LENS FOCUS TEST CHART (36 SECTORS) 16:9 YE148/TE148
The YE148 test chart is designed for
x adjustment of camera lenses
y checking back focal distance
With the aid of a low transmission filter and by means of low level lighting make sure that the camera is not over modulated with the aperture in the open position.
a) Optical focus: Adjust focus of zoom lens at greatest focal length.
b) Back focal distance (lens): Adjust focus at shortest focal length by regulating lens mechanically with adjustment screw and optimize alternatively with a).
c) Back focal distance (pick-up tubes): If focus varies from channel between greatest and shortest focal length, the individual pick-up tubes must be adjusted mechanicallyin the optical axis.
1. Select white channel. Set optical focus at greatest focal length and divergent focus adjust the pick-up tube in W-channel until optimum focus is achieved. If necessary optimize by alternative with optical focus adjustment.
2. With unchanged optical focus adjustment and shortest focal length the red and blue pick-up tube until optimum focus is achieved. Image focus (focus adjustment) is maintained at all focal lengths (zoom-in) and constant distance from object by means of back focal distance adjustment.