Re: 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