This article contains answers to general terminology questions regarding security cameras.
The aperture is the iris or hole that lets light into the camera. The larger the hole the more light can enter the camera. The more light that can enter the camera the better it can see in poor light and the brighter the picture will be.
Bit-rate is the amount of data used to store one second of video. This is measured in bits per second and is typically measured in kilobits or megabits.
Dynamic range is a measurement of the range of bright and dark parts of an image the camera can record. The bigger the dynamic range the more of the image a camera can record e.g. camera cable of recording the very bright scene outside the window in a room as well as the dimly lit room itself has high dynamic range.
A dome camera is a form factor off security cameras that are a dome or half a sphere. The benefits of this form factor are that it can be easily installed in many locations discreetly.
Field of View (FoV) is the term used to describe how much of a scene a camera can see. A narrow FoV typically found when a camera is zoomed in will show only a small part of a scene e.g. the door entrance to the room. A wide FoV will show a large part of a scene e.g. the entire room and not just the entrance door.
Video is made up of still images played back quickly in quick succession. Each still image is known as a frame and the number of frames played in a second (FPS) will dictate how smooth the motion in the video is. The higher the frame rate the smooth moving things will appear. TV shows are typically 30fps, movies 24fps, and security cameras are variable between 1fps and 30fps.
Infrared (IR) illuminators are lights that can be used to illuminate a dark scene. Infrared is invisible to the human eye but can be seen by cameras. Infrared illuminators allow cameras to see in the dark when humans can not.
Shutter speed is how long the camera collects light for when it is taking a picture. As a video is a series of pictures (frames) this setting applies to the video frames. The longer the camera collects light for the better it can see in poor light.
This means the camera has a variable focal length which can be adjusted. The focal length is a technical measurement of a camera lens and affects the Field of View (FoV). The longer the focal length (typically measured in millimetres) the more zoomed in the camera will be.