Infrared Lenses (IR Lenses)

Avantier designs and manufactures custom infrared (IR) lenses for advanced applications in

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• Manufacturing
• Defense and security
• Scientific research
• Medical diagnostics

IR lenses operate beyond the visible light spectrum, capturing and focusing infrared radiation to enable high-precision thermal imaging and detection.

Key IR Lens Types

We offer optical systems across the full infrared spectrum, including:

• Near-Infrared (NIR)
• Short-Wave Infrared (SWIR)
• Mid-Wave Infrared (MWIR)
• Long-Wave Infrared (LWIR)

Each lens type is optimized for its target wavelength range and application.

IR Lens MWIR Lens Germanium MWIR Lens SWIR Lens LWIR Lens Germanium LWIR Lenses NIR Lens Motorized MWIR Lens

Factory Standard (Manufacturing Capability)

SWIR lens MWIR lens LWIR lens NIR lens Wavelength 0.9 um-2.5 um 3 um-5 um 8 um-12 um 0.9 um-1.5 um Focal length 25 mm 50 mm 6 mm 25 mm F/# 2.5 0.94 1 2 Sensor 2/3″ 2/3″ 1″ 2/3″ FOV 25° 13° 128° 25°

Custom IR Lens Options

Avantier specializes in fully customized IR lens systems, from prototyping to volume production.

• Custom Specifications: Tailored to meet your exact performance metrics, from resolution to spectral response.

• Lens Types
  • Aspherical lenses
  • Spherical lenses
  • Cylindrical lenses
  • Custom geometries and assemblies

• Precision Optical Design: Our engineers use advanced simulation software to optimize for:
  • Thermal stability
  • Low distortion
  • Aberration correction
  • High transmission efficiency

• Material Selection Guidance: Based on your target infrared band and operating environment, we select optimal substrates to ensure durability and performance.

• Custom Coatings: We offer anti-reflection (AR) coatings tailored to the target spectral range:
  • Visible
  • NIR
  • SWIR
  • MWIR
  • LWIR
  • Coatings improve optical transmission, minimize reflection losses, and provide environmental protection.
• Advanced Manufacturing: Using high-precision processes like diamond turning, CNC machining, and precision molding, we deliver IR optics with exceptional surface quality and dimensional accuracy.

Material Selection

Our IR lenses are fabricated using infrared-transparent materials, such as:

• Germanium (Ge)
• Zinc Selenide (ZnSe)
• Chalcogenide glass
• Zinc Sulfide (ZnS)
• Silicon (Si)
• Sapphire (Al₂O₃)
• Calcium Fluoride (CaF₂)
• Cadmium Telluride (CdTe) – as needed for specialized applications

These materials offer high refractive indices and are selected for optimal spectral performance and aberration correction. The optical parameters are as follows: Refractive index Transmission spectrum CaF2 1.414@3.5 μm 0.23-9.7 μm Ge 4.033@3.5 μm 2-15 μm Chalcogenide 2.0~3.0@10μm 0.6-20 μm CdTe 2.677@8.0 μm 6-22 μm Sapphire 1.695@3.5 μm 0.2-5.5 μm Si 3.428@3.5 μm 1.36-11 μm ZnSe 2.417@8 μm 0.55-18 μm ZnS 2.223@8 μm 0.42-18 μm

Technical Resources

How Does an Infrared Lens Work?

Unlike visible light, infrared light—also known as infrared radiation (IR)— is undetectable to the human eye and standard optical systems such as conventional cameras or the retina. Infrared lenses are engineered to overcome this limitation by:

• Capturing infrared radiation emitted or reflected by objects in the environment
• Focusing this radiation onto a specialized IR sensor within the camera system

This enables the generation of thermal or infrared images, which visualize temperature differences and energy signatures.

Key Functional Aspects:

• Material transparency: IR lenses are made from materials like germanium or zinc selenide, which are transparent to IR wavelengths but opaque to visible light.
• Wavelength range: Typical operating ranges begin at 700 nm (near-infrared) and extend into the long-wave IR (up to ~14 µm), depending on application.
• Design differences: Unlike standard optical lenses, IR lenses are optimized for minimized chromatic aberration, thermal stability, and high transmission in specific IR bands.

By combining the lens with IR filters, sensors, and camera electronics, the system becomes capable of capturing detailed thermal or IR imagery, critical for applications like surveillance, diagnostics, and industrial monitoring.

Structure of Lens

An infrared imaging lens, often referred to as an objective lens or machine vision lens, is composed of several functional parts:

• Focus Adjustment Ring: Changes the focal distance (working distance) between the lens and the object.
• Iris/Aperture Ring: Adjusts the F-number (f/#) to control light intake and image quality.
• Thumbscrews: Lock settings in place to prevent accidental shifts.
• Lens Information: Printed on the barrel—includes focal length, minimum f/#, and model number.
• Working Distance Range: Indicates the focusing range of the lens.
• f/# Tick Marks: Help set the aperture precisely.
• Filter Thread: Mounting point for filters; adapters may be needed for wide-angle lenses.
• Camera Mount: Connects the lens to a camera (e.g., C-Mount, F-Mount, TFL-Mount).
• Rear Protrusion: Portion that extends into the camera—must avoid sensor or filter interference.
• First and Last Optical Surfaces: Define working distance and optical path.
• Lens Shoulder & Flange Distance: Ensure proper mounting alignment and sensor positioning.
• Image Plane: Where the lens focuses light—typically the camera sensor.

