|Analog Gain and CCD Flare
The trade-off in using analog gain is that increasing the luminance of the LEDs has a tendency to aggravate CCD flare. The advantage of further brightening the LEDs must be continually weighed against losses of shadow and highlight detail. Flare is most noticeable as a halo in sharply contrasting areas adjacent to each other such as in the bright rail against the dark background, below left. It can be made more visible by equalizing the image's tonal scale, images below right.
The adjusted image below, another Kodachrome shot, shows severe haloing above the subject's head.
The picture detail, below, is of a bush in a deep shadow silhouetted against a sun-lit rocky landscape. The aggressive use of analog gain has turned the black bush into a muddy brown. Some of the thinner branches have even disappeared. The flare is also noticeable in the shadow area closest to its demarcation with the sun-lit area and dissipates with distance from the bright area. Some flare would be present even without the use of analog gain.