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Back Focus Adjustment
APPENDIX B: BACK FOCUS ADJUSTMENT
When to adjust back focus
Back Focus refers to the distance from the rear lens element to the camera focal plane. In
most cases, it is required to adjust back focus only when the camera's lens cannot hold focus
throughout its zoom range.
Required tools
:
•
Back focus adjuster (in the IP Camera's package)
•
Test chart / contrasting object
To adjust back focus
1.
Set the camera on a stable mount, with the test chart or object at least 75 feet
(23 meters) away (or as far as possible).
2.
Make sure the iris is wide open.
It is advised to keep the environment in a low light condition.
3.
Adjust the focus to infinity (
∞
).
4.
Turn the zoom to the extreme telephoto position, and then focus on the subject.
5.
Set the zoom to wide-angle position.
6.
Loosen the back focus ring's retaining screw shown in figure B1 with the supplied back
focus adjuster, and adjust the back focus ring to sharpen the picture.
7.
Repeat steps 3 ~ 6 until focus stays the same throughout the zoom range.
8.
Tighten the back focus ring's retaining screw to fix the ring.
Figure B7.1 Back focus steps
