CCTV CCTV Camera Technology and Optics 2 — Questions and Answers
Question 1: What is infrared (IR) cut filter used for in a day/night CCTV camera?
- To block UV rays during daytime recording
- To remove IR light during daytime to improve color accuracy (Correct answer)
- To amplify IR illumination at night
- To prevent lens fogging in cold weather
Correct answer: To remove IR light during daytime to improve color accuracy
The IR cut filter is mechanically removed at night to allow infrared light to reach the sensor, and is present during the day to maintain accurate color reproduction.
Question 2: Which camera feature allows automatic horizontal tracking of a moving subject?
- Auto iris
- Auto tracking PTZ (Correct answer)
- Auto white balance
- Auto gain control
Correct answer: Auto tracking PTZ
Auto tracking PTZ cameras use video analytics to automatically pan, tilt, and zoom to follow a moving subject across the camera's field of view.
Question 3: What is the purpose of Back Light Compensation (BLC) in CCTV cameras?
- To extend battery life during night operation
- To improve visibility of subjects in front of bright backgrounds (Correct answer)
- To reduce noise in low-light footage
- To compensate for lens distortion
Correct answer: To improve visibility of subjects in front of bright backgrounds
BLC adjusts the exposure for a specific area of the image to prevent subjects in front of bright light sources from appearing as silhouettes.
Question 4: A CCTV camera rated IP66 is protected against:
- Low-voltage surges and dust only
- Powerful water jets and dust ingress (Correct answer)
- Submersion up to 1 meter depth
- Vandalism and physical impact
Correct answer: Powerful water jets and dust ingress
IP66 rating means the camera is fully dust-tight (6) and protected against powerful water jets from any direction (6).
Question 5: What is the function of 'auto iris' in a CCTV camera lens?
- Automatically adjusts focus based on subject distance
- Automatically adjusts aperture to maintain consistent exposure (Correct answer)
- Automatically switches between color and monochrome
- Automatically pans the camera toward motion
Correct answer: Automatically adjusts aperture to maintain consistent exposure
An auto iris lens automatically adjusts the aperture opening in response to changing light levels to maintain proper image exposure.
Question 6: Which of the following best describes a 'covert' CCTV camera?
- A camera designed to withstand extreme temperatures
- A camera disguised or hidden to avoid detection (Correct answer)
- A camera with built-in motion detection
- A camera mounted on a PTZ platform
Correct answer: A camera disguised or hidden to avoid detection
Covert cameras are intentionally concealed within everyday objects or disguised to avoid detection by subjects under surveillance.
CCTV CCTV Camera Technology and Optics 2
What is infrared (IR) cut filter used for in a day/night CCTV camera?