Good Cheap Camera Filters
W. Lewis Hyde
Early in the war, Edwin Land realized that color filters for aerial cameras could not be economically produced using conventional methods. The cameras required a Metrogon lens that covered a 93° field at f/6.3 and a yellow or red filter about six inches in diameter, having only a few wavelengths of error from flat. Such a filter often improves contrast by cutting out the light scattered by haze which is predominately blue.
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