Re: READ THIS ONE- Studio Photography

I tried this until I dropped the strobe and broke it. No reciprocity failure
at all. It's not exactly acurate, I don't think, to say that each "pop" is
necessarily a stop. Your extrapolation from metered readings involved
multiple "'pop units" going from one stop to the next in calculating the
pinhole exposure.
----- Original Message -----
From: John Yeo <jonnieo@thegrid.net>
To: <pinhole-discussion@pinhole.com>
Sent: Monday, November 20, 2000 7:21 PM
Subject: Re: [pinhole-discussion] READ THIS ONE- Studio Photography

> Why would reciprocity failure even be a problem? It occurs when there are
> very long exposure times. I beleive even the slowest flashes on the
market
> are much faster than 1/1000 of a sec, so even if you flashed 100 times, it
> would still be less than 1/10 of a sec, which is in the reciprocity range
of
> most films. Failure would not be a problem. If I am wrong, please
correct
> me, I've never tried it, this is just what 'popped' into my head.
>
> John
> ----- Original Message -----
> From: "Tom Ferguson" <tomf2468@pipeline.com>
> To: <pinhole-discussion@pinhole.com>
> Sent: Monday, November 20, 2000 5:14 PM
> Subject: Re: [pinhole-discussion] READ THIS ONE- Studio Photography
>
>
> > > From: Levi Brown <kerplop1@juno.com>
> > > Subject: [pinhole-discussion] READ THIS ONE- Studio Photography
> > >
> > > Andrew,
> > > I've been doing this for several years now... here is what you do.
> > > First determine the effective aperture of your camera. For my 4x5
mine
> > > is about F-256 and for my converted Hasselblad it is about F-140. Get
> > > yourself a flash meter and get your strobes close to your subject.
> > > Ideally if you can get your meter to read F-45 you are doing good.
This
> > > whole bit about doubling your number of flashes to add an extra stop
is
> > > nonsense. Everytime that you flash the strobes you add an extra stop
of
> > > light. Lets say that I set up my lights and get a meter reading of
> F-45.
> > > Lets count: F-45, F-60, F-90, F-128 That equals 4. So to get
> > > sufficient exposure you need to pop your flash 4 times. Just to be on
> > > the safe side do it 5 to add a little extra density and account for
> > > reciprocity. It really is that simple. With my Hasselblad my
exposure
> > > times are about 4 pops of the flash and with my 4x5 they run around 9.
> >
> > I'm sorry, but as someone who uses multiple flash pops for both pinhole
> and
> > lens work, this is simply WRONG. F45 to F128 needs AT LEAST 8 times as
> > many "pops". Lets count: F45 to F64 is one stop (X2), F64 to F90 is
> another
> > stop (2X2=4), F90 to F128 is another stop (4x2=8). I say "AT LEAST"
> because
> > reciprocity (on the other end of the spectrum from pinhole, flashes can
be
> > too short an exposure) can increase the number of "pops" needed.
> >
> > My best guess is that Levi is using Neg film, as surviving on it's
> > wonderfully forgiving exposure latitude :-)
> >
> > Try this with E-6 slide film or polaroid, and you'll see the truth.
> >
> > >
> > > Another trick, if you are shooting black and white, is to use Tmax 400
> > > speed film. Tmax has significantly less reciprocity failure than
other
> > > black and white films. I've noticed that I get better negative
density
> > > with Tmax than with any other black and white film.
> >
> > Agreed! It is a nice film isn't it. The 100 speed T-Max is even better
> for
> > reciprocity.
> >
> > >SNIP>
> >
> > --
> > Tom Ferguson
> > http://www.ferguson-photo-design.com
> >
> >
> > _______________________________________________
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> >
>
>
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Received on Tue Nov 21 06:58:16 2000