What is
"the" perfect exposure? The
ultimate answer is more a matter of personal taste than
expertise.
My opinion is that are really two criteria for perfect exposure. First is how and what you want to
communicate in your photograph and second is what reproduces detail in
either the print or printed page (to make perfect or more nearly
perfect...).
Our Perfect Exposure
We tend to lose sight of what photography is really about -
communicating. We don't have brush strokes available to us to emphasize
the subject. We can't give rise with a crescendo to bring drama to our
subject. We can't even add the perfect adjective to better describe the
subject. What we have to communicate with is light and how we expose for
it.
Light is what gives life to our photograph, and exposing for
it is what defines our own personal perfect exposure. For example, we
can tell from a photograph whether it was taken on a sunny day or
overcast day. We weren't present at the time of the exposure, but the
quality of light and how it was exposed clues us in as to the time it
was taken.
Was the photographer trying to communicate
or were they just following "the rules?" A sunny afternoon can
be underexposed to darken the scene and an overcast day overexposed to
brighten the scene. All of a sudden we have taken control of exposure
making. We've now changed the scene to fit our desire, we're now
communicating by finding our perfect exposure.
There are a number of common situations that mess up the
photographer's mind when it pertains to exposure. The most common is
snow. Oh my goodness, the number of letters I've received on how to
expose for snow. The rule so often quoted is overexpose by at least one
full stop. I hate rules! "You" have to decide what's the
subject and then expose for it. If the subject is the snow and you want
to see detail in its crystals, then overexposure is called for. But if
the snow is a mere element in the photograph, overexposure is probably
not going to give you the perfect exposure for what you're
communicating.
Now this holds true for other light subjects as well as dark
subjects. The white bird on blue water has to be the ultimate nightmare
for the quest of the perfect exposure. But with my formula, it's quite
simple. If the white bird is the subject, then overexposure is right. If
the white bird on the blue water is just an element, then overexposure
is not needed. And when do you know which is correct? What is it you
want to communicate?
You, the photographer, the communicator,
must make the decision on what it is you want to say. The disappointment
many feel from their photographs when it comes to exposure is not from
detail missing in the highlights or the shadows (to be discussed in a
moment), but because it does not communicate what we wanted about the
scene.
The Focal Encyclopedia of Photography,
third edition says this about the perfect exposure, "The correct
exposure for a photograph can be defined as an exposure that produces an
image with the tonalities and colors the photographer desires,...".
In this pursuit of communicating, technical expertise in exposure is
important. Don't get me wrong, you must know what you are exposing for
to communicate. But it is not the dominating factor, at least in my way
of thinking, of the perfect exposure "....to leave nothing
wanting."
Image Viewing
This is a digression from the topic of expsoure but it warrants mentioning. If you do a lot of bracketing you will wind up with a lot of images on your computer. If you are like many photographers the DELETE button is not one of the heaviest used buttons. As a result, you will use a lot of disk space saving images you do not need. The link below will take you to Google's Picasa. It is an excellent image catalogin and viewing program. Many photgraphers find images they didn't know still existed when they run this program. It will scan the computer and index all images except those in folders you excluded. Please check it out.
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The Technically Perfect Exposure
The math of the technically perfect exposure really isn't
that hard to spell out. Positive film (sorry, I can only speak for the
film type I know, others differ), has generally an exposure range of 2
1/2 to 3 stops. This means that any highlights or shadows in the scene
within this exposure range contains detail. But this very phrase might
create more confusion than it clears up.
A scene has a range of exposures for each and every element
contained in it. The proper exposure for an element in a scene is when
detail can be seen in that element, detail such as leaves, ruffles in a
cloud. etc.. For example photographing a sunny scene (shutter speed for
this example not relevant though would be constant for all), to expose
for the highlights such as a cloud, an f/stop of f/16 might be required.
