CHAPTER 5 – LENSES

What are the main functions of a lens on a camera in a surveillance system?

• Brighten dark images

• Provide better lighting

• Defining the field of view

• Define the image sensor format

How does the amount of light passing through a lens affect the quality of the picture in a surveillance system?

• The amount of light does not affect the quality of the picture

• The less light that passes through, the better the quality of the picture

• The more light that passes through, the worse the quality of the picture

• The more light that passes through, the better the quality of the picture

Why is the selection of a lens critical in a surveillance system?

• It only affects the lighting of the image

• It has no effect on the size, shape, and sharpness of the image

• It directly affects the size, shape, and sharpness of the image

• It indirectly affects the size, shape, and sharpness of the image

How does a varifocal lens differ from a fixed lens?

• A varifocal lens offers a range of focal length, while a fixed lens only offers one focal length

• A varifocal lens allows the user to manually adjust the camera's lens, while a fixed lens cannot be adjusted by the user

• A varifocal lens is recommended for outdoor conditions, while a fixed lens is recommended for indoor conditions

• A varifocal lens is not recommended for outdoor conditions, while a fixed lens is recommended for outdoor conditions

In which type of environment is a fixed lens typically used?

• Indoor environments where the iris needs to be adjusted

• Outdoor environments where the viewing angle needs to be adjusted

• Outdoor environments where the scene lighting is constantly changing

• Indoor environments where the viewing angle does not need to be adjusted

Why are zoom lenses recommended for outdoor conditions?

• They offer the best housing for the lens

• They offer a range of focal length that needs manual adjustment

• They automatically adjust the amount of light reaching the camera

• They are normally deployed in areas where viewing angle adjustment is not required

What is the iris and what is its function in a camera?

• A device that controls the aperture of the lens

• A device that controls the sensitivity of the sensor

• A device that controls the shutter time of the camera

• A mechanical device that adjusts the amount of light passing through the lens of a camera

How does the aperture size in the iris affect the amount of light that passes through the lens?

• The aperture size affects the depth of field of the image

• The aperture size does not affect the amount of light passing through the lens

• A smaller aperture size allows more light to pass through, while a larger aperture size allows less light to pass through

• A larger aperture size allows more light to pass through, while a smaller aperture size allows less light to pass through

How does the iris size affect the depth of field in an image?

• A small iris diameter gives a better depth of field

•  A large iris diameter gives a better depth of field

• The iris size affects the shutter time of the camera

• The iris size does not affect the depth of field of the image

How is the iris size measured in a camera?

• In pixels

• In inches

• In F-number

• In millimeters