2.9mm Tapered Cone Lens

Product Brief  

BOSHI Optical Technology presents the PL‑02934H‑M12, a high‑performance wide‑angle fixed lens engineered for 1/4" format sensors. With a 2.9mm focal length and a fast F3.4 aperture, this lens delivers a generous 119° diagonal field of view, making it ideal for applications that require broad scene coverage in tight spaces. Its all‑glass construction (3 elements) ensures thermal stability and consistent image quality across a wide temperature range. The lens features a controlled chief ray angle of less than 6.63°, which minimises colour shading and maintains colour accuracy when paired with modern CMOS sensors. Despite its compact 8.9mm total track length, the mechanical back focal distance of 2.46mm offers flexible integration with standard M12 mounts. BOSHI Optical Technology has carefully balanced the optical design to achieve a TV distortion of ‑14.27% – a typical value for ultra‑wide lenses that can be digitally corrected – and a relative illumination of 30% at the edge, ensuring usable brightness even in low‑light conditions. This lens is a cost‑effective solution for embedded vision, security cameras, in‑vehicle surround‑view systems, and industrial inspection where a 2.9mm focal length and wide 119° coverage are essential. Whether you are designing a dashcam or a doorbell camera, the PL‑02934H‑M12 offers the optical performance and mechanical robustness that BOSHI Optical Technology is known for, with full compatibility with 1/4" sensors and M12 interfaces.

Product Detailed Description  

1. Optical Parameter Analysis  

Focal Length (EFL): 2.9 mm ±5% – a short focal length that enables an ultra‑wide perspective, critical for capturing large areas from close distances. This 2.9mm focal length is the primary determinant of the lens’s angular coverage.  

Aperture (F/NO): F3.4 ±5% – a moderate speed that balances light throughput with depth of field, suitable for both indoor and outdoor environments with varying illumination.  

Image Circle & Sensor Format: Maximum image circle Φ4.65 mm, specifically designed for 1/4" sensors (standard diagonal ~4.5 mm). The 1/4" format ensures full utilisation of the sensor’s active area without vignetting.  

Field of View: Diagonal 119°, Horizontal 81.6°, Vertical 58° – this 119° field of view provides an expansive window, reducing the number of cameras needed for full panoramic coverage.  

TV Distortion: ‑14.27% (barrel type) – a predictable and repeatable distortion pattern that can be easily corrected in software, enabling rectilinear output for machine vision tasks.  

Chief Ray Angle (CRA): <6.63° – a low CRA that matches modern sensor microlens arrays, suppressing cross‑talk and colour shift, especially at the 119° field edges.  

Mechanical Back Focal Length (BFL): 2.46 mm ±0.2 – provides sufficient clearance for IR‑cut filter or cover glass, while maintaining a compact M12 mount footprint.  

Total Track Length (TTL): 8.90 mm ±0.3 – a slim profile that allows integration into space‑constrained housings.  

Relative Illumination: 30.0% – ensures that corner brightness remains acceptable, facilitating reliable edge detection in surveillance and automotive applications.  

Mount: M12 thread (standard) – offers quick mechanical attachment and broad compatibility with off‑the‑shelf lens holders.

2. Performance Advantages  

Ultra‑Wide yet Correctable Distortion: The ‑14.27% TV distortion is a deliberate design choice for wide‑angle optics. Instead of attempting zero distortion (which would increase size and cost), BOSHI Optical Technology provides a highly consistent distortion profile that can be fully compensated by digital image processing, preserving the 2.9mm focal length advantage without sacrificing peripheral resolution.  

Low CRA for Sensor Compatibility: With a chief ray angle below 6.63°, the lens works seamlessly with 1/4" sensors that have shallow pixel wells. This minimises vignetting and colour non‑uniformity, ensuring that images captured at the full 119° field of view maintain natural colour balance from centre to corner.  

Thermally Stable Glass Construction: The 3‑element all‑glass design (not plastic) guarantees stable focus and resolution over temperatures from ‑20°C to +70°C, making it reliable for outdoor surveillance and in‑vehicle cameras where temperature fluctuations are common.  

Compact Integration: The 8.9mm TTL and M12 mount allow direct drop‑in replacement for existing camera modules. The mechanical back focal distance of 2.46 mm leaves room for optional filters, while the F/3.4 aperture offers a good depth of field for objects ranging from 0.3 m to infinity, reducing the need for auto‑focus mechanisms.  

Consistent Illumination: Although relative illumination is 30%, this is typical for a 119° lens; the gradual roll‑off can be compensated by sensor gain or digital shading correction. The lens’s low F‑number ensures adequate central brightness, enabling usable images even under 10‑lux conditions.

3. Application Areas  

Surveillance & Security: Dome cameras, doorway viewers, and corridor monitors benefit from the 119° field of view to cover wide areas with a single unit. The 2.9mm focal length is optimal for indoor monitoring where room corners need to be captured without blind spots. The M12 mount simplifies retrofitting into existing security housings.  

Automotive & Mobility: Surround‑view systems, blind‑spot cameras, and rear‑view cameras for vehicles exploit the wide 119° diagonal to eliminate blind zones. The rugged glass construction and stable optical performance over temperature align with automotive qualification requirements.  

Machine Vision & Robotics: For object detection, navigation, and pick‑and‑place guidance, the lens’s predictable distortion and low CRA enable accurate metric measurement after correction. The compact 8.9mm TTL allows integration into drone payloads or handheld scanners.  

Consumer Electronics:Smart doorbells, VR/AR headsets, and 360° conferencing cameras leverage the 1/4" sensor compatibility and wide field of view to deliver immersive experiences. The F/3.4 aperture provides sufficient depth of field for face recognition at varying distances.  

Industrial IoT & Embedded Vision: With its fixed focal length and simple M12 interface, this lens is ideal for inspection systems on production lines, where a 119° view can inspect large PCB panels or packaging surfaces in a single frame. BOSHI Optical Technology supports customisation of the mechanical back focal length to accommodate different sensor cover glasses, further extending the lens’s versatility.  

Throughout all these applications, the core attributes – 2.9mm focal length, F/3.4 aperture, 1/4" sensor format, 119° field of view, low TV distortion, controlled chief ray angle, and M12 mount – ensure that BOSHI Optical Technology’s lens delivers consistent, high‑quality imaging with minimal post‑processing effort. This product is a prime choice for engineers seeking a balance between wide coverage, compact size, and cost efficiency.