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Re: filmscanners: Pixels per inch vs DPI
Oh yes, we always check ambient to flash ratios when we shoot. We
do tend to do a lot of mixing of lights in our celebrity portraiture, so
I'm well aware of the 5 stop increment.
On the other hand, we have been doing a lot of shooting (with studio
strobes) at 1/500th of a second recently, and maybe my memory has been
colored by the even greater loss of effective flash power with the extremely
fast shutter speeds of late. But again, don't go by what the manufacturers
spec, try it yourself and see.
We are photographing 'The Chemical Brothers' this weekend for a magazine
shoot, and if time permits, I will try to run a series of Polaroids, again,
to double check my understanding.
partner, SKID photography, NYC
Dave King wrote:
Sorry for the stupid question, but have you done this test in an
"effectively" dark room? Perhaps you're seeing ambient light
contribute to exposure? For ambient light not to have any effect
exposure it should be at least 5 stops below the working setting.
I thought the longest flash durations were in the neighborhood of
1/500th sec. I don't recall seeing exposure differences at shutter
speeds 1/250 or slower where ambient light isn't a factor.
----- Original Message -----
From: SKID Photography <email@example.com>
Sent: Wednesday, October 31, 2001 3:26 AM
Subject: Re: filmscanners: Pixels per inch vs DPI
> "B.Rumary" wrote:
> > Austin Franklin wrote:
> > > > As many people probably realize, in a typical rear
> > > > film cameras (as most 35mm SLRs are), any shutter speed beyond
> > > > maximum flash synch shutter speed exposes the film via a
> > > > opening between the shutter curtains.
> > >
> > > I know what you say CAN be certainly true for the highest speeds
> > > cameras, but I did not know it was specifically related to the
> > > speed...I believe it's more related to shutter design than
> > > to sync speed. Would you mind citing a source for that
> > >
> > > That is certainly not the case with vertical shutters, which
but one of
> > > my 35mm cameras have (Contaxes and Nikons), the exception being
my Leica M.
> > >
> > It _is_ related to the synch speed, because electronic flash is
> > it needs the entire image area exposed when the flash goes off.
> > speed is set above the synch speed, then the "moving slit" effect
> > only that portion of the film exposed by the "slit" at the moment
> > will get the benefits of the flash. The "flash-lighted" area will
> > correctly exposed, while the non-lit area will be heavily
> > Note this only applies to electronic flash guns, which give very
> > duration flashes - typically 1/30,000 sec. The old fashioned flash
> > "burn" much more slowly and give light for long enough for the
"slit" to do
> > it's full run across the film.
> I think you will find that very few, if any, flashes are of such
short duration. It has been my experience
> that the difference between, a 250th, 125th and 60th of a second
exposure and almost any brand electronic
> flash will yield very different film exposures, no matter what type
of shutter you are using.
> Harvey Ferdschneiderpartne
> partner, SKID photography, NYC