CCTV CCTV Camera Technology and Optics 1 — Questions and Answers
Question 1: What does the term 'focal length' refer to in CCTV camera lenses?
- The distance from the lens to the image sensor where parallel rays converge (Correct answer)
- The maximum distance a camera can detect motion
- The width of the camera's housing
- The power consumption of the camera module
Correct answer: The distance from the lens to the image sensor where parallel rays converge
Focal length is the distance from the optical center of the lens to the image sensor when focused at infinity, determining the field of view.
Question 2: Which camera type is best suited for a wide-area indoor space requiring a 360-degree view?
- Bullet camera
- PTZ camera
- Fisheye camera (Correct answer)
- Box camera
Correct answer: Fisheye camera
Fisheye cameras use an ultra-wide-angle lens to capture a full 360-degree hemispherical view, ideal for large indoor areas.
Question 3: What is the primary advantage of a varifocal lens over a fixed lens in CCTV?
- Lower cost
- Adjustable focal length without disassembly (Correct answer)
- Higher resolution output
- Wider aperture range
Correct answer: Adjustable focal length without disassembly
Varifocal lenses allow the installer to manually adjust the focal length within a specified range, providing flexible field-of-view setup.
Question 4: What does 'WDR' stand for in CCTV camera specifications?
- Wide Dynamic Range (Correct answer)
- Wireless Data Recording
- Wide Depth Resolution
- White Definition Rate
Correct answer: Wide Dynamic Range
WDR (Wide Dynamic Range) allows a camera to capture detail in scenes with both very bright and very dark areas simultaneously.
Question 5: Which sensor type is commonly used in modern IP cameras for converting light into electrical signals?
- CRT
- CMOS (Correct answer)
- LCD
- LED
Correct answer: CMOS
CMOS (Complementary Metal-Oxide-Semiconductor) sensors are widely used in modern IP cameras due to their low power consumption and high integration.
Question 6: What does a lower f-number (aperture) on a CCTV camera lens indicate?
- Narrower field of view
- Less light entering the lens
- Larger aperture allowing more light (Correct answer)
- Higher focal length
Correct answer: Larger aperture allowing more light
A lower f-number indicates a larger aperture opening, which allows more light to reach the sensor and improves performance in low-light conditions.
CCTV CCTV Camera Technology and Optics 1
What does the term 'focal length' refer to in CCTV camera lenses?