When it comes to recording overnight, there are several ways that cameras can do this. Infrared is essential when recording overnight. Day/Night recording is available on the dome, fixed dome, bullet, box, and PTZ security cameras.
The camera can be a true day/night (TDN) with a mechanical IR cut filter (ICR), digital day/night, which adjusts electronically without a filter, or it can have IR LEDs (light-emitting diodes). Some cameras have IR LEDs surrounding the lens to provide illumination. Black and white cameras can also record in low light settings.
True Day/Night Cameras
During the day, infrared wavelengths are transmitted to the camera, and without a filter, it can be construed as a color modification, reducing the image clarity.
Most true day/night (TDN) cameras, however, have a mechanical (ICR) infrared cut filter removable (Note: The industry jargon is usually “IR cut”). When the filter is put in place, it filters the wavelengths, improving the quality of the image by showing only the “visible” light, removing the “infrared” light from the spectrum.
When the camera senses low lighting, it automatically removes the filter that intercepts the infrared waves. When the filter is removed, the camera starts recording in black and white. Without color, there is no need for the IR cut filter. The IR waves cannot be seen by the human eye, but advanced cameras can catch the infrared waves reflecting off objects.
True day/night cameras offer top performance in both day and night situations. The Veilux SVS-60CDNRD is a great example of a TDN.
Day/Night Cameras (Digital)
Digital day/night cameras allow for viewing in both day and night conditions, without the use of an IR cut filter. During the day it records in color, adjusting electronically to offer similar benefits to TDN, but with a slightly lower cost. Once it becomes dark, the camera digitally switches to black and white.
When the camera switches to black and white, it solely depends on the lighting and infrared waves reflecting off objects to capture the image.
The best way to see how digital day/night cameras perform is to check their LUX rating. The LUX rating determines how much light is needed for the cam to see at night. There are quite a few cameras available that only need a minimal amount of light to see at night.
For some cameras, the ambiance from the starlit sky is enough to attain a nice image at night. When choosing a camera, be sure to check out the specification sheet and check what LUX the camera operates at. Here’s an article where we mention LUX and the other important elements to look for in a spec sheet.
Cameras with IR LEDs
Some cameras come with infrared LEDs surrounding the lens. These LEDs will emit their own light to illuminate an area. These cameras are ideal for areas with minimal light available. If you choose to, you can even place these cameras in a total blacked-out area and receive great coverage.
The best advice to give for these cameras is for you to check the distance that the IR LED beams can be shot. The IR LEDs can range anywhere from 20 meters all the way up to 70 meters and beyond. Once again look at the spec sheet and make sure the camera you’re considering will cover your required range.
The cameras will operate in color during the day and once the sensor detects increasing darkness the camera will switch over to night vision. Traditionally at night, you can stand in front of the cameras and can see the IR LEDs giving off a faint red glow.
The Samsung SCO-2120R offers 230 feet of night vision range with IR illumination.
Some cameras offer an IR cut filter and IR LED illumination, such as the GeoVision GV-BL110D, resulting in a true image during the day and illumination at night.