended for shots in which main subject is emphasizedat expense of background details, or when exposure compensation isused. Standard i-TTL flash for digital SLR is activated automatically whenspot metering is selected.
