Dear Shell Photographers:

I have read the last series on photography with interest, since I am the
Photographic editor for American Conchologist.  Producing good
photographs of shells depends upon many factors, but primarily upon what
type of pictures you want to produce.  Price tag is also of importance
(35mm as well as digital).

Lenses:  Taking pictures of shells falls into the realm of macro- and
micro-photography.  This means pushing lenses to the limits of their
design.  Generally speaking you should use lenses that are designated as
"macro".  This designation means that they are highly corrected lenses
which produce excellent quality images with the use of extension tubes.
Using a general lens with extension tube will produce an image which is
slightly blurred, with much less resolution.  The drawback of most
digital cameras is their lens (usually low quality).  Excellent lenses
are found only on the higher models of Nikon, Olympus, and Sony digital
cameras.  These lenses are up to the demands of macro- and
micro-photography.

Depth of Field:  Depth of field is also associated with lenses.  It
refers to the depth or thickness of an object which is in focus to our
eyes.  To increase depth of field, or the amount of the image apparrently
in focus, increase the F-stop.  However, as magnification increases your
depth of field decreases.  Eventually, all of the shell will not be in
focus.  Then multiple pictures are necessary (covered latter.

Lighting:  Adequate lighting is necessary for both resolution and color
rendition.  Low levels of light produce grainy images of incorrect
color rendition.  The general rule is the brighter the better for both
resolution and color.  This becomes a necessity in macro- and micro-
photography when using higher F-stpos to increase your depth of field.
As the F-stop increases the level of light delivered to you film or CCD
decreases.

Color balance or color rentition is also affected by lighting.  Film
and CCD react to different sources of light producung different color
renditions.  Tungste/halogen are richer in reds.  Fluorescent is richer
in blues.  Flash produces a narrow window of both reds and blues.  With
a digital camera you are stuck with one CCD and its reaction to light
of different wavelengths.  However, with filn you can use a film
produced for different sources of light (e.g tunsten).  To achieve
proper lighting you may end up using tungsten, flourescent and flash
all at the same time (I do).

Compositing:  Tis term refers to assembling parts of different images
into one image.  In extreme macro-photography and micro-photography
eventually magnification become so high that not all of the image is in
focus.  Take multiple images so that all of the shell is in focus in at
least one of the images.  To accomplish seamless compositing you have
to convert the image into digital format using either a flat bed
scanner or a slide scanner.  Scan each image.  Using a graphic imaging
program, such as Adobe Photoshop, you select the parts of the image
that are in focus and reassemble them into one image.  Now the entire
shell is in focus.

Cost:  You cannot produce superb images of shells with inexpensive
equipment.  Good quality macro lenses run from $200 - $600.  Generally
speaking the higher the price tag, the greater the lens correction to
produce sharp images.  Extension tubes are less expensive $50-$175.
Digital cameras capable of producing high resolution images are now
available from $800.  No comment is being made here about "hidden costs".

These comments are the tip of the iceberg and not meant to be exhaustive.

Is anyone interested in a photographic clinic at the COA meeting in
Houston??

Best, Ross