PCM Systems & Services

The network camera that you need depends on what you need to it to do, and where you need it to be. Will you need the camera for indoor use only, or for indoor and outdoor use?

Usually, outdoor network cameras have to regulate the amount of light that the image sensor is exposed to, as lighting conditions vary with the weather conditions and the time of day. For this reason, outdoor cameras require an auto-iris lens which is normally powered by the camera, and this can prevent problems such as over-exposure which can be caused by bright sunlight. The auto-iris lens replicates what the iris in the human eye does when we move outside from indoors, or vice versa.

An outdoor camera will also need to have protective housing, unless of course the camera design has the housing already in-built. Housings are also available for indoor cameras that need to be protected from dusty or damp conditions, and also to protect against the cameras being vandalised or interfered with. Some cameras already incorporate anti-vandal and tamper-proof features, therefore eradicating the need for additional external housing.

So, whether the network cameras are required for indoor or outdoor use, read on for more information that should give you more of an idea on which type of camera is best for you....

Fixed Network Cameras:

A fixed network camera has a fixed field of view (normal, telephoto and wide-angle) once it is put into position for use, and may have a fixed or varifocal lens.

A fixed camera is the more traditional camera style, where the camera is clearly visible, and therefore the direction in which it is pointing is also visible. This type of camera would be favourable in situations where making the camera visible would be to the users benefit.

Fixed cameras can usually have their lenses changed, and are able to be installed in housings suitable for indoor or outdoor locations.

Fixed Dome Network Cameras:

Fixed dome network cameras are sometimes referred to as 'mini-domes', and consist of a pre-installed camera inside a small dome housing. These cameras are designed to point in any chosen direction.

These cameras are designed to be discreet and tamper-proof as it is difficult for intruders to see which direction the camera is pointing in, and are usually mounted on a wall or a ceiling.

A varifocal lens is often provided so that the user can adjust the cameras field of view. It is unusual for this type of camera to have an exchangeable lens due to the limited space inside the dome housing.

Pan Tilt Zoom (PTZ) and Pan Tilt Zoom Dome Cameras:

All pan, tilt and zoom instructions are sent over the same network cable as video transmissions, which eliminates the need for RS-485 wires that are required for an analogue PTZ camera.

PTZ and PTZ dome cameras can pan, tilt and zoom in and out of a required area or object, either manually or automatically. They are alike in their capabilities, but there are some differences between them.

For example, a mechanical stop in PTZ network cameras mean that the camera does not have a full 360-degree continuous pan, so is not able to follow a continuing motion around the camera. Also, PTZ network cameras are not able to follow continuous automatic operations, or what is known as a 'guard tour', where the camera moves from one preset place to another automatically.

Other possible features of a PTZ or PTZ dome cameras include:

- Electronic image stabilisation - beneficial in outdoor installations as the cameras can be at risk from movement from the weather or traffic. This feature assists in the reduction of the effects of vibration in the images.

- Privacy masking - this allows privacy for all areas that shouldn't be picked up by surveillance. In a PTZ or PTZ dome camera, this function can allow the privacy masking even when the viewing angle changes.

PTZ dome network cameras cover a wide area as they are more flexible in their pan, tilt and zoom movements. They allow a 360-degree, continuous pan, and usually tilt to 180 degrees. They are excellent for discreet placement due to the design and mounting. Again, it is also difficult to see which way the camera is facing.

The PTZ dome network cameras do allow continuous operation in 'guard tour' mode, so the camera can automatically move from one preset position to the next. The user can decide if this should be in a certain order, or at random. Some models allow for up to 20 of these tours to be set, and can be activated at different times of the day. In this mode, just one PTZ dome network camera can do the work of 10 fixed network cameras. It is, however, worth considering that only one location will be covered at any given time.

This type of camera is best mounted on a ceiling if for indoor use, or on a pole or side of a building if required for outdoor use, and are generally controlled by an operator.

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