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An Overview of True Day/Night, Infrared IP Cameras and Infrared Lighting

One of the most common reasons for installing a security camera system is to monitor your premises day and night. In most scenarios, this means an infrared (IR) camera that copes well with poorly lit scenes.

Almost every IP camera has some way of producing images in low or no light.

Low light image optimisation technologies utilise a variety of techniques to improve image quality. These technologies improve footage in poor lighting conditions, but do not offer a true day/night solution. As a result, your mileage may vary with these systems. In addition, these technologies often require a trade-off with other quality factors such as noise, motion blur, or processing speed.

If you want round-the-clock monitoring that’s not going to let you down, you need a camera with infrared light capability.

How do infrared cameras work?

Infrared light is outside the range of light which humans can see. Light is an electromagnetic spectrum, and ‘visible’ light – the colours that we can see – is only a tiny part of that spectrum.

electromagnetic spectrum showing wavelenghts from gamma to radio

IP cameras with true day/night functionality use infrared-sensitivity to create a black and white image with objects illuminated that we can see. By using infrared light outside the visible spectrum, these cameras provide high quality footage in complete darkness. Therefore, there are few scenarios in which a camera with IR is unable to provide an adequate image.

For an IR camera to provide accurate colour image in daylight conditions it needs to have an infrared cut filter. This filter blocks infrared light during daylight, then when it’s dark the filter is removed to produce images with infrared illumination.

If you find a camera with true day/night functionality, without a filter this results in colour distortion. For example, under fluorescent lights in an office:

Most professional security cameras now contain an IR cut filter.

For an infrared IP camera to work, it also requires an infrared lighting source.

Some cameras can see infrared if they are used with separate external infrared lamps, while others come with integrated IR LEDs. Any IR-sensitive camera will ‘see’ infrared light however it is shone.

What to consider when choosing a true day/night camera

Firstly, think about what purpose the camera needs to fulfill. Not all cameras which are good in the daytime are also ideal at night, and vice-versa. Be clear on the use case for your need and choose appropriately (we can help!)

Let’s have a look at which factors to bear in mind when choosing a security camera.

Wavelength

There are two infrared wavelengths commonly used in surveillance. The numbers don’t matter but their pros and cons do.

  • 850nm infrared light has a slight red glow – not very useful if you want the camera to be hidden
  • 950nm IR light is roughly 50% less powerful, but doesn’t give out a glow and is therefore used for covert surveillance

Integrated lighting

Some cameras come with integrated infrared LED lamps.

The advantage of this is that the camera can provide an infrared image out of the box.

Cameras with IR typically have the integrated LEDs positioned around the lens. The disadvantage of this layout is that the LEDs can lead to uneven lighting that result in sub-optimal image quality. The build-up of heat from these lamps can also encourage insects to take up residence, so a good cleaning routine will be beneficial.

Almost all IP cameras with in-built infrared work at the 850nm wavelength.

Effective distance

Most integrated infrared lighting uses small LED lamps and may only have an effective illumination distance of 15–30m, plenty for most applications, but not all. Bear this in mind if you are planning to cover a wide field of view with just one camera.

If you think you will need more lighting, it would be better to install separate infrared lighting from a manufacturer like Raytec.

Remember that a camera’s infrared capabilities will, for most applications, be used for less than half the day. Make sure you check the daylight capabilities of your camera also meet your requirements.

Other practical considerations

Infrared cameras do not work well when placed behind glass. The infrared lighting reflects off the glass and floods back into the camera, resulting in a nearly useless image.

Also bear in mind that materials reflect light differently in infrared than they do in visible light. For example, trees and grass reflect a lot more infrared light than they do visible light.

Make sure you test your camera in both day and night conditions. Sometimes an image that looks good during daylight hours might not meet your requirements when it switches to infrared.

In summary

An infrared IP camera can produce usable security footage during both the day and night.

Now you understand what IR is and what to consider when looking for an infrared camera. If you bear in mind wavelength, reflections and effective distance when choosing your device, you’re on the right track.

For some help choosing a solution for your site, contact us. We can provide you with a design guaranteed to meet all your requirements.

Published on February 21st, 2011 by Kevin Bowyer

2 Responses to “An Overview of True Day/Night, Infrared IP Cameras and Infrared Lighting”

  1. Shashi says:

    Thanks for this incredible information on daynight infrared camera features.

  2. vilig says:

    cant you test the ones that are cheaper, such the cheapest i[ cameras from regular sometimes remanufactered and sold at cut rates to defect repair dealers.