In the realm of CCTV (Closed-Circuit Television) systems, selecting the right lens is crucial for ensuring optimal surveillance coverage, clarity, and performance. Among the common focal lengths available, 2.8mm and 4mm lenses stand out as popular choices for various applications.

Understanding Focal Lengths

Focal length is a fundamental parameter in photography and optics that determines the angle of view, depth of field, and magnification of a lens. In CCTV systems, focal length directly influences the surveillance area’s width (horizontal field of view) and the distance at which objects can be clearly identified.

2.8mm Lens:

• Angle of View: Typically around 90° to 120° (depending on the lens design).
• Surveillance Coverage: Ideal for small to medium-sized spaces such as elevators, staircases, corridors, and small offices.
• Clarity at Distance: Provides clear images up to approximately 4-8 meters, with objects beyond this range appearing blurrier or less distinct.
• Depth of Field: Shallow, meaning objects at different distances from the lens may not all be in focus simultaneously.

4mm Lens:

• Angle of View: Generally around 70° to 90°.
• Surveillance Coverage: Suitable for medium to large-sized spaces such as conference rooms, shops, and small yards.
• Clarity at Distance: Offers clearer images up to approximately 6-12 meters, with better detail recognition at further distances compared to the 2.8mm lens.
• Depth of Field: Moderate, providing a reasonable balance between foreground and background focus.

TOWIN’s CCTV Lens Products

TOWIN, a professional optical lenses supplier, offers a comprehensive range of CCTV lenses, including both 2.8mm and 4mm options. Their lenses are designed with precision engineering and advanced coating technologies to ensure superior performance and durability.

1. M12/S-Mount Lenses

TOWIN’s M12/S-Mount lenses, also known as “board lenses,” are miniature in size and feature a standard M12X0.5 thread for direct mounting onto PCB cameras. These lenses are versatile and suitable for a wide range of applications, including:

• Wide Angle Lenses: Available in 2.8mm focal length, offering a broad field of view for comprehensive surveillance in confined spaces.
• Low Distortion Lenses: Designed to minimize image distortion, ensuring accurate representation of the scene.
• IR Corrected Lenses: Perfect for day/night security cameras, providing clear images in both daytime and low-light conditions.

2. CS-Mount Lenses

TOWIN’s CS-Mount lenses are designed for CCTV cameras, network cameras, and IP cameras, featuring a flange focal distance of 12.526mm. These lenses come in various focal lengths, including 4mm, and offer:

• Fixed Focal and Vari-Focal Lengths: Allowing users to adjust the focus manually or automatically based on surveillance needs.
• Manual Iris, DC Auto Iris, and P-Iris Types: Providing flexibility in controlling the amount of light entering the camera, crucial for maintaining image quality under varying lighting conditions.
• Multi-Coating Technology: Enhancing light transmission and reducing reflections, resulting in sharper and clearer images.Recommended Reading:How Many Megapixels Does a CCTV Lens Have?

Choosing Between 2.8mm and 4mm Lenses

When deciding between a 2.8mm and 4mm CCTV lens, consider the following factors:

1. Surveillance Area Size: For small to medium-sized spaces, a 2.8mm lens may suffice. However, for larger areas requiring broader coverage, a 4mm lens is preferable.
2. Clarity at Distance: If identifying objects or individuals at further distances is crucial, a 4mm lens offers better clarity and detail recognition.
3. Depth of Field Requirements: In scenarios where both foreground and background objects need to be in focus, a 4mm lens provides a more suitable depth of field.
4. Budget and Installation: While 2.8mm lenses are generally more affordable and easier to install in confined spaces, 4mm lenses offer enhanced performance at a slightly higher cost.

Conclusion

Both 2.8mm and 4mm CCTV lenses have their unique advantages and applications. The choice between them ultimately depends on the specific surveillance requirements, including the area size, clarity needs, and budget constraints. TOWIN, as a professional optical lenses supplier, offers a diverse range of CCTV lenses, including both 2.8mm and 4mm options, designed to meet the diverse needs of security professionals and end-users. By understanding the product parameters and characteristics of TOWIN’s lenses, users can make informed decisions to ensure optimal surveillance performance.