C crystals evaporated from aqueous solution. Copyright Thomas
L. Webster 2004
it all together...Once
I have the microscope set up and my crystals formed on microscope
slides I'm ready to make my images. As I stated earlier in the
section titled, "The microscope...", I cannot directly
view the effects of the crossed-polarizing filters through the
binocular head. The second polarizing filter, the "analyzer",
sits over the trinocular tube in the bellows. However, I have
become adept at predicting the effects of crossed-polarization
when viewing singly polarized substances. Those areas of a microscope
slide that will give "good color" will take on a 3-dimensional
appearance compared to the surrounding crystals. These areas may
also show a hint of coloring, too. When I observe areas, such
as these, in the binocular head I will then switch to observing
through the camera's viewfinder. More often than not I will be
able to see the effects of the crossed-polarizing filters in all
something looks particularly inviting I attempt to avoid high
powers. I generally use a 2.5x or 3.3x projection eyepiece combined
with a 4x flat-field achromatic objective lens for most of my
photographs. I am looking to add a 2.5x plan achromatic objective
lens for my crystal photography. The crystals that form aren't
as small as one would expect them to be. Many crystal formations
can be quite large, especially vitamin c that forms large, plate-like
crystals. Occasionally I will go to higher powers when I see some
interesting, fine detail but the images are dim and hard to focus.
Two polarizing filters can really "soak up" a lot of
light! I have a 30 watt illumination system that is normally fine
for exposures at higher powers. However, 30 watts is barely adequate
for powers over 100x. I am currently converting a 300 watt slide
projector as an illumination system. Stay tuned for that article!
the image on the camera's film plane can be quite a challenge.
I do have a special macrophotography and photomicrography focusing
screen installed in my camera but, again, the observed image can
be pretty dim and difficult to see. I also suffer from diabetes
that can sometimes cause daily shifts in my visual acuity. The
reticle in the right-angle viewfinder is focusable on a central
crosshair to allow for differences in eyesight correction. Most
of the time I find this woeflly inadequate and highly variable.
Instead of relying entirely on focusing through the viewfinder
I have devised a system that works pretty well. I have taken a
blank microscope slide and have carefully frosted a central area
with wet-and-dry aluminum oxide sandpaper. I lock open the shutter,
open the camera back, and place the frosted central area of the
microscope slide over the film plane with the frosted side down.
I then use a focusing loupe to carefully focus the crystal image
on the film plane. Afterwards, I adjust the reticle focuser on
the right-angle finder such that I see a sharp overall image through
the camera's viewfinder.
make all of my exposures on either Kodak or Fuji ISO 100 color
negative print films. First of all, I am a very "financially
challenged" individual with a teenage daughter to raise!
Color negative films are much more affordable than color transparency
films. I can buy four, 24-exposure rolls of Fuji Super HQ ISO
100 color print film (my favorite) at WalMart for about $5.00.
Processing only costs about $2.00 per roll. Second, since I scan
all of my images it doesn't really matter if I am scanning color
negatives or color transparencies. Third, color negative films
have a higher dynamic range than color transparency films. The
new consumer color negative emulsions are getting finer grained
and more saturated every year. Just what we need for photomicrography!
Depending on the magnification exposures will range anywhere from
1/8 second to 7 seconds. I use an 80B or 80C filter to compensate
for the warm tungsten illumination system. Exposures with thin
crystal preparations can be tricky. Because of the clarity of
the crystal preparations and the fact that transmitted light is
used I invariably have to use an EI of 200 to 260 to achieve properly
exposed negatives. (End...)