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
