Absolute Beginner's Guide to Digital Photography

As you use Photoshop and digital photography more often, you will need to ensure

that you have the most accurate color setup by tweaking Color Settings. Most digital

cameras rely on sRGB. Only the higher-end cameras provide the richer Adobe RGB

color space. Always try to use Adobe RGB if your camera can capture in that color

space. These color spaces matter significantly when printing with a high-end inkjet

printer. You can read more about this in Chapter 18, “Printers and Printer

Resolution. ”

The CCD Image Sensor

The CCD (charge-coupled device) image sensor was invented in 1969 and introduced

to the public in 1974. The CCD sensor is the most common sensor used for TV cam-

eras because it provides high-quality, low-noise images. When reading from such a

sensor, the pixel values (charges) are transported across the sensor, line by line, and

then shifted into an analog-to-digital converter, turning each pixel’s value into a

digital value (see Figure 2.2).

CHAPTER 2 ADVANTAGES AND DISADVANTAGES OF DIGITAL CAMERAS 17

FIGURE 2.2
A light-sensitive
image sensor
shifts pixel val-
ues along rows
to the processor.

Ver tical charge Transfer (shift),

e.g. every 20ms

Duration approx. 500μs

Ver tical shift into the

Read Out Register

Horizontal (serial) Read Out

(e.g. within 64μs per row)

This amazing invention has two specific problems: manufacturing and power drain.

Producing CCD sensors is very expensive, as special laboratories and machines are

required to manufacture these sensors.

CCD sensors also consume power at a rapid rate. Even though the CCD chips in con-

sumer-level cameras are only 1/3-inch across, they still drain power quickly.