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Appendix D: 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,
What requirements
Tools required when carrying out back focus adjustment include:
1. Back focus adjuster (in the IP Camera’s package)
2. Test chart / contrasting object
How to adjust back focus
Step 1:
Set the camera on a stable mount, with the te
st chart or object at least 75 feet (23
meters) away (or as far as possible).
Step 2:
Make sure the iris is wide open. Therefore,
it is advised to keep the environment in
low light condition.
Step 3:
Adjust the focus to infinite far (
∞
).
Step 4:
Turn the zoom to the extreme telephot o position, and then fo cus on the subject.
Step 5:
Set the zoom to wide-angle position.
Step 6:
Loosen the back focus ring’s retaining scr
ew with the supplied adjuster, and adjust
the back focus ring for sharp picture.
Step 7:
Repeat steps 3 ~ 6 until focus can st
ay the same throughout the zoom range.
Step 8:
Tighten the back focus ring’s reta ining screw to fix the ring.