Proper exposure for the shadows, the leaves at the bottom of a bush,
might require an f/stop of f/5.6. If the highlights of the scene can be
properly exposed at f/16 and the shadows at f/5.6, then they fall within
the 2 1/2 stop range and detail is captured throughout the scene. In our
photography we find this the exception and not the rule. (Obtaining the
exposure for this scene can be derived in a number of ways and in itself
is another article/book.)
Generally, the exposure range of our scene is greater than
the range of the film. Depending where we place our exposure, either
highlight or shadow detail is lost because it falls outside this range.
This means that either highlights are burnt up, washed, or the shadows
are blocked up, black, neither holding any detail. When this occurs,
these photographs are referred to as "contrasty."
In the quest for the perfect exposure, solving the technical
side is easy to answer. Typically, we expose for the highlights and pump
light into the shadows to bring them up within the magical 2 1/2 to 3
stop range. We have such tools as fill flash and reflectors to help fill
in shadows. Their proper application when not detectable, lowers the
exposure range of the scene so detail can be captured, while effectively
communicating. (If you look closely at my photographs, you'll notice
that I typically let shadows go dark in scenics while with wildlife,
there is shadow detail. That's just my personal preference for the
perfect exposure.)
Now means of metering to determine the proper exposure for
various elements or scenes can vary. Preferences for exposing for the
highlights or shadows can likewise vary, but the fact that we have this
2 1/2 to 3 stop range remains. The technical question of the perfect
exposure lies within and outside this range. It is a question you can
answer by simply applying the many tools available to us effecting
exposure.
Whenever you are performing tests you should also be talking
to your lab. A professional
relationship with your lab is a critical component of any testing.
Just to provide you food for thought, when you have a
photograph where the highlights and shadows are within this range, you
have the perfect exposure for prints or the printed page. I still
contend this might not be the perfect exposure for the scene or what you
want to communicate, but it will render the perfect print. This includes
providing the ultimate in sharpness. There's no doubt that sharpness of
an image is at its greatest when the exposure is within this range
"....according to a given standard... "
Obtaining Your Perfect Exposure
But you're saying, "Moose, how do I know what I want or
what happens when I apply a filter or underexpose?" Experience is
still the best teacher because we all see differently and communicate
differently, but I can provide you some insights as to what I do.
An example is shooting on overcast days. This to me is a
magical time for photography. The exposure range is generally within the
2 1/2 to 3 stops without having to mess with flash or filters. Now if
the scene has a definite mood to it, such as a stormy coastline or trees
in fog, I expose as the meter advises. This generally underexposes the
scene creating a darkened image. This creates a dark mood to the scene,
communicating the mood I felt while making the exposure.
But I have found I can take this same overcast light and
change everything by simply overexposing. Photographing in forests, or
other normally contrasty places, are best when it's overcast. But by
exposing for the mood, the scene becomes very dark and gloomy. This is
not what I want to communicate in many instances. So simply by
overexposing by 1/3 to 1 stop, I can change the scene dramatically. How
dramatic? You won't even know by looking at the scene for example, that
it was raining because it looks so bright. The thing that gives the
technique away is that the highlights and shadows still hold detail.
Changing the exposure range to communicate what you want
affects other elements in the photographic equation. Beware that for
every action, there will be an opposite and equal reaction. By changing
the exposure to obtain your perfect exposure, such things as contrast
and color changes. Underexposing a scene generally saturates colors more
where overexposure washes them out. The rich greens of a forest like the
underexposure where the pastels of a field of flowers like the
overexposure. And of course, the exact opposite might be what you like
to capture.
So where have I led you in this discussion of the perfect
exposure? Hopefully right back to where I wanted, to you. I want you to
understand that the perfect exposure is what you like. You are the final
judge as to what is perfect or not. You and only you know if what you
saw in the scene is what you captured and communicated successfully. And
you will know this not only from your own reaction to your image, but by
the reactions of others. Anyone can master the technical side of
exposure. Heck, most modern cameras can obtain the correct exposure for
90% of the scenes we encounter. But the real pro must reach down deep
inside to master one's own perfect exposure. You won't find the answer
to the perfect exposure in my words, but only in your photographs! |
