Understanding Camera Sensor Sizes: 1/1.8" vs 1/2.8" and Low-Light Lux Ratings

When selecting CCTV cameras for security applications, one critical factor to consider is the size of the camera sensor. Two common sizes are 1/1.8" and 1/2.8". In this technical guide, we’ll explore the differences between these two sensor sizes and how they impact low-light performance, using Lux ratings as our metric.

Sensor Size: 1/1.8" vs 1/2.8"

The size of a camera’s image sensor is expressed in fractions of an inch. For example, a 1/1.8" sensor measures 0.5625 inches diagonally (1 / 1.8 = 0.5556). Similarly, a 1/2.8" sensor measures 0.3542 inches diagonally.

At first glance, the difference in size may seem small, but it has significant implications for image quality and low-light performance:

1. Light Gathering: A larger sensor can capture more light than a smaller one due to its increased surface area. The 1/1.8" sensor is approximately 58% larger than the 1/2.8" sensor. This means that cameras with 1/1.8" sensors will perform better in low-light conditions, requiring less illumination to achieve the same level of image quality.

2. Pixel Size: With a larger sensor, individual pixels are also larger. This allows for greater light capture per pixel, further enhancing low-light performance. In comparison, the smaller 1/2.8" sensor has smaller pixels, which can lead to increased image noise and reduced detail in challenging lighting conditions.

Low-Light Lux Ratings

To quantify a camera’s low-light capabilities, we use Lux ratings. Lux measures the intensity of light falling on a surface, with one lux being equal to one lumen per square meter. A lower Lux rating indicates better performance in dimly lit environments:

• 1/2.8" sensor: Typical CCTV cameras with 1/2.8" sensors have an ILP (Interrupted Light Projector) rating of around 0.006 lux.
• 1/1.8" sensor: Cameras equipped with 1/1.8" sensors often boast ILP ratings as low as 0.002 lux, demonstrating their superior ability to capture images in extremely dark conditions.

In practical terms, this means that a camera with a 1/1.8" sensor can produce usable video at approximately one-third the illumination level of a camera with a 1/2.8" sensor.

Choosing the Right Camera Sensor Size

When selecting CCTV cameras for your security system, consider the lighting conditions in your environment:

• For well-lit areas or daytime surveillance, either sensor size will suffice.
• In low-light situations or nighttime applications, opt for cameras with 1/1.8" sensors to ensure optimal image quality and lower Lux ratings.

Always assess your specific requirements and consult with a professional CCTV installer to determine the most appropriate camera sensor size for your needs.

📊 CCTV System Design Reference Infographic