SWIR Fixed Lens

Lens for SWIR Fixed Camera

Focal Lengths: 6mm to 100mm.
Aperture Options: F1.4, F1.8, and F2.0.
Image Formats: Compatible with 1″, 1/2″, and 1/3″ sensors.
Aperture Control: Available in manual and variable iris types.
Standard C-mount: Direct compatibility with our C-mount SWIR cameras.
Spectral Range: Optimized for 900-1700 nm SWIR band.

Attostek provides a series of high-performance fixed focal length lenses ranging from 6 mm to 100 mm. All SWIR lens feature lockable focus and aperture rings for stable, repeatable adjustments. All lenses are equipped with a standard C‑mount interface, ensuring full mechanical and optical compatibility with our complete line of C‑mount SWIR cameras.

Model	SWIR0618C	SWIR0814CL	SWIR1214C	SWIR1614C	SWIR2514C	SWIR3514C	SWIR5014C	SWIR10020C
Focal Length	6mm	8mm	12mm	16mm	25mm	35mm	50mm	100mm
Aperture	F1.8	F1.4	F1.4	F1.4	F1.4	F1.4	F1.4	F2.0
Resolution	2MP	2MP	120lp	5MP	80lp	5MP	5MP	100lp
Image Format	1″	1″	1″	1″	1″	1″	1″	1″
Optical Distortion	≤-4.8%	≤-3.6%	≤-1.8%	≤-0.6%	≤-0.96%	≤-0.52%	≤-0.6%	≤0.3%
Dimension	Φ63×64.2mm	Φ69.5×69mm	Φ55×75mm	Φ54×63mm	Φ36.5×54.91mm	Φ36.5×46.73mm	Φ47.2×55.58mm	Φ60×94mm
Flange Focus Length	17.526mm	17.526mm	17.53mm	17.526mm	17.53mm	17.526mm	17.526mm	17.53mm
Back Focus Length	9.42mm	9.65mm	12.68mm	13.72mm	11.46mm	11.76mm	18.28mm	17.92mm
Iris Type	Manual	Manual	Adjustable Aperture	Adjustable Aperture	Adjustable Aperture	Manual	Manual	Adjustable Aperture
M.O.D.	0.1 – ∞m	0.1 – ∞m	0.1 – ∞m	0.3 – ∞m	0.3 – ∞m	0.3 – ∞m	0.5 – ∞m	0.5 – ∞m
FilterThread	M67×0.75mm	M67×0.75mm	M52×0.75mm	M52×0.75mm	M34×0.5mm	M34×0.5mm	M40.5×0.5mm	M58×0.75mm

Model	Image Format	Field Angle			Suitable Distance
Model	Image Format	D	H	V	Suitable Distance
SWIR0618C	1″	105°	93.6°	77°	0.1 – ∞m
	1/2″	67°	55°	43°
	1/3″	51.4°	43°	32°
SWIR0814CL	1″	90.7°	78.4°	62.6°	0.1 – ∞m
	1/2″	53°	44°	33°
	1/3″	41°	33°	25°
SWIR1214C	1″	66.5°	55.2°	42.6°	0.1 – ∞m
	1/2″	36.5°	24°	22°
	1/3″	27°	22°	16.5°
SWIR1614C	1″	53.6°	43.4°	33.2°	0.3 – ∞m
	1/2″	28°	22.5°	16.6°
	1/3″	21°	17°	12.5°
SWIR2514C	1″	36°	28.7°	21.8°	0.3 – ∞m
	1/2″	18°	14°	11°
	1/3″	13°	11°	8°
SWIR3514C	1″	26°	21°	15.7°	0.3 – ∞m
	1/2″	13.2°	10.5°	8°
	1/3″	10°	8°	6°
SWIR5014C	1″	17.2°	14°	10.5°	0.5 – ∞m
	1/2″	8.6°	7°	5.2°
	1/3″	6.6°	5.2°	4°
SWIR10020C	1″	9.3°	7.3°	5.4°	0.5 – ∞m
	1/2″	4.5°	3.6°	2.7°
	1/3″	3.5°	2.7°	2.1°

SWIR Lens Size

6mm f/1.8 Fixed Lens

8mm f/1.4 Fixed Lens

12mm f/1.4 Fixed Lens

16mm f/1.4 Fixed Lens

25mm f/1.4 Fixed Lens

35mm f/1.4 Fixed Lens

50mm f/1.4 Fixed Lens

100mm f/2.0 Fixed Lens

Focal Length

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.

Aperture

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.

Interface

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.

Resolution and MTF

Lens resolution, also known as resolving power, refers to its ability to distinguish between two closely spaced points. To achieve optimal performance, the lens resolution must be properly matched to the pixel size of the image sensor.

Lens resolution is commonly characterized using the Modulation Transfer Function (MTF) curve, which illustrates the relationship between spatial frequency and the transfer function value. The horizontal axis of the MTF curve represents spatial frequency in line pairs per millimeter (lp/mm), indicating how closely two points are spaced. The vertical axis represents the transfer function value, indicating the degree to which two adjacent points can be distinguished.

The MTF value at low spatial frequencies reflects the lens contrast performance, while the MTF at high spatial frequencies indicates the lens resolving capability. An ideal imaging lens exhibits an MTF curve that declines gradually from low to high frequencies.

Maximum Sensor Size

The maximum sensor size determines lens and camera compatibility. The lens projects a circular image circle, while the camera sensor is rectangular, meaning the final saved image is also rectangular. The “maximum sensor size” of a lens refers to the largest image sensor size that the lens is designed to fully cover

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.

When used with a smaller sensor, only the central portion of the image circle is captured, leading to a reduced field of view and narrower angle of view.

Chief Ray Angle

The Chief Ray Angle (CRA) of a lens refers to the angle between the principal ray of the lens and its optical axis. The CRA of a camera sensor indicates the maximum incident angle at which the sensor’s pixels can effectively receive light. If the incident angle of light exceeds the sensor’s designed CRA limit, the light will not be properly captured by the sensor

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.

Depth of Field

Depth of field refers to the axial range in front of and behind the focused plane within which objects can still appear acceptably sharp in an image. This range includes the front depth of field (the clear zone in front of the focal plane) and the rear depth of field (the clear zone behind the focal plane). The sum of these two zones constitutes the total depth of field

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

Q1 : What is SWIR?

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.

Q2 : What exactly is a Short-Wave Infrared (SWIR) lens and how does it work?

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.

Q3 : Why can't I just use a standard visible-light lens for SWIR imaging?

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.

6mm - 100 mm Fixed Focal Length Lens for C-Mount Format Cameras

To meet the diverse application demands of short-wave infrared (SWIR) imaging, Attostek offer a series of high-performance SWIR lenses. This lineup covers focal lengths from 6mm to 100mm and features a wide aperture range of F1.4 to F2.0 as standard, ensuring high signal-to-noise ratio and superior image quality even in low-light conditions. Users can flexibly select different models based on field of view, working distance, and resolution requirements, providing high sensitivity and versatile scene adaptability for SWIR cameras in applications such as security surveillance, industrial inspection, and scientific research.