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From: smh@mhuxl.UUCP (henning)
Newsgroups: net.rec.photo
Subject: Re: Macro photography with flash
Message-ID: <423@mhuxl.UUCP>
Date: Sun, 5-Jan-86 13:22:35 EST
Article-I.D.: mhuxl.423
Posted: Sun Jan  5 13:22:35 1986
Date-Received: Mon, 6-Jan-86 03:30:14 EST
References: <154@hadron.UUCP>
Organization: AT&T Bell Laboratories, Murray Hill
Lines: 42

> I've been trying to do macro work using Canon equipment (A1) with a standard
> thyristor flash and have been achieving expected results - very under or
> over exposed pictures.

****                                                                 ****
From the keys of Steve Henning, AT&T Bell Labs, Reading, PA mhuxl!smh

I have been doing macro flash photography for years with standard Minolta
35mm cameras and standard flashes (Vivitar, Rollei, Braun, etc.).

1) You must make sure that the flash covers the field of view.  With a 
normal flash in a hot shoe and a 50mm macro lens, for close-ups the flash
goes over the top of your subject or just hits part of the subject. You can
tilt the light down with a swivel on the shoe or a hand held unit.  What I 
do is use a 100mm macro lens.  This places the working distance at a point 
which the flash can hit normally without a swivel mount or tilt down head.

2) You must reduce the power output of the flash so that the response time
of the unit is within the electronic capabilities of the flash.  Here
there are 2 techniques I have tried: 

First, I placed a piece of polarizing filter over the electric eye
on my automatic flash and then by trial and error found out what my
new auto f/stop was.  This has the added advantage of increasing your
f/stop and giving you a greater depth of field to work with.

Second, you can place a filter over the flash.  It must be a true neutral
density filter.  Again, a piece of polarizing filter works well.
I have used a white handkerchief to accomplish the same thing though.
Now your metering works normally and you have your normmal auto f/stops.
You must be carefull not to cover the electric eye with this filter.

3) You must allow for the normal increase in exposure required when
you do closeup photography if you do NOT use a TTL flash system.  This
is marked on most macro lenses so is an easy thing to do but requires
a conscious effort to remember for each shot.

4) The best flash macro photography system is one which uses a
leaf shutter rather than a focal plane shutter.  This permits you
to use every shutter speed on the camera rather than one that is
slower than a certain sync speed.  However, if you already have your
camera this is a bit extreme to change.