settings and allows you to have consistency in
exposures no matter what camera you use. The
ISO setting is based on the film speeds used in
traditional photography, giving photographers a
constant measurement of how sensitive to light
the film was. Because the light sensitivity of the
sensor in a digital camera can’t actually be
changed, the ISO is adjusted by amplifying the
signal received by the sensor when light strikes it.
The more the signal is amplified, the higher the
ISO rating and the less light is needed.
The downside to this amplification is that digital
noise can be introduced into the image as the sig-
nal is amplified more. Because this book is allthe guitar and the hands in Figure 2-7, and you can
see that while the guitar is in focus, the right hand
isn’t. This is because I used an aperture of f/2.8,
creating a very shallow depth of field.
When out photographing subjects that need long
shutter speeds or when you need to get the whole
scene in focus (as with landscapes), you need to
use smaller apertures in order to create deeper
depths of field.
ISO
The ISO is the setting that determines how sensi-
tive the camera’s sensor is to light. The ISO set-
ting gives you a starting point for the exposure
ABOUT THIS PHOTO I needed to use a wider aperture to get the most light possible through the lens and
freeze the fast fingers of the guitar player. However, at the same time, the shallow depth of field meant that while
the guitar was in focus, the right hand that was just in front of it wasn’t. Taken at 1/160 second, f/2.8, and ISO 1600.
2-7