M42-Mount SWIR Fixed Lens
- Focal length options: 25 mm / 40 mm / 100 mm
- Aperture options: F1.4, F1.6, F1.9
- Compatible sensor format: Φ28 mm (maximum image circle)
- Aperture control: Adjustable iris
- Standard M42 mount: Directly compatible with the SWIR151B series SWIR cameras
- Spectral range: Optimized for the 900–1700 nm short-wave infrared band
| Model | SWIR2519L | SWIR4016L | SWIR5014L |
| Sensor Format | Φ28 mm | Φ28 mm | Φ28 mm |
| Mount Interface | M42 | ||
| Focal Length | 25 mm | 40 mm | 50 mm |
| Aperture | F1.9 | F1.6 | F1.4 |
| Resolution | 70 lp/mm | 120 lp/mm | 100 lp/mm |
| Distortion | ≤1.6% | ≤-0.8% | ≤1.5% |
| Back Focal Length | 18.16 mm | 25.21 mm | 17.55 mm |
| FOV | 58° | 37° | — |
| Working Distance | 0.2 – ∞ m | 0.25 – 1 m | 0.43 – 1 m |
| Dimension | Φ52 × 62.5 mm | Φ60.2 × 71.5 mm | Φ60 × 64.9 mm |
| Filter Thread Size | M49×0.75 mm | M58×0.75 mm | M52×0.75 mm |
| Flange Focal Length | 46.5 mm | ||
| Designed Wavelength | 900–1700 nm | ||
| Aperture Type | Adjustable Iris | ||
Focal length refers to the distance between the optical center (rear principal point) of a lens and its imaging focal point, serving as a key performance parameter of the lens. It determines the angle of view: the shorter the focal length, the wider the field of view and the broader the observable range; the longer the focal length, the narrower the field of view and the more concentrated the observation area.
The aperture controls the amount of light entering the lens—a larger aperture results in a brighter image. This parameter directly affects exposure time and, consequently, the camera’s response speed. In daytime shooting, if the light is too strong, the aperture can be narrowed to prevent overexposure; at night or in low‑light conditions, the aperture can be widened to increase light intake, ensuring optimal imaging performance under varying lighting conditions.
The optical lens interface refers to the standardized mechanical mount connecting a lens to a camera body, determining compatibility and ensuring precise alignment for correct optical focus onto the image sensor. In industrial applications, C-mount and CS-mount are generally employed with cameras featuring smaller sensor sizes, while F-mount is typically used for larger sensors. Additional interfaces commonly found in line-scan cameras include M42, M58, and M72 mounts—essentially threaded connections of specified diameters.
C-mount lenses represent the established standard in machine vision, compatible with cameras housing image sensors up to approximately 20 mm (1.5 inches) in diagonal dimension. This interface supports a wide array of specifications across focal lengths, resolutions, and working distances. All SWIR fixed lenses provided by Attostek are designed with C-mount connectivity.
When used with a larger sensor, the edges of the sensor extend beyond the lens’s image circle, resulting in dark corners or black borders around the photo.
To ensure optimal imaging performance, it is generally required that the lens CRA should match the sensor CRA, with the lens CRA not exceeding that of the sensor.
Three primary factors influence depth of field: aperture size, working distance, and lens focal length. Increasing the depth of field can be achieved by:
- Reducing the aperture size (i.e., using a larger f-number)
- Increasing the working distance
- Using a lens with a shorter focal length
The word SWIR is an acronym meaning Short Wavelength InfraRed, also frequently referred to as shortwave infrared. SWIR generally refers to the wavelength band of light between 900nm and 2500nm.
A SWIR lens is an optical lens specifically designed to focus light in the short-wave infrared spectrum, typically between 0.9 and 1.7 micrometers (µm). The lens works by collecting SWIR light reflected from objects and converging it onto a specialized sensor, such as an Indium Gallium Arsenide (InGaAs) detector, which then converts the photoelectric signal into a grayscale image.
While it is physically possible to mount a visible lens on a SWIR camera, the image quality will be severely compromised. Standard optical glasses and anti-reflective coatings are optimized for the visible spectrum (400-700nm). When used for SWIR, these lenses suffer from significant optical aberrations, particularly chromatic aberration, and a sharp decrease in resolution. This happens because the glass elements fail to focus the longer SWIR wavelengths to the same point, resulting in a blurred image. A true SWIR-optimized lens uses special glass types and coatings to ensure all SWIR wavelengths focus correctly, delivering high contrast and resolution.
25 mm – 50mm Fixed Focal Length Lens for M42-Mount SWIR Cameras
To meet the diverse application needs of short-wave infrared (SWIR) imaging, Attostek has launched a series of high-performance SWIR lenses. The SWIR lenses with M42 optical mount feature a focal length range of 25 mm to 50 mm and come standard with large apertures of F1.4/F1.6/F1.9, ensuring high signal-to-noise ratio and excellent image quality even under low-light conditions. Users can flexibly select the appropriate model according to their requirements for field of view, working distance, and resolution. This series of lenses provides high sensitivity and outstanding scene adaptability for SWIR cameras in applications such as security surveillance, industrial inspection, and scientific research.