Hitachi V-21W - Manual (Page 25)

14
Lens flangeback adjustment
When operating a zoom lens, if the focus is not precisely aligned at both the telephoto and wide angle
extremes of the lens, the flangeback (distance from the lens mounting plane to the focal plane) is adjusted.
This adjustment is generally required only once unless the lens is replaced.
Reference
Refer to the lens operating instructions regarding the component positions for flangeback adjustment.
Flangeback adjustment
1. Set the lens iris for manual operation.
2. Open the iris. Set a flangeback adjusting
chart about 3 meters distant and adjust the
lighting to obtain the correct video output
level. If the video level is too high, use a
CC/ND filter or electronic shutter.
3. Loosen the Ff ring setscrew.
4. By hand or motor, set the zoom ring to the
telephoto position.
5. Observe the flangeback chart image and
turn the distance ring to adjust the focus.
6. Set the zoom ring to the wide angle position.
7. Turn the Ff ring and adjust the focus. Use
care not to turn the distance ring.
8. Repeat this process until focus is obtained at
both telephoto and wide angle settings.
9. Securely tighten the Ff ring setscrew.
Also, see the lens operating instructions.