Hey all,
I worked doing forensic photography for 16 years; I had to shoot
in a lot of odd places with a lot of difficult subjects. A couple
of useful techniques for using flash:
If you have a flash unit that can be directed, aim it up or
sideways at a large white or off-white card ~9"x12". The card doesn't need to be perpendicular to the flash either, it works
well if the axis of the flash unit and the plane of the card are
close to the same angle (flash units tend to have a wide-angle of
light dispersion.) This produces a broad, soft (non-specular)
light that can gently illuminate many difficult subjects and
usually produce no 'hot spots', or small areas of over-exposure.
It especially helps with dark or shiny subjects. You can
experiment with different sizes of cards; can use shiny or 'flat'
(low albedo or reflectivity) material. It helps if your flash
unit is automatic -- senses proper exposure and shuts off the
light when it is reached. Using this, you may find that you can
set the unit for a slight under or over exposure based on
previous results, in order to get the best effect.
Another tip for success shooting through clear materials such as
glass or plexi: get the lens as close as possible to the surface
and try to have the predominant light source come from an angle
to the lens' axis -- from the top or the side.
HTH,
/ts