Cooled vs. Uncooled Infrared Detectors

Cooled IR Detectors

• Used in: MWIR and LWIR imaging
• Cooling Required: Yes (often liquid nitrogen)
• Advantages:
  • High sensitivity and image resolution
  • Long detection range
• Applications: Aerospace, defense, high-end scientific imaging

Cooled lenses must align with a cold stop, which increases lens complexity and size but ensures better thermal noise suppression.

Uncooled IR Detectors

• Used in: Mostly LWIR imaging
• Cooling Required: No
• Advantages:
  • Compact, cost-effective
  • Operates at room temperature
• Disadvantages: Lower sensitivity and slower response
• Applications: Civilian use, building inspection, automotive systems

Uncooled IR lenses typically have low F-numbers (f/1–f/2) to maximize thermal signal capture and are optimized for wide fields of view.

Types of Infrared Lenses (IR Lenses)

Infrared lenses are typically categorized by the wavelength range they are designed to capture. Each type is suited for different applications and detector technologies.

Short-Wave Infrared (SWIR) Lenses

• Wavelength: 800– nm
• Key Features:
  • Works with reflected IR light
  • High-resolution imaging
  • Performs well in low-visibility environments (e.g., smoke)
• Applications:
  • Semiconductor inspection
  • Anti-counterfeiting
  • Medical diagnostics
  • Quality control and machine vision

SWIR lenses reveal material properties invisible to visible light systems, such as water absorption and silicon transparency.

Medium-Wave Infrared (MWIR) Lenses

• Wavelength: – nm (3–5 μm)
• Key Features:
  • Captures emitted thermal radiation from hot objects
  • Requires cooled detectors
  • Higher resolution than LWIR
• Applications:
  • Fire detection
  • Engine diagnostics
  • Military target acquisition
  • Long-distance surveillance

MWIR is ideal for scenarios with higher object temperatures and offers superior performance in humid environments.

How to Select the Right Infrared Lens

Matching Wavelength Bands to Application Needs

The first and most critical step is to align the IR lens’s wavelength band with your application’s requirements. Each band offers distinct advantages:

• Short-Wave Infrared (SWIR, 0.9-1.7μm): Ideal when reflected light imaging is paramount. SWIR lenses excel in applications requiring strong penetration through smoke/fog, high contrast, and the ability to capture microstructures. Think semiconductor wafer defect detection, covert night vision, and biometric identification.
• Mid-Wave Infrared (MWIR, 3-5μm): Best suited for high-temperature object thermal radiation detection. MWIR lenses offer high atmospheric transmittance and often provide superior sensitivity compared to long-wave IR. They are perfect for industrial equipment overheating warnings (e.g., kilns) and long-range target identification in border surveillance.
• Long-Wave Infrared (LWIR, 8-14μm): The go-to for perceiving thermal radiation from objects at room temperature without needing an active light source. LWIR lenses are highly resistant to environmental interference. Common uses include human body temperature measurement (e.g., medical screening), power equipment heat leakage detection, and general night security surveillance.

Core Technical Parameters for Optimal Performance

Once the wavelength band is determined, delve into these technical specifications to fine-tune your lens selection:

• Focal Length and Field of View (FOV):
  • For large-area monitoring (e.g., ports, forest fire prevention), opt for wide-angle lenses (e.g., 45° FOV).
  • For long-distance recognition and detailed inspection of remote targets, telephoto lenses (e.g., 75mm focal length) are essential.
  • For dynamic scenes like UAV inspections, zoom lenses offer flexibility, allowing you to balance resolution with an appropriate F-number (typically 0.7-1.2).
• Infrared Resolution and Thermal Sensitivity:
  • Resolution: While 640 x 480 pixels (LWIR) often suffices for most scenarios, x pixels (SWIR) is crucial for precision detection in applications like semiconductor inspection.
  • Net Equivalent Temperature Difference (NETD): A lower NETD indicates higher thermal sensitivity. An NETD of ≤ 40mK (LWIR) allows for the identification of a 0.05°C temperature difference, whereas below 30mK is necessary for sensitive tasks such as medical temperature measurement.
• Optical Materials and Coating Technology:
  • SWIR lenses often incorporate chalcogenide glass or are designed to pair efficiently with InGaAs sensors, aiming for a photon detection efficiency above 70%.
  • LWIR lenses are typically crafted from high-purity germanium glass and require anti-reflection coatings to minimize energy loss and maximize light transmission.

