At 3:12 -0500 21/1/03, Magdalena Cano Plewinska wrote:
>I did think about side lighting. Trouble is, that's kind of hard to
>set up in clinic, where you have only a couple of minutes to take the
>picture. I guess, as a variation on the theme I should experiment with
>positioning the hand/foot differently with respect to the overhead
>lights. A pen light or otoscope would be my only other option. Worth a
>try, too.
You said you have a Sony 707 digital camera and the discussion below relies
on the fact that it has an external flash connection and tripod screw mount.
Here's a very detailed review and explanation of this camera, with much
technical information: Sony DSC-F707 Review, Phil Askey, August 2001.
http://www.dpreview.com/reviews/sonydscf707/
Unfortunately, although small and light, the 707 has a weird physical
design that makes medical and technical photography more difficult. It does
have just about the closest-focusing macro capability of any digital camera
-- almost too close!
The lighting technique I've described can be used even if you don't use the
tripod mount for a flash bracket, but do use the Sony dedicated external
flash. Just hand-hold the flash. The techniques are also valid if you have
to work with natural light.
By the way, your flash-on-camera pictures are overexposed because the flash
exposure calculation only works down to 0.5 meter; closer and it's too
bright. The flash is so close to the lens axis that for all practical
purposes, it's almost like a ring-light (good suggestion by another reader,
but impractical here). Another reader gave the easiest way to dim it:
Kleenex.
But No to the penlight or otoscope; too little intensity and too narrow a
beam and hard to position/direct for side light.
And no to the fluorescent lights.
If nothing else, turn the room lights off, close the blinds to exclude
daylight, and use a desk lamp or other examining lamp angled for
cross-lighting.
Ideally, you want something that is practically automatic, a one-piece unit
that only requires turning on and placing the hand in front of.
Fortunately the 707 has a good tripod mount, directly under the lens barrel.
It also has a separate dedicated external flash unit, the HVL-F1000, which
is available from a number of sources. Here's one:
http://www.pcconnection.com/scripts/productdetail.asp?product_id=209664
Here's a link with a picture of it attached to a Sony 505 camera (same body
as 707) on a bracket that screws into the tripod socket under the lens.
http://www.dpreview.com/news/0004/00042601sonyvs.asp
You would angle the bracket so it sticks out to the side and in front of
the lens, and angle the flash back towards the subject area in front of the
lens. Unfortunately, the bracket that comes with the flash is pretty short
and does not have a swivel to turn the flash back towards the subject. You
can get a swivel and/or a replacement bracket from B&H Photo, a
professional camera store in New York City that does mail order -- it's
terrific.
Here's a suitable swivel that should work with any bracket that comes with
the flash. Strobofame Shoe-Mount Swivel Ballhead (With Flash Shoe) B&H
Price: $19.95
http://www.bhphotovideo.com/bh2.sph/FrameWork.class?FNC=ProductActivator__Aproductlist_html___52637___STBHSM___REG___CatID=0___SID=F317B95D0B0
And here's a flat bracket that you can use if the flash doesn't come with one:
http://www.bhphotovideo.com/bh2.sph/FrameWork.class?FNC=ProductActivator__Aproductlist_html___93392___GBBFS___REG___CatID=0___SID=F317B95D0B0
General Brand Straight Flash Bracket B&H Price: $8.95
(If the above long URLs don't work automatically, copy and paste them into
your browser address window, making sure not to leave and spaces or leave
out any letters. If you can't make them work any way, go to the main B&H
page, http://www.byphotovideo.com, and enter the descriptions in their
search field.)
If you scroll through the flash brackets category of accessories, you will
find there are also many advanced flash brackets that will make you look
like something from Mars, but will let you put the flash anywhere you want
it:
This Sony flash is the only one that will work externally with this Sony
camera. It's a very powerful unit, made for shooting in low light and at
great distances. So it will need heavy diffusion to cut its output to an
acceptable level, and you'll need to do tests. However, this diffusion will
also make the light softer, if still highly directional; this means more
color saturation especially in the shadows, while retaining the modelling
of three dimensional features.
Using a separate flash, held on a bracket from the side of the camera, you
will get the side light (contrary to most normally good suggestions here, I
don't think you want soft frontal light) and have a fixed unit that
requires no setup, no adjustment, no fussing. With the digital camera's
flash mode, you have no worries about other light or color balance, and you
have an LCD screen to use for focus and framing. And you don't have to
worry about the background grey card, because if you hold the subject's
hand several feet above the floor or away from the wall, the flash won't
illuminate the background much, and you'll get gray to black backgrounds
anyway.
This kind of lighting technique is important for clinical reasons: accurate
color rendering of lesions, subcutaneous neoplasms and vascular structures,
and, as you've already mentioned, skin color itself. Not to mention the
sometimes subtle three-dimensional changes to the epidermis' contours and
lines, that only show with hard, angular light that casts shadows.
Now that's a pretty exhaustive discussion of the problem and solutions, and
I hope it hasn't exhausted you, Magda, or anyone else interested in such
technical work. It's probably no more involved than any other kind of
nature or close-up photography, and certainly no worse than learning a new
medical/surgical procedure! (Remember practicing your stitching, Magda?)
Any other suggestions or corrections are welcome from all, and any
questions, too.
Hope this helps, and keep us posted. Also, show some pictures -- medical or
general.
Cheers,
Michael
--
Cheers from Godzone,
Michael Kopp
Wellington, New Zealand
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