CCTV Lens – CS04012012F2

CS04012012F2 is 4mm CCTV lens Designed for low-light conditions, F1.2 Low F-number CS mount wide-angle lens, 1/2″ 2-Megapixel, IR corrected.

This lens is part of Towin’s CS-Mount Lenses portfolio, providing a compact fixed-focal optical configuration for professional camera systems.

4mm CS-Mount F1.2 Wide Angle IR Corrected CCTV Lens

This 4mm CS-mount wide angle CCTV lens combines a 75° horizontal field of view with a fast F1.2 aperture and IR-corrected optical design. With a 1/2″ image format, fixed 4mm focal length, and manual focus, it is designed for professional CCTV cameras and wide-area monitoring systems that require consistent scene coverage in changing light conditions.

CS-Mount CCTV Lens Core Highlights

• 4mm fixed focal length provides stable and repeatable wide-area framing.
• 75° horizontal FOV captures a broad scene from a fixed camera position.
• F1.2 fast aperture supports brighter imaging in low-light environments.
• 2MP optical resolution is suitable for standard-resolution surveillance systems.
• IR-corrected optics help maintain focus consistency when visible and near-infrared illumination are both used.

CS-Mount CCTV Lens Applications

Core Application Scenes

This 4mm CS-mount wide angle lens is designed for surveillance installations where a relatively broad scene needs to be captured from a fixed camera position. Its 75° horizontal and 57° vertical field of view provides wide coverage without requiring a motorized zoom mechanism, making it suitable for applications where the desired viewing geometry is established during installation.

The F1.2 aperture makes this lens particularly useful for CCTV systems operating under reduced or variable illumination. By providing a fast optical configuration, it can help the camera maintain usable image brightness when ambient light decreases.

The IR-corrected design further extends its suitability to day/night surveillance systems. When a camera switches between visible-light imaging and near-infrared illumination, IR correction is intended to reduce wavelength-related focus shifts and maintain more consistent image sharpness.

Compatible Device List

• 1/2″ CCTV cameras: Designed for camera systems using 1/2″ image sensors and requiring a 4mm fixed focal length.
• Wide-area security cameras: The 75° horizontal FOV is suitable for entrances, corridors, rooms, reception areas, and other defined monitoring zones.
• Low-light surveillance cameras: The F1.2 aperture supports camera systems operating in relatively dim environments.
• Day/night CCTV equipment: IR correction makes the lens suitable for systems incorporating near-infrared illumination.
• Professional CS-mount camera platforms: The CS interface allows integration with compatible CCTV and industrial camera bodies.

For applications where the required viewing coverage depends on installation distance and sensor dimensions, engineers can use the Lens Selection Guide to evaluate the optical configuration before selecting a lens.

Wide-Area Monitoring Applications

The fixed 4mm configuration is useful when camera framing needs to remain consistent across multiple installations. Typical deployment environments include building entrances, retail interiors, office areas, corridors, small warehouses, and general security monitoring zones.

For smart surveillance projects requiring broader system-level integration, this lens can be considered alongside Towin’s Smart Security solutions.

Because the specified distortion is below -25%, this lens should be selected for applications where broad visual coverage is more important than precise geometric reproduction. It is therefore better suited to general surveillance and situational monitoring than metrology or precision measurement.

For projects where distortion characteristics are an important selection factor, engineers can review the Distortion Guide before comparing optical designs.

Optical Selection Considerations

The lens provides 100° diagonal, 75° horizontal, and 57° vertical FOV on the specified 1/2″ image format. The actual scene coverage will depend on camera mounting height, working distance, and sensor geometry.

Since this is a 4mm fixed focal lens, the viewing angle cannot be changed after installation by optical zoom. Engineers should therefore determine the required field of view before choosing the lens. Towin’s FOV Calculator can be used to estimate scene coverage based on focal length and sensor parameters.

For additional information about sensor and lens compatibility, the Sensor Guide provides useful background when matching an optical system to a camera sensor.

Designed for wide-area CCTV surveillance, low-light monitoring, and day/night security cameras requiring a fixed 4mm CS-mount lens.

Frequently Asked Questions

Q: What type of lens is this 4mm CS-mount lens?
A: This 2MP fixed-focal wide-angle CS-mount lens features a 4mm focal length, F1.2 aperture, fixed iris, manual focus, and an IR-corrected optical design.

Q: What is the field of view of this lens?
A: The specified field of view is 100° diagonal, 75° horizontal, and 57° vertical on the supported 1/2″ image format.

Q: Is the 4mm lens a zoom lens?
A: No. It is a fixed focal lens. The focal length stays at 4mm and delivers consistent framing after users install the camera.

Q: What is the advantage of the F1.2 aperture?
A: F1.2 is a fast aperture that allows more light to reach the image sensor, making the lens suitable for CCTV systems operating under relatively low or changing illumination.

Q: What does IR corrected mean?
A: IR correction reduces focus shifts between visible and near-infrared wavelengths and helps maintain more consistent focus when the camera uses IR illumination.

Q: What cameras are compatible with this lens?
A: The lens supports 1/2″ image formats and adopts a CS mount. It works with compatible professional CCTV cameras and other CS-mount camera platforms.

Q: Is this lens suitable for precision measurement?
A: It is not primarily intended for precision measurement because the specified distortion is below -25%. Applications requiring accurate geometric reproduction should use a lens specifically designed for low distortion.

Q: Where can this 4mm wide angle lens be used?
A: Typical applications include indoor CCTV, entrances, corridors, retail areas, office monitoring, small warehouses, and day/night security cameras requiring broad fixed-angle coverage.

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