Simple IR lens Selection WorkFlow

StepKey ConsiderationsTypical Parameter Examples1. Fixed BandDetect target temperature/reflection characteristics20-℃ selects MWIR/LWIR2. Select Focal LengthDetection range and coverageWide Angle 45° vs. super telephoto 75mm3. Core PerformanceResolution, NETD, transmittance640 x 480 pixels + 30mK sensitivity4. Test CompatibilityInterface sealing, detector matchingFascia connection dustproof is better than thread

Applications of Infrared Lenses

Infrared lenses are critical components in modern imaging systems, supporting diverse applications across multiple industries. From medical diagnostics to national defense, their ability to detect invisible infrared radiation makes them indispensable for thermal and spectral imaging.

Medical Instrumentation

Infrared lenses are widely used in thermal imaging and non-invasive diagnostics. Equipped with MWIR or LWIR lenses, infrared thermal cameras can detect subtle surface temperature variations on the skin—useful in identifying:

• Inflammation
• Circulatory issues
• Cancerous growths
• Endoscopic systems

Life Sciences

In life sciences and pharmaceutical research, infrared lenses enable precise NIR light focusing for:

• Near-infrared (NIR) spectroscopy
• Chemical composition analysis
• Food quality inspection

Surveillance & Security

Infrared lenses play a pivotal role in night vision and thermal imaging surveillance.

• SWIR lenses enhance visibility in low-light or obscured environments (smoke, fog, darkness).
• LWIR lenses are widely used in thermal cameras to detect intruders and monitor infrastructure in all weather conditions.
• Border security
• Critical infrastructure monitoring
• Law enforcement and crowd control

Aerospace & Defense

Defense systems rely heavily on MWIR and LWIR lenses for:

• Long-range surveillance
• Target acquisition and tracking
• Navigation in low-visibility conditions
• SWIR imaging also supports target recognition and identification, especially in harsh or camouflaged environments.

Industry Use Cases at a Glance

Application Area

Typical Infrared Lens Types

Use Cases

Life Sciences

NIR, SWIR

Spectroscopy, chemical imaging

Security & Surveillance

SWIR, LWIR

Night vision, perimeter monitoring

Medical

MWIR, LWIR

Thermography, diagnostics, endoscopy

Aerospace & Defense

MWIR, LWIR, SWIR

Reconnaissance, threat detection

Future Trends and Technologies

As demand for infrared imaging continues to grow, several key trends are shaping the future of IR lens development:

Enhanced Performance

Advances in optical materials and coatings will lead to:

• Higher IR transmission efficiency
• Lower aberrations and distortion
• Improved resolution and clarity

Miniaturization

With increasing demand for compact devices, IR lenses are being designed for:

• Wearable medical monitors
• Lightweight UAV and drone systems
• Portable inspection tools

Multi-Spectral Imaging

Next-gen IR lenses may combine multiple wavelength bands (e.g., SWIR + MWIR), enabling:

• Simultaneous data capture across the IR spectrum
• Advanced imaging for agriculture, environment, and security

AI & Machine Learning Integration

When paired with AI-powered imaging systems, IR lenses can support:

• Real-time threat recognition
• Automated quality control
• Predictive maintenance in industrial settings

Emerging Applications

As infrared imaging becomes more accessible, new use cases are emerging in:

• Smart agriculture
• Energy efficiency and HVAC diagnostics
• Waste sorting and recycling

In Summary

Infrared lenses are advancing rapidly—enabling smarter, faster, and more accurate imaging across critical sectors. Whether it’s improving patient care, enhancing national security, or enabling better environmental analysis, IR lenses will remain at the forefront of innovation.

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Digital Infrared Filter Comparison Photos

 
This page is designed to help you decide which filter you’d like to be installed in your camera. We recommend you also watch the video which explains the various filter differences and how to manipulate the images in Photoshop. Then download and play with the RAW files or at least open the jpegs in Photoshop and try things out. This should help you decide which filter to have us install.

Watch this video – It should help you decide which IR filter to choose for your infrared conversion.

 
With our digital infrared camera conversion service you have the choice of 6 IR filters. Along with a UV-Vis-IR full spectrum filter, H-alpha Astro filter & UV ultraviolet filter.

The images below were shot with converted Canon DRebel T3i (600D) cameras to show the differences of each filter. The custom white balance was set on the overall scene for standardization purposes. The original RAW and JPEG files are also provided. Please keep in mind that Photoshop & Lightroom may not interpret the white balance properly – you may need to open these RAW files in Canon Digital Photo Professional (DPP).

For further information on our infrared filters and how they perform in different cameras please visit the FAQ page, for even more info please read IR Primer Chapter 4.

Our Filter Options:

Each horizontal row of images is from a different filter. Refer to the Row/Column text for a description.
Clicking a row will expand additional information.

Click to Expand/Collapse Additional Filter Information Normal Camera
(Unmodified camera, like it comes from the manufacturer.)
Download