On Dec 20, 2005, at 4:25 PM, Godfrey DiGiorgi wrote:
TTL flash metering is supported by the D (built-in flash when using lenses that do not support P-TTL metering) and by the DS/DS2 when using a compatible dedicated external flash unit. Due to the nature of TTL flash metering, it must be reading "off the film/sensor" since it is determining light levels dynamically at the time of exposure.
None of the DSLR cameras use off the sensor metering. This is due to problems with the reflectance characteristics of the sensors. They do TTL metering by measuring a preflash.
Bob
