CCTV lens – CS281212718A4

CS281212718A4 is 4-Megapixel resolution CCTV lens, 1/2.7″ 2.8-12mm manual zoom and focus lens, F1.8-C aperture CS mount, DC auto iris, IR corrected.

2.8–12mm 4MP CS-Mount IR Corrected CCTV Lens

This 2.8–12mm CS-mount CCTV lens is designed for 1/2.7″ cameras and delivers 4MP resolution with a 154°–38° diagonal field of view. Its 106°–30° horizontal FOV, F1.8-C aperture, DC auto iris and IR corrected optical design make it suitable for flexible wide-angle CCTV and day/night surveillance applications.

CS-mount IR corrected CCTV lens Core Highlights at a Glance

• 2.8–12mm manual varifocal range provides adjustable framing from very wide coverage to a narrower viewing angle.
• 4MP optical resolution supports higher-detail surveillance compared with standard 3MP configurations.
• 154°–38° diagonal FOV provides broad scene coverage at the 2.8mm wide end.
• F1.8–C aperture with DC auto iris supports exposure control under changing illumination.
• IR corrected optical design makes the lens suitable for day/night CCTV systems using infrared illumination.

CS-mount IR corrected CCTV lens Applications

Core Application Scenes

The 2.8–12mm focal-length range allows this lens to cover a wide range of CCTV installation requirements without changing the lens after installation.

At the 2.8mm wide end, the lens provides a 106° horizontal field of view and 75° vertical field of view, making it suitable for broad-area surveillance such as entrances, corridors, retail spaces, reception areas and indoor monitoring zones.

When the focal length is adjusted toward 12mm, the horizontal field of view decreases to approximately 30°, allowing the installer to create a tighter composition around a particular monitoring area. This makes the lens useful when the exact installation framing cannot be finalized before deployment.

The 4MP resolution provides higher image detail than the 3MP versions in this lens family, making it suitable for surveillance systems where increased image information is required while retaining a flexible varifocal design.

The F1.8–C aperture and DC auto iris allow the optical system to respond to changing lighting conditions. Combined with the IR corrected design, the lens can be integrated into day/night surveillance systems where infrared illumination is used during low-light operation.

With a 0.2m M.O.D., the lens can also accommodate relatively close-range monitoring scenes.

Designed for 4MP CCTV surveillance, wide-area security monitoring and day/night applications requiring adjustable framing and IR compatibility.

Compatible Device List

• 1/2.7″ 4MP CCTV cameras
• CS-mount surveillance cameras
• Day/night security cameras
• Indoor CCTV camera systems
• Retail surveillance cameras
• Commercial security systems
• Entrance and access monitoring cameras
• General-purpose video surveillance equipment

For other sensor and focal-length configurations, TOWIN’s CS-Mount Lenses collection provides additional options for CCTV and security imaging.

Focal Length and Field of View Selection

The manual zoom range allows installers to select the appropriate framing according to the actual camera position and surveillance target.

At the wide end, the 106° horizontal FOV can capture a large area with one camera. At the telephoto end, the narrower 30° horizontal FOV allows the installer to concentrate the image on a smaller region.

For system planning, TOWIN’s FOV Calculator can be used to estimate the viewing area based on sensor size and focal length.

If the working distance and required target coverage are already known, the Focal Length Calculator can help determine a suitable focal-length range.

4MP Resolution for Higher-Detail Surveillance

With a specified 4 Megapixel resolution, this lens is intended for CCTV systems that require more image detail while maintaining the flexibility of a varifocal optical configuration.

The combination of 4MP resolution and a 2.8–12mm focal range allows the same lens configuration to be used for different surveillance layouts. Installers can adjust the focal length according to the actual scene instead of selecting a fixed focal length before installation.

This is particularly useful for commercial and indoor security systems where camera mounting positions may remain fixed while the required viewing composition varies.

IR Corrected Optical Design

The lens incorporates an IR corrected optical design, which is important for day/night surveillance systems that use infrared illumination.

When a CCTV camera changes between visible-light operation and infrared-assisted night operation, optical focus can shift if the lens is not designed to accommodate the different wavelengths. IR correction is intended to improve focus consistency across the relevant imaging wavelengths.

Combined with the DC auto iris and F1.8 maximum aperture, this configuration is suitable for surveillance environments with changing illumination.

For projects involving infrared imaging or optical configuration selection, TOWIN’s Lens Selection Guide provides additional information about selecting a suitable lens.

Wide-Angle Coverage and Distortion Considerations

The lens provides a 154° diagonal field of view at the wide end, together with a specified distortion range of -75% to -3.5%.

These specifications indicate that the optical design prioritizes wide-area scene coverage rather than geometric accuracy. This can be appropriate for general CCTV surveillance, where capturing a broad scene is more important than maintaining straight-line geometry.

The lens should therefore not be positioned as a low-distortion machine vision lens. Applications involving dimensional measurement, precision inspection or geometric analysis should consider an optical design with controlled distortion characteristics.

TOWIN’s Distortion Guide provides additional background on how distortion affects image geometry.

Frequently Asked Questions

Q: What camera sensor is this lens designed for?
A: This lens is designed for a 1/2.7″ image format and uses a CS mount. The camera should support the specified sensor coverage and CS mechanical interface.

Q: What is the focal-length range of this lens?
A: The lens has a 2.8–12mm manual varifocal range, allowing the installer to adjust the image framing after the camera has been mounted.

Q: What is the horizontal field of view?
A: The horizontal FOV ranges from approximately 106° at 2.8mm to 30° at 12mm.

Q: What is the diagonal field of view?
A: The diagonal field of view ranges from approximately 154° at the wide end to 38° at the 12mm end.

Q: Is this lens suitable for 4MP CCTV cameras?
A: Yes. The lens is specified with 4MP resolution and is designed for 1/2.7″ cameras using a CS mount.

Q: What does IR corrected mean?
A: IR correction is designed to improve focus consistency when the lens operates across visible and infrared wavelengths, making it suitable for day/night surveillance systems.

Q: Does this lens have automatic iris control?
A: Yes. It uses a DC auto iris. The aperture can respond to changes in illumination when connected to a compatible camera and control system.

Q: Is this lens suitable for precision machine vision inspection?
A: It can be used for general imaging or monitoring, but its specified -75% to -3.5% distortion indicates that it is designed primarily for wide-angle surveillance rather than precision geometric measurement. Low-distortion optical configurations are more appropriate for applications where dimensional accuracy is critical.

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