2

CHAPTER
NIGHT AND LOW-LIGHT PHOTOGRAPHY / All About Light and Exposure

are letting in exactly twice as much light. The

following list of apertures are all exactly 1 full

stop of light apart from each other:

f/1.4, f/2.0, f/2.8, f/4.0, f/5.6, f/8.0, f/11, f/16, f/22,

f/32, f/45, f/64

Many of the cameras available today allow you to

adjust the aperture in 1/3 or 1/2 stops. This gives

you much more control over how much light is

allowed through the lens.

The f-stops available when using 1/3 stops are as

follows:

f/1.4, f/1.6, f/1.8, f/2.0, f/2.2, f/2.5, f/2.8, f/3.2,

f/3.5, f/4.0, f/4.5, f/5.0, f/5.6, f/6.3, f/7.1, f/8.0,

f/9.0, f/10, f/11, f/13, f/14, f/16, f/18, f/20, f/22

The aperture controls the depth of field in your

image. The depth of field is defined as the area in

front of and behind the subject that is in acceptable

focus. The bigger the opening in the lens (aperture),

the shallower the depth of field (which means that

the area in acceptable focus is very small). Look at

Aperture

The aperture setting controls the size of the open-
ing in the lens that lets light through the lens
into the camera. The bigger the opening, the
more light is allowed to reach the sensor. The
range of openings available is determined by the
lens, not the camera body, which is one of the big
advantages to using a dSLR — you can change
lenses depending on the situation.

The aperture is described using f-stops, which are
fractions made by the focal length of the lens and
the diameter of the opening. The important thing
to know is that the smaller the number, the larger
the opening. So an f-stop of f/2.8 lets in more
light than an f-stop of f/5.6. Each time the size of
the opening is doubled, the lens allows twice as
much light (1 stop) in. Each time the aperture is
halved, it allows half as much light in. This
means that when you change from f/2.8 to f/4.0,
you are letting in exactly half as much light, and
when you change from f/16 to f/11, you

STUCK AND HOT PIXELS There is one thing that needs to be addressed when it

comes to using very long shutter speeds, and that is a specific type of digital noise. Usually

digital noise is only a concern in relation to the ISO setting, but when you keep the shutter

open a long time, there is a different type of noise that is introduced. This type of noise is

commonly referred to as stuck pixel noise or hot pixel noise, but the two are not exactly the

same. Stuck pixels are actually damaged pixels that are going to show up as spots in any

photo no matter the shutter speed, while hot pixels are those that leak over time, showing up

in the longer exposure times, but they can look the same. The longer that you leave the shut-

ter open, the more hot pixels you will see. Many cameras have a long exposure noise reduc-

tion setting that seems to take as long as the exposure to work. That is because the camera is

taking a second photo, just as long as the original but without opening the shutter so that the

hot pixels can be determined and removed from the shot. Check your camera manual for this

setting for your camera.