What is a Day Night Camera?
Definition:
Unlike traditional cameras that struggle in low light, day/night cameras are built to adapt. During the day, they capture full-color, high-resolution video. As light fades, these cameras automatically switch to a black-and-white mode, often activating to “see” infrared illumination in complete darkness. This seamless transition ensures there are no blind spots, providing continuous monitoring for your home or business .
(Source: Securecomm)
This allows the same camera to deliver accurate color during the day while capturing clear monochrome images in extremely low-light or total darkness when paired with IR illumination.
2. The sensors inside day/night cameras (CMOS/CCD) are naturally sensitive to near-infrared wavelengths (700–1,000 nm), giving them up to 4× more low-light performance at night compared to standard color-only cameras.
When the IR-cut filter is removed, the sensor uses this extra IR energy to produce brighter, more detailed nighttime video.
3. High-quality day/night cameras use IR-corrected lenses so that visible and infrared light focus at the same point, preventing the image from going out of focus when switching to night mode.
When the IR-cut filter is removed, the sensor uses this extra IR energy to produce brighter, more detailed nighttime video.
1. Day/night cameras use a mechanical IR-cut filter (ICR) to switch between true-color imaging in daylight and high-sensitivity infrared imaging at night.
Facts about day/night cameras
Day Night Cameras
Day/night cameras switch from color to infrared night vision automatically, providing clear surveillance in all lighting conditions.
Clear surveillance, day and night
Day/night demystified explained
Mark Peterson, Theia Technologies
Mere mortals see only visible light, whereas security cameras can see both visible and infrared
(IR) light. Many light sources including the sun create both visible and IR light. Security
cameras use color filters (blue, green, and red) to create a color image but each filter also
allows IR light to pass through onto the sensor, muddying the colors. Since most lenses are
designed for visible light only, most security cameras have an IR filter to block the IR light. This
filter improves both the color fidelity and focus sharpness of the image.
But those cameras considered true day/night can physically switch the IR filter out of the light
path allowing the camera to see both naturally occurring and artificially created IR light. These
cameras require day/night lenses to keep the scene in focus both day and night. Day/night
lenses are generally more expensive because of the added complexity of focusing a broader
color spectrum (from visible through IR) onto the sensor.
What is a true Day/Night camera?
A true day/night camera will have a movable IR filter. During day performance, the IR filter is in
place blocking all the IR light, creating a nice color image. In this case, the IR filter (represented
in brown on the chart above) will block all IR light greater than about 750nm. At night, when the
amount of light decreases, the IR filter is replaced with a clear glass dummy filter. The clear
glass allows all available visible and IR light to reach the sensor and be recorded.
© Theia Technologies 2009 Page 2 of 3.
So removing the IR filter makes each pixel sensitive to IR light, improving the light sensitivity,
but at the expense of color fidelity. To counteract the degraded color in night mode, the
software for most day/night cameras de-saturates the colors creating a monochrome image.
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