Introduction to electric zoom lens

An electric zoom lens refers to a new type of lens that uses an electric motor with integrated control cards and software to adjust the zoom level. It allows users to achieve focus and obtain the clearest image by observing the live image on a computer screen. These lenses feature automatic alarm protection, effectively preventing mechanical failures.

Electric zoom lenses come in two types: dual-variable and tri-variable lenses. A dual-variable lens uses motorized drive for both focal length (f) and focus (Focus), while the iris (IRIS) is automatically controlled by the camera signal, thus having an automatic aperture. A tri-variable lens has motorized drive for focal length, focus, and iris. Generally, dual-variable lenses offer slightly better performance than tri-variable lenses, but they tend to be slightly more expensive.

Common lens types include manual/automatic iris fixed-focus lenses and automatic iris zoom lenses.

1. Manual/Automatic Iris Fixed-Focus Lenses
   • Manual iris lenses: Used in environments where lighting conditions remain relatively constant, such as indoors.
   • Automatic iris lenses: Used in environments with significant light variations, like outdoors.

Fixed-focus lenses can be categorized into standard lenses and wide-angle lenses:

• Wide-angle lenses: Suitable for wider viewing angles at shorter distances.
• Standard lenses: Suitable for moderate viewing angles and distances.

2. Automatic Iris Zoom Lenses
   • Zoom lenses can have different zoom ranges, such as 10x, 6x, and 2x. They can also be categorized into manual zoom and electric zoom (with motorized iris and automatic iris).
   • Zoom lenses can be categorized by sensor size, such as 1/3", 1/2", or 1".

When selecting a zoom lens, the principle is that the lens specifications should not be smaller than the camera's. For example, a 1/2" lens can work with a 1/3" camera, but a 1/3" lens cannot be used with a 1/2" camera.

An electric zoom lens is typically designed with a C/CS mount to work with standard box cameras. It allows for manual control of zoom, focus, and aperture. Electric zoom lenses usually have higher zoom ranges, with common options being 6x, 7x, 10x, with focal lengths generally under 100mm. Higher zoom lenses, like 15x, 16x, 20x, 22x, have focal lengths between 100mm and 300mm. Some can reach beyond 300mm, even exceeding 1000mm, making them suitable for long-range surveillance and observation.