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