Mark,
You can quote the manual all you want. The manual is not correct
in that it doesn't specify the "A" series manual focus lenses'
operation properly.
I tested flash behavior using a Pentax-A 50mm f/1.7 lens on my
DS body and what I reported is how it behaves. The flash does
P-TTL in all exposure modes with these lenses: Av mode locks the
shutter speed at 1/180, P, Tv and M modes operate as you would
expect. It also supports P-TTL using lenses without electrical
aperture coupling in Av mode at full aperture (or manually
stopped down, in the case of screw mount/mirror lenses and the
like), I believe, although I did not test this explicitly.
The DS' built-in flash only reverts to full output, non-metered
mode when a lens that has no aperture information electical
couplings (M and K bayonet; A lenses with the lens taken off the
'A' setting) is fitted and Manual exposure mode is selected.
Godfrey
--- Mark Erickson <[EMAIL PROTECTED]> wrote:
>
> Godfrey DiGiorgi wrote:
> > Mark Erickson wrote:
> > > I took a look at the *ist-Ds manual, and it appears that
> if an
> > > older lens (i.e., not an FA, FAJ, D FA or DA) is mounted
> and
> > > the built-in flash is used, the shutter speed is fixed at
> 1/180
> > > and the flash always fires at full power (see page 147 of
> the
> > > manual). Yikes! Seems like a little bit of a limitation,
> > > doesn't it?
> >
> > Not quite correct. An A manual focus lens works the same as
> an
> > FA/DA/D-FA/FA-J lens in P, Tv and M modes; in Av mode,
> shutter
> > speed is fixed at 1/180 second.
>
> Let me quote from page 147 of the manual:
>
> Using the Flash in Tv (Shutter Priority) Mode
> ...
> The shutter speed is fixed at 1/180 sec. when lens other
> than
> DA, D FA, FA J, FA, or F is used. (The built-in flash always
> discharges fully.)
>
> ...
>
> Using the Flash in Av (Aperture Priority) Mode
> ...
> The shutter speed is fixed at 1/180 sec. when lens other
> than
> DA, D FA, FA J, FA, or F is used. (The built-in flash always
> discharges fully.)
>
> My reading of this is that the *ist-Ds does not in fact treat
> SMC-A lenses the same as DA, D FA, FA J, FA, or F lenses in
> Av or Tv mode. Also, the fact that the built-in flash always
> discharges fully seems to be a little limiting, as well.
>
> --Mark
>
>
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