Dear Ray,
Not TTL OTF flash, but manual or auto metering.& flash unit
controlled auto flash.
Tom
On 8 Jan 2001, at 2:22, sayeth Ray Moth <ray_moth@xxxxxxxxx>
> Hi Tom,
>
> Yes you are right, I think - at least what you say makes sense to me
> but I've never tried it. I've always thought, however, that you'd have
> to use auto-flash not TTL flash to get decent fill-in. I wasn't really
> thinking about that when I wrote my response to Dirk's question, I was
> just trying to clear up what appeared to be a misunderstanding on
> film-speed in relation to auto-flash.
>
> Also, as you say, most flashes give you several f/stop settings for a
> given ISO. That was what I meant when I said that the availability of
> three 'dosage' levels is provided so that there is some flexibility in
> the aperture settings that can be used.
>
> Regards,
>
> Ray
>
> --- "Tom A. Trottier" <TomATrottier@xxxxxxxx> wrote:
> > Dear Ray,
> >
> > In other words, set the flash computer for your film ISO, note the
> > f/stop suggested, and set your camera to one stop narrower for 1/2
> > fill. e.g., flash says f/8. Set camera at f/11 for 2:1 ambient:fill,
> > f/16 for 4:1, etc. Set (or watch on auto) shutter speed to give
> > proper ambient exposure, but equal to or longer than 1/60th for
> > proper sync.
> >
> > Most flashes give you several f/stop settings for a given ISO.
> >
> > Tom
> >
> > On 7 Jan 2001, at 18:33, sayeth Ray Moth <olympus@xxxxxxxxxxxxxxx>
> >
> > > Dirk Wright wrote:
> > > I'm thinking hard about this before a full cup of coffee, so maybe
> > this
> > > is wrong, but if the film speed setting *does not* effect flash
> > output,
> > > then how does the flash know what speed film is being used in the
> > > camera? For the flash to determine proper exposure, it needs: film
> > > speed and reflected light from the thyristor, correct?
> > >
> > =====================================================================
> > > As far as I know, a flashgun has, typically, three selectable
> > levels of
> > > output ('doses') in auto mode. The intensity of each of these
> > 'dosage'
> > > levels is controlled by the flashgun and depends on the light
> > reflected
> > > back from the subject, which is measured by the flashgun's sensor.
> > The
> > > illumination of the subject is controlled to allow for variations
> > in
> > > flash distance and subject reflectivity.
> > >
> > > The illumination of the subject does *not* change with the speed of
> > > film being used; what does change, however, is the lens aperture
> > that
> > > would be appropriate for each flash 'dosage' level, to achieve
> > correct
> > > exposure. This obviously depends on the film speed. E.g. a
> > particular
> > > auto setting on the flashgun ('dosage' level) might require the
> > lens to
> > > be set at f/4 for ISO 100; for faster films, a smaller aperture
> > would
> > > be required: f/5.6 for ISO 200, f/8 for ISO 400, and so on. The
> > > availability of three 'dosage' levels is provided so that there is
> > some
> > > flexibility in the aperture settings that can be used.
> > >
> > > There is usually a built-in sliding scale on the back of the
> > flashgun
> > > that can be set to the required film speed and shows the aperture
> > > should be set for each of the 'dosage' levels. The setting of this
> > > scale does nothing to the flashgun, it is merely a user guide.
> > >
> > > Regards,
> > >
> > > =====
> > > Ray
> > >
> > > "The trouble with resisting temptation is
> > > you never know when you'll get another chance!"
> > >
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> >
> >
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> > Tom Trottier <TomATrottier@ home.com> ICQ: 57647974
> > Abacurial Information Technology Consulting
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-----------------------------------(no spam please)
Tom Trottier <TomATrottier@ home.com> ICQ: 57647974
Abacurial Information Technology Consulting
400 Slater St. Suite 415, Ottawa ON Canada K1R 7S7
__o +1 613 291-1168 fax:594-5412 (877)247-8796
_ \ < Vote for your favourite Olympus camera at
(+)/'(+) http://www.freevote.com/booth/fav_camera
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