Philips VCM8161/00T - Manual (Page 7)

length and thus a different angle of view than the
8 mm F1.3 lens, supplied with your camera. You
will find useful information in the following table
and diagram to help you make the best choice.
The choice of the lens may affect the
illumination range of your camera. Consult the
table below to see which type of lens you require
for your particular application.
To ensure a good picture quality you should use
a lens with an F-value (maximum aperture) of at
least F 4, preferably better.
F-value
of lens
Illumination range (lux)
Nominal Minimum Maximum
0.95 18 1 13,000
1.2 29 1.5 21,000
1.3 34 1.7 25,000
1.4 39 2 28,000
1.6 51 2.5 36,000
1.8 64 3.5 46,000
2.0 80 4 57,000
2.8 156 8 100,000
The diagram in the next column will help you
select the focal length, required to cover the
object or area you want monitored; it shows the
width of the scene visible on the screen with
lenses of different focal lengths at given
distances (camera to object). You can extend
the scope of the diagram by simply multiplying
the values at both axes with "x“
12tnm
16 mm
25 mm
Example:
If the distance camera to object is 21 metres:
simply multiply the value distance camera to
object for 7 metres with 3. Next multiply the
width of the scene, reproduced on the monitor
screen by 3 also.
Focus adjustment_________________
For optimal picture sharpness, the CS-mount
adjustment ring at the front of the camera has
been pre-adjusted in the factory to standard
CS-mount back focus distance. Re-adjustment
of the back focus distance may however be
necessary when the back focus distance for a
particular lens differs slightly from that of the
standard lens, supplied with the camera.
Set the focussing ring of the lens to infinity (this
does not apply when you have a fixed focus
lens).
• Aim the camera at an object which is at least
15 metres (45 feet) away.