The higher the photosensitivity, the better the camera will be able to capture images in low light. This is an important factor to consider when choosing a camera, especially for surveillance purposes where monitoring may need to occur in both well-lit and low light conditions.
The camera automatically switches to black-and-white mode at night, as black and white contrast vision can be better than color. Additionally, turning on IR illumination further improves the resulting image quality. This allows the camera to remain effective even in complete darkness. The illumination level is measured in Lux.
Examples of illumination values:
Moonless night: 0.01 lux
Moonlit Night: (1/4 of the Moon): 0.05 lux
Starlight Night: 0.003-0.1 lux
At night on the street with the full moon: 0.3-0.1 lux
Deep Twilight: 1 lux
The auditorium in the theater: 3-5 lx
Twilight and illuminated highway at night: 10 lx
Warehouses: 75-30 lux
Offices: 50-500 lux
Hotel halls: 100-200 lx
Shops and supermarkets: 1500-750 lux
Daylight on the street in cloudy weather: about 5,000 lux
Daylight on the street in sunny weather: 100000-5000 lux
When manufacturers describe the "visibility" of a camera, they are referring to its ability to capture a minimum level of illumination of the subject or object being monitored. However, this does not guarantee high image quality. It is recommended to choose a camera with a photosensitivity parameter that exceeds the illumination level of the object or subject by several times in order to ensure optimal image quality.
Low-light performance is a system property
Sensor sensitivity is affected by pixel area, lens aperture, exposure time, gain and image processing. A specification expressed only in lux is difficult to compare between vendors because test conditions differ. The useful test is whether moving objects retain detail at the illumination level that actually exists in the scene.
Noise has consequences beyond image appearance
High gain can create a bright but noisy image. That noise increases encoded bitrate and can destabilize motion or AI detection. SmartVision benefits from a cleaner input stream because recording becomes more efficient and analytics receive more consistent detail. Compare day/night mode and sensor size.