-- Kevin Kelm |
![]() | This image shows what a typical viewer would see at a sunset; the sky is bright, and the land and tree are very dark-- nearly sillouhetted. This idea proposes that a camera can selectively darken and brighten specific regions of the image in the same frame for improved detail in the image. This isn't necessarily for normal photography conditions, but is definitely desireable for surveillance, effects, and some commercial photography. |
The key is an extra step in the normal shoot sequence (an SLR camera is shown here); the camera has a CCD image sensor above the eyepiece, which feeds invert/contrast circuitry, which drives a transparent LCD panel in front of the film. That panel can selectively transmit light on to the film plane behind it. |
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![]() | When the trigger is pressed, the aperature sensor CCD is exposed. | ![]() |
![]() | The aperature control circuit inverts the black and white image, and applies a curve to darken the dark areas, lighten the light areas, and leave the midrange more or less alone. | ![]() |
![]() | The shutter closes, the aperature sensor and eyepiece mirrors move out of the way, and the shutter is opened for a longer time than the shutter speed indicates so that more light can be collected for the dark areas of the image; the bright areas are protected from overexposure by the LCD being darkened at those locations. |
The resulting image has fine detail in the bright areas, in the midranges, and even what would normally be dark shadows. NOTE that the image still has full film resolution; it is only the exposure levels that are limited to the resolution of the internal LCD panel. | ![]() |