Photoshop CS3 RAW

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CHAPTER NINE

ABOUT CHROMATIC ABERRATIONS

Figure 9-29 shows a shot taken by

professional photographer Richard

Morgenstein with a Canon 10D and a

14mm wide-angle lens. Although the

chromatic aberrations are not visible at

first glance, magnification will probably

show some annoying anomalies in the

edges of the chrome headlights.

Reducing Chromatic Aberrations with

Camera Raw

To use Camera Raw to reduce chromatic

aberrations in images such as this:

Identify a likely area near the outer 1.

perimeter of a likely candidate. An

example would be an image shot with

a wide angle lens in bright lighting

conditions with sharp edge detail.

Magnify the area using Camera Raw 2.

navigation tools. Select the Zoom tool

and hold your cursor over the area

you wish to magnify. Click and drag a

rectangle around the area you wish to

magnify, as enlarged in Figure 9-30,

then release the mouse.

In the magnified image shown in 3.

Figure 9-31, you can clearly see the

color fringing so typical of this type

of chromatic aberration. (When light

passes through glass, different color

wavelengths are sometimes separated

and shifted in focus ever so slightly. To

visualize this, think of a common prism

and the rainbow it produces. This shift

Chromatic aberrations show up as anomalous color shifts,

mostly on the outer perimeter of images, in areas with distinct

edge transitions. They are common when wide-angle ...