It seems to me that so called advanced P-TTL is a cut down version of proper TTL. It cuts the flash off a a predetermined time based on the preflash exposure measurement, rather than cutting it off due to measuring it during the actual flash exposure.
Or am I missing something? Nick -----Original Message----- From: "Godfrey DiGiorgi"<[EMAIL PROTECTED]> --- John Francis <[EMAIL PROTECTED]> wrote: > But you're still basing your agument on the (apparently unwarranted) > premise that the *ist-DS *does* disable TTL flash for all non-AF lenses. > According to other posters here, that simply isn't the case. Right. The DS body's built-in flash does ONLY P-TTL automation, so if a lens is fitted that doesn't provide the aperture information, it simply goes to a full output, simple manual flash. Distance means nothing at all. P-TTL works fine with A series manual focus lenses when set to the A position on the aperture ring. TTL (as opposed to P-TTL) is fully supported with the dedicated external flash units. > As I said, people are far too fast to accuse Pentax of deliberately > disabling bodies for the sole purpose of selling new lenses. They're all conspiracy theorists. ;-) Godfrey