Black and White Photography

Working in manual exposure mode teaches you a lot about how exposure
works, as you must set the f-stop and shutter speed yourself, while providing
you with a lot of control over exposure. In particular, manual exposure mode
works well for making subtle adjustments in individual exposures for those
times when you want just a little more or a little less light than the meter suggests.
Adjust the f-stop and shutter speed until you reach the recommended exposure,
and then tweak one setting slightly to allow a little more or less light in.
Program autoexposure mode (P). In program autoexposure mode, usually indicated
by a “P,” the camera automatically sets the f-stop and shutter speed for
you. You simply point the camera, compose your picture, focus (or allow the
lens to focus automatically), and press the shutter button. The chosen f-stop
and shutter speed are displayed as you look through the viewfinder and/or look
at the camera’s external LCD display. In theory, you will get the same exposure
recommendation that you would get in manual mode, except that in program
mode the camera sets them for you, while in manual mode you set them yourself
(with the meter’s help).
The most obvious advantage of program mode is its simplicity. All you have
to do is set “P” on the camera and take your picture. You are yielding control
over the exposure settings to the camera, but this mode works very well for
most quick, spontaneous picture taking and for subjects with average lighting
and tonal ranges—a good balance of darks, middle tones, and lights.
Note that in program mode, you can gain an extra measure of exposure
control by using program shift, an option that allows you to choose a specific
f-stop or shutter speed, usually by rotating a dial. For example, suppose the
meter sets exposure automatically at f/8 at 1/250, but you want more depth of
field (for a landscape subject) or a faster shutter speed (to stop the action of a
dancer in motion). Simply change the lens aperture opening to f/11 for greater
depth of field, and program shift will automatically change the shutter speed to
1/125 to compensate; or change the shutter speed to 1/1000 to stop motion,
and program shift will automatically reset the lens aperture to f/4. You must
activate program shift with each exposure; after you take a picture, the camera
will revert to the program’s set f-stop/shutter speed settings.
Aperture-priority autoexposure mode (A or Av). With aperture-priority autoexposure
mode, indicated by “A” or ”Av” on your camera, you choose the
f-stop you want, and the camera automatically sets the corresponding shutter
speed needed for good exposure. This mode gives you the advantages of autoexposure—
simple and quick operation—but with more immediate control
over depth of field. For example, you can set the lens aperture at f/16, which
will provide a lot of depth of field when photographing a landscape subject, or at f/2 for reduced depth of field when making a portrait, and the camera will
set the shutter speed for you.
Aperture priority also is very useful when you are photographing in low
light. Knowing you will need a lot of light for adequate exposure, you can set
the camera to “A” or “Av” and set the lens to its largest opening, perhaps to
f/2.8 (depending on the maximum aperture of your lens), and let the camera
adjust the shutter speed as needed.
Be careful you don’t set your aperture too small or too large for the lighting
situation. If you close down to a small lens opening, for example, to f/16 in dim
light, your meter may have to set a very slow shutter speed, perhaps 1/2, which
could result in a blurred image. Or if you open up your lens aperture in bright
light, for example, to f/4, your meter may not be able to set a fast enough shutter
speed. Many cameras will beep or display a warning in the viewfinder if the
needed shutter speed is faster than the camera can set. Or, they may not allow
you to take the photograph at all. Note that most cameras don’t alert you when
you’ve set a shutter speed too slow to hold the camera steady.
Shutter-priority autoexposure mode (S or Tv). With shutter-priority autoexposure,
indicated by “S” or “Tv” on your camera, you choose the shutter speed
you want for your subject, and the camera automatically sets the corresponding
f-stop needed for good exposure. Like aperture-priority, this mode offers
the simplicity and quickness of autoexposure, but with more immediate control
over subject or camera movement.
Perhaps the best use of shutter priority is when a fast shutter speed is required
to stop action. Knowing you will need to freeze the movement of a
runner at a track meet, set the shutter speed to 1/1000 or faster—letting the
camera automatically adjust the f-stop as needed. Alternatively you can deliberately
choose to make the runner a blur by setting 1/4 or some other slow
shutter speed.
However, be careful you don’t set your shutter speed too fast or too slow
for the lighting situation. In low light, your lens aperture may not open wide
enough to accommodate a fast shutter speed, for example 1/1000, and in bright
light it may not close down small enough to accommodate a very slow speed,
such as 1/4. As with aperture priority, either problem may set off a beep or a
display warning, while some cameras won’t even allow you to take the picture
unless you’ve set a workable shutter speed.
Subject-program autoexposure mode. Some cameras offer a subject-program
autoexposure mode designed to optimize settings for specific subjects. You
choose the subject by setting icons on a dial on the camera body or on its LCD
display (and sometimes in the viewfinder). Then the camera determines both  the f-stop and shutter speed automatically, according to what it presumes is
best for the chosen subject.
Typical modes include portrait mode (usually indicated by an icon of a head
and shoulders), for which the camera will choose a large lens aperture to
produce less depth of field and soften distracting backgrounds; landscape mode
(usually a mountain icon), for which the camera will choose a small lens aperture
for greater depth of field; sports or action mode (usually a running figure),
for which the camera will choose a fast shutter speed to stop motion; and
macro mode (often a flower icon) for faster, more accurate focus when photographing
close up.
You can accomplish the same results using any of the other available exposure
modes. However, some photographers prefer to allow the camera to make
these kinds of subject-based decisions for them.
There are several strategies available for calculating exposure, whether you are
using an in-camera meter or a handheld model. When used correctly, each
strategy will lead to more or less the same f-stop and shutter speed recommendation.
However, you may prefer one method or another or find some approaches
are more suited to certain types of equipment or lighting situations.
Take an overall meter reading. The most common exposure strategy is just to
take an overall meter reading. Simply point your camera (or your handheld
meter) at an entire scene and use the indicated f-stop and shutter speed settings.
Much of the time, this simple technique works just fine. But before you accept
that reading, examine your subject carefully. Visualize the scene as it might
look in black-and-white, then decide whether the dark, middle, and light tones
roughly average out. If they do, you can probably use the indicated f-stop and
shutter speed to achieve correct exposure. If they don’t, you will have to make
an adjustment.
If the scene has mostly light areas, add a little more light than the meter
suggests, either by opening up the lens aperture or using a slower shutter speed.
Adding light with a light subject may seem counterintuitive. But remember that
the meter always provides a reading to produce middle-gray—and here, you
want tones that are lighter than that. Exposing the film for more time will make
bright areas denser (darker) than gray on the negative and lighter (whiter) in
the print.
With light areas usually an adjustment of one-stop increase (or even less) is
all you will need. So if the meter suggests f/8 at 1/500, use /f5.6 at 1/500 or f/8
at 1/250 or some other equivalent instead. If the scene contains predominantly
white tones—for example, when it is mostly bright sky, snow, or sand—you