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Part 1 of 3, On to 2, Over
to 3
| Photography is all about controlling light. All the gear,
film, processing, and reproduction equipment used in photography is for
the purpose of manipulating light.
There are only four elements that determine a photograph. Let's go over
each of these and give some nuts and bolts examples of common errors and
solutions for each of their consequences.
These aspects are all interrelated as you will know. |
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| This is the basic formula for how the elements of
photography are related... very fundamentally, Aperture value (f-stop) or
the opening/diameter of your lens diaphragm plus the amount of time the
film plane is exposed is equal to a measure of entering light
(incandescent and reflected) plus the chosen films capacity (ISO) for
recording light energy. You can see that by dividing one value you can
isolate it and express its relationship to the other three... Practical
applications here are such things as doubling the aperture value allows
for halving the exposure time... to result in the same amount of light
reaching the film plane... |
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| First off, we should define a few terms, and narrow this
necessarily huge subject area down to something manageable within the time
frame, interest levels of all here.
Yes, there are electronic image making devices (digital), and yes, they
can make useful images for hobby and business use. Some of their use is
identical, other more peculiar to this new medium. For the most part we
will focus on analog (film) photography, in particular the making of
transparencies (slides) as this is the current industry standard. <Give
pers... ex.s> |
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| Luminance is a measure of all the incidental light emanating
from an object... and is measured in a few ways (lux = 1 meter-candle, =
about 0.93 lumens...). It is composed of incandescence (black body
radiation), luminescense/fluorescence/phosphorescence as themselves and as
reflected light energy. Basically, we register all of this as
"light". |
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| As we've agreed, photography is all about controlling light.
As such, it is paramount to either understand the light available to you,
or to augment, replace the light with quantities and qualities you can
provide. There are many dangers here. The human eye, coupled with your
brain is an able deceiver... the best lenses can discern about nine
f-stops, you can make out thirty some...
Light meters are invaluable tools. From simple "in camera"
types to flash/reflected ones of spot to broader area application... they
can/will save you time, money... |
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| There are more difficulties to making a correct exposure
than knowing and controlling the four aspects of image making... Very
commonly, simple mechanical errors in placement of flash, lighting units
will spoil aquarium photographs by "flare", reflection outside
and inside a tank. Best to have the outside dimmed, and carefully place
ones light sources at angles, away from the camera. <Examples: Grier/Tepoot,
myself/others, polarized filters...> |
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| Side lighting can yield desired, dramatic effects. A
seasoned photographer will take many shots moving the lighting source/s
about. |
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| Even if your intended subject appears well lit to your
"naked" eye, adding some "fill light" can/does serve
to "fill-in", accentuate details that might/do otherwise go
unexposed on films. In this case, the Lysmata shrimp was side lighted from
the upper right relative to the film subject and camera. |
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| Shadows can and do lend definition and depth perception to
images, but they can also easily detract from the subject matter or
otherwise clutter your intended effect. As in so many other aspects of
reality, it's not just "what you have in", but "what you
exclude" that makes such a difference. |
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| Why I'm like Bruce Lee: I can throw, from so much practice,
two by two slides where I want and make them stick into the wall... Very
common to be tossing a bunch of your efforts in the trash as a consequence
of "no light"... these are the principal causes... and
solutions.
<Ex.s Show my Nikon set up> |
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| How wide the lens is open, what materials it's made of, and
how the elements are arranged determine "how fast" or slow your
lens can gather light and focus it onto the film plane. In life there are
all sorts of trade-offs and with lenses, the size of the opening (f-stop)
is directly related to how deep the depth of field you have (doubling
f-stop doubles depth of field) and the amount of light you need to make a
"correct" exposure (keeping time of exposure and film ISO
constant)... |
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You want to set your f-stop high for the maximum depth of field... but
on the other hand, you need to set it low to allow in the greatest amount
of light... or you could increase the length of time your shutter is
open... but then the image might be blurry... or you can switch to a
faster film (higher ISO), but then the image may be too grainy or not as
color rich... Maybe a trade off, adjustment between these four variables,
hmm?
Images showing about a full stop over and under exposed, and one
"about right". |
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| There are three practical things a photographer can do to
adjust for depth of field: In actual practice, plan on doing all
three. |
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Click here for Part 2 of 3 of Aquarium Photography
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