Sponsored by the
Museum of Natural
Science, Louisiana State University
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, then
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, and 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.