When it comes to security, the quality of your CCTV (Closed-Circuit Television) camera is paramount. The footage and images captured by your surveillance system will only be as good as the camera itself – and this depends on various factors such as focal length, field of view, resolution, lighting, obstacles and weather. To ensure you get the most out of your camera’s capabilities and have a comprehensive understanding of its range and versatility, it’s important to understand the principles of optics and how cameras work.
The Focal Length
The focal length is the distance between the center of a curved lens to its optical center when focused at infinity. This determines how far and wide your camera can see – expressed in millimetres (mm). A larger focal length number means that angle will be narrower; a smaller number indicates a wider view. Generally speaking, short focal lengths provide wider angles with more detail but less clarity at greater distances, while longer ones offer more focused views over greater distances with fewer details but increased clarity. Security cameras typically come in either 4mm or 6mm lens sizes. A 4mm lens can see up to 6 metres away from its point of origin while a 6mm lens captures footage up to 120ft away which makes it great for monitoring driveways or front entrances.
Field Of View
Field of view refers to what you can see through the camera – both horizontally and vertically. It’s measured in degrees where wide-angle lenses are usually 2.8mm or 3mm, 4mm offers an angle of 61.93 degrees with an approximate line of sight of 120ft at 100m distance while 6mm lenses have an approximate line of sight range up to 120 feet away .
Resolution
The resolution or image quality captured by your camera is determined by pixels per square inch – also referred to as pixel density. The higher this figure is, the sharper and clearer the image will appear onscreen; anything up to 8 million pixels per square inch should provide excellent results., Common resolutions found on security cameras include 2MP (megapixels), 4MP ,5MP ,and 4K Ultra HD (high definition).
Other Factors
In addition to these considerations that affect how clear and how far your camera can see,, other factors like lighting within an area being monitored ,obstacles such as walls or trees blocking footage ,and weather conditions like fog or rainstorms should also be taken into account., Buying high-quality equipment does not guarantee perfect results but getting the best possible set-up certainly increases chances for success.
