Lenses and image formation

Lenses and image formation - o Lenses and image formation...

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o Lenses and image formation Light source emitting light in all directions, some waves come into contact with convex lens ,are refracted and brought together on the imaging surface some distance behind the lens o Electromagnetic spectrum – shortest wavelengths have highest energy Measuring light intensity o Luminance – the amount of energy emitted or reflected by an extended light source Expressed in candelas per sq meter 1 candela – the amount of light. .? o Contrast and reflectance Contrast is a measure of the diff b/w the highest and lowest luminance in a scene, so it represents relative rather than absolute luminance The reflectance of a surface is the proportion of incident light that it reflects Contrast in natural scenes depends on surface reflectance – the contrast b/w a piece of coal and a sheet of paper is constant at different luminance levels Light = 100 coal = 25%,paper =75% C=.5 Light =1000, coal =25%, paper = 75% C=.5 Eye evolution
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Lenses and image formation - o Lenses and image formation...

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