Closed Circuit TV (CCTV) Cameras
Specialist and Extreme Environment CCTV Surveillance Cameras
Westminster have a range of specialist CCTV surveillance cameras
which are able to operate effectively in any harsh, hostile or general
purpose outdoor environments from freezing arctic conditions to the
heat and dust of the hottest desert.
Rugged environmental housings protect the camera and lens against
rain, snow, dust, humidity, corrosion, chemical pollutants, extreme
temperatures, and other environmental hazards.
Cameras can be provided which are intrinsically safe for use in
inflammable environments; such as petrochemical plants or munitions
factories etc., or cameras, which are explosion proof or even able
to resist ballistic attacks, where not only the weather but the
general environment is hostile such as border control or urban street
surveillance.
Specialist CCTV surveillance cameras are available for highly
corrosive atmospheres and marine environments and cameras which can
operate in extreme pressures either deep under water or at high
altitudes.
Lens Selection
Selecting the right lens for any CCTV surveillance system is
probably one of the most confusing yet critical elements of any
camera installation.
Firstly the correct mounting for the camera must be chosen e.g.
C or CS (adapter rings are available to assist with this)
Next the lens must be chosen to suit the CCD image size i.e. 1/3"
or 1/2" or 2/3" (note: the same size or bigger can be used but not a
smaller size for example a 2/3" lens will fit 1/2" or 1/3" camera but
only a 2/3" lens will fit a 2/3" camera)
The type of Iris control must then be selected depending upon the
lighting levels in the area to be observed. Where the area is indoors
and the lighting is constant and will not fluctuate a manual iris
can be selected. However in most situations an auto-iris will be
needed, which can adjust to the changing light conditions in order
to provide the clearest possible images.
The area that probably causes the most confusion and errors
however is the selection of the correct focal length. A low focal
length will give a wide field of view but objects, particularly in
the distance, will be small - This is useful for general observation
of larger areas but will not be so useful for detailed monitoring.
A large focal length will give a narrow field of view but will
provide a much more detailed 'close up' view - This is useful for
providing detailed observation of a particular area or object, such
as a doorway or for providing a more positive identification of a
person at a distance.
A varifocal lens will enable the required view to be set up on
site by manually adjusting the focal length within the lenses range
and is very useful for many applications where the exact focal length
may be difficult to determine prior to installation.
However the best option in many cases is to have a fully functional
camera fitted with a electrically operated zoom lens by which means
an operator can have a wide angle view for general observation but
should a more detailed view be required the camera can be zoomed in
for close up observation.
In practice the selection of the correct lens can be a complex
issue, requiring specialist understanding of the implications.
Westminster has considerable experience in this field and are happy
to provide advice as required.
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To view our related Jet Infra-Red Cameras product as a PDF please click Jet Infra-Red Cameras.
To view our related Sentry Scope product as a PDF please click Sentry Scope.
To view our related Vista PowerDome Range product as a PDF please click Vista PowerDome Range.
To view our related Colour Bullet Camera product as a PDF please click Colour Bullet Camera.
To view our related Covert Camera product as a PDF please click Covert Camera.
To view our related Vari Focal Colour Dome Camera product as a PDF please click Vari Focal Colour Dome Camera.
For more information - please click here to contact us.
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