3.5 Vignetting

The vignetting test can be applied to all generic gray and white balance cards.

- Select the test chart.
- Select the test (Vignetting Analysis).
- Open the test image.
- Click Analyse.

The vignetting test can be applied also to any evenly illuminated smooth surfaces. The focus of the lens should be set to infinity.

The vignetting test computes the light falloffs in the RGB color space and in the Y channel. The light falloffs are relative to the highest intensity of the test image. The light falloffs in the RGB color space are expressed in percentages of the highest intensity. The light falloff in the Y channel is expressed in f-stops (EV).

The vignetting test draws four plots. The first three plots include the light falloffs of red, green, and blue channels. The fourth plot includes the light falloff of the Y channel.

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