How would the camera know the focal length of an A series lens? That information is not transmitted to the body. I suspect P-TTL doesn't work as well with A series or earlier lenses. There is less information to work with.
-- Bruce Wednesday, April 5, 2006, 8:14:07 AM, you wrote: GD> The distance information is used in P-TTL flash metering as well as GD> in matrix metering when you set the option to link AF and AE systems. GD> It is also used to select preset modes when you set the DS into Auto GD> Picture mode ... the camera knows what lens you're using and what GD> distance your subject is and makes a guess as to overall scene type GD> on that basis. GD> P-TTL works with A series lenses without distance information too: it GD> simply defaults the distance information with a pre-determined GD> constant based on focal length. GD> Godfrey
