Adjusting the back focus – Axis Communications 2420 W/Lens User Manual
Page 59
AXIS 2420 User’s Manual
Lenses and Advanced Focusing
59
Adjusting the Back Focus
Your AXIS 2420 is supplied with the back focus roughly set to accommodate a reasonable
level of focus throughout the complete focusing range. However, if you are dissatisfied
with the quality of focusing at a specific plane (or at several planes) within the focusing
range, you may need to make some fine adjustments to the back focusing of the lens. This
is performed by adjusting the focus and zoom rings of the camera lens, as described below:
Procedure
1. With the Focus Ring set to the Far-focus (F,
∞
)
position, aim the camera at a subject
over 30 metres away.
2. Set the lens assembly to wide angle, and adjust the back focus by loosening the Lock
Ring and then turning the lens assembly. Continue to turn the lens assembly until you
achieve optimum image clarity
3. Check that you obtain sharp pictures at various zoom grades and various distances.
Note:
If possible, it is better to perform this adjustment in low light conditions, or with a filter covering
the front optic. This will ensure the iris is fully open to give the smallest depth of field, and there-
fore the best result.