Abstract: A color encoding video system such as a single or double tube color television camera has an optical grating low pass filter positioned in a plane substantially adjacent the focal plane of the image pickup tube. A separate and interchangeable image forming objective optical system can be mounted on the body of the camera for focusing an object scene on the photosensitive element of the pickup tube. The filter grating pattern can be stripes or lenticular lenses and has a spatial frequency along the scanning direction limited to a value not greater than the highest spatial frequency available for detection of the luminous signals whereby optical imaging problems are prevented regardless of the aperture opening of the objective optical system.

Abstract: A combination optical low pass filter adapted for use in a single or double tube color television camera is provided with a phase retarding pattern on a transparent substrate. The pattern includes optical elements having a transmissivity which varies with the wavelength of light passing there through so that the optical low pass filter functions as both a phase diffraction and an amplitude diffraction filter. Medium indexed filler material can further supplement the pattern to eliminate any light scattering.