Date: Mon, 3 Feb 2003 23:02:21 -0800
Reply-To: Bulletin Board for Bird Collections and Curators <AVECOL-L@LISTSERV.LSU.EDU>
Subject: Re: [AVECOL-L] photographing specimens
To: AVECOL-L@LISTSERV.LSU.EDU

Hi Jack and all-

Photographs for technical illustration-

Use a plain contrasting background so you don't lose the edges of important
subject matter. If shooting color and the final illustration will be
printed on color, that will be easy to do. Don't put a brown subject on
brown background, or if you do, make it a much darker or lighter brown,
etc. If shooting black-and-white, avoid tonal mergers by lighting the
background so the light parts of the object are against a somewhat darker
background, and the dark parts of the object are against a somewhat lighter
background. Or at least make sure that the tones are distinctly different
at the edges of important subject matter. When using b&w film, this is
harder than it sounds. You must never forget that the colors you are
looking at will be transformed into tones on a gray scale. A gray subject
on the same tone gray background will not be visible. This may sound silly
but look at a few black-and-white photos and you will easily find places
where the shapes of objects merge into the background. :-(

Use traditional "Rembrandt" type lighting. The main light source should
be in front of and to the side of the subject, and higher than the camera
lens. The exact position is important depending on what you want to
illustrate, Moving the light stand a few inches, raising the lamp a few
inches, or tilting/swiveling the lamp a few degrees can make a big
difference, so move things around but stay within the position rules
above, and take a lot of pictures. Don't use up-lighting, where the main
light comes from below, and stay away from back-lighting if it's for a
formal paper in a journal. (Back lighting is sometimes nice if it's for an
article in a magazine.) If you want to accentuate texture use a point
light source (spot light) and move the main light more toward the side of
the object rather than at side of the camera. If that's too harsh, broaden
the light source (flood light) or diffuse it with a white photo umbrella,
or reflector (white foam core from any art supply store).

After you set the main light set the fill light. Use a largish piece of
foam core to lighten the shadow side of the subject. If you can fit a full
a full sheet of foam core into the set up you can back up more and still
catch enough light for natural looking fill light.

The general rule of thumb lighting ratio for black and white is 3:1, I
sometimes shot as low as 2:1 for a technical illustration. 2:1 means there
is two times as much light falling on the light side of the subject as the
dark side. In technical illustration the priority is to present as much
information as you can, not to make a pretty picture. Imagine putting a
white cube in the setup with a edge toward the camera. If the face that is
lit by the main light reads f16 from the camera position, then for 2:1, the
face lit by the fill light should read f11 from the camera position, ...
remember each f stop is a factor of two, so f16 / f8 (two stops) would be a
4:1 lighting ratio. This is easier than is sounds. If you don't have a
spot meter, squint at your subject. Important detail in the dark side
(anything you want to see in the final picture) should still be
visible. Squinting is a very useful technique but it isn't exact, so shoot
varying lighting ratios, lighting angles, camera angles and bracket
exposures for each. The combinations may require a few dozen or more
shots. If you have to do a big series of similar subjects, shoot a test
roll of one subject first to nail down the lighting and exposure, then
shoot the rest.

Editors sometimes ask for "shadowless" photographs. I generally ignored
that instruction because the proper use of shadows is important. They
create form (three dimensionality), texture, and provide setting
(orientation). Use the fill light described above to lighten up shadows
cast by the object on itself as well as shadows on the background. Do it
right and it will rarely be rejected. Even if an editor has background
shadows retouched out, important tonal gradation of the subject will
remain.

Make the background look seamless.

It used to be that transparency film was almost required for publishing
color, I don't know what format publishers prefer these days, but whether
it will be black and white or color, use the slowest "regular" film you
can get. You don't need speed for table top photography, and sometimes a
photo will be published again in a larger form, so you'll you want the
highest quality possible, especially when shooting with the teensy 35mm
format. Oh, .. don't forget to use a tripod.

Here's another way to light a table top shoot. It limits the possibilities
but it's easier, and is much more forgiving. Find a window facing a sunlit
white wall ( white is important if it's a color shoot). Or hang a white
sheet over a window where the sun will fall on it. The larger the window
the more forgiving the light. Make a fist and hold it at arm's length in
front of you. Now turn around, move around, move side to side, in front of
the window until the light on your fist looks great. Now you know,
roughly, the camera/subject/light source angles to use. Put your
background and subject on a small table so you can easily move it if you
need to fine tune the set up. Have your assistant hold up a foam core
reflector somewhere to the side of the camera opposite the window Move
it/tilt it , up/down, in/out, sideways until the shadows are filled in a
natural looking way and shoot. You can ignore the no-up-light-rule with
the fill reflector and use it below the lens. Sometimes photographers will
end up poking the lens though a hole cut in the foam core. As above, shoot
a lot and use a tripod.

uhm, one last thing... If the nests or any subjects are small, try to use
a, hopefully longish, macro lens, and use as much available negative (film)
space as you can. Normal lenses work best at some considerable distance,
some many multiples of their focal length out to infinity. Macro lenses
are optimized to work best much closer, at fewer multiples of their focal
length. You want a longish macro so you can get a big image of a small
subject without having to get too close to it. Getting in too close starts
introducing perspective problems. Within reason, make use of as much film
area as you can, it can make a big difference in the quality of the image.

When shooting in close, you need to stop way down, especially with a
telephoto "micro" lens to get adequate depth of field. Hopefully f32 or
close to it will be available. Focus 1/3 of the way into the important
subject matter. Use long exposure times if you have to, and use your mirror
lock up feature with a pneumatic (not a cable) shutter release. I never
used a remote control release, I suppose one of those would work .....
maybe, if it was compatible with B shutter setting. Note: At over one
second exposures reciprocity failure starts to kick in, so bracket heavily
to the upside. If the meter says f32 at 1 second, also shoot 3 seconds, 6
seconds, and 12 seconds just in case. This little bit of esoterica saved
my butt on several deadline days.

Well three vodkas down the hatch now and I don't think I can reread this
thing again, hope it's readable.......

Have fun!

Sam Sumida
(net pole maker and former freelance photographer)
________________________________

At 05:42 PM 2/3/03 -0500, you wrote:
>Avecol readers...
>
>I need to photograph some bird nests and specimens for publication. Any
>suggestions as to backgrounds, lighting and film speed? I am using a Nikon
>35mm.
>
>Jack Eitniear
>CSTB Inc.
>Bull. Tex Ornithol. Soc.