Absolute Beginner's Guide to Digital Photography

Green pixels outnumber red and blue by a ratio of 2:1. The reason for this is that

human vision is most sensitive to green, which is why 50 percent of the pixels in a

CCD are dedicated to this color.

A Bayer mask isn’t the most efficient way to capture color for several reasons:

■ Three pixels are required for each ”virtual” pixel. Three separate pixels

devoted to red, green, and blue are combined in software to create a virtual

pixel in the center of these sensors. The end result is a virtual pixel that repre-

sents the light and color at that point in the CCD. The problem is that pixels

are wasted in this system, and the space between pixels adds up over the

width of the CCD. In addition, only a percentage of green is captured. The

lost part of green results in a loss of sharpness.

■ A square shape isn’t the most efficient. By placing three pixels together to cre-

ate a virtual pixel in the center, the amount of space between the actual pix-

els and the virtual pixel is sizable. Fuji has developed a SuperCCD technology

using hexagonal pixels to reduce this blank space, but even this technology

results in a loss of sharpness.

■ Software interpolation—software must combine imperfect red, green, and

blue values into an imperfect color. During this software-driven interpolation,

color artifacts and mosaic problems can appear (see Figure 2.4).

Programmers have been successful at reducing common mosaic problems,

but this issue still occurs.

CHAPTER 2 ADVANTAGES AND DISADVANTAGES OF DIGITAL CAMERAS 19

FIGURE 2.4
Color artifacts
and mosaic pat-
terns occur with
Bayer mask
cameras.