LENS FOCUS TEST CHART (72 SECTOR STAR)

REFLECTANCE

The TE121 test chart is designed for

• adjustment of camera lenses

• 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 to channel between greatest

    and shortest focal length, the individual pick-up tubes must be adjusted mechanically in the optical

    axis.

1. Select white channel. Set optical focus at greatest focal length. With shortest focal length and

    divergent focus adjust the pick-up tube in W-channel until optimum focus is achieved. If necessary

    optimize by alternating with optical focus adjustment.

2. With unchanged optical focus adjustment and shortest focal length adjust 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.

At the outer diameter of the sector star there is a resolution of the sector star there is a resolution of

50.5 lines, i.e. 0.65 MHz (625 lines) or 0.64 MHz (525 lines). The unresolved center of the star has a

diameter of 1% of the outer diameter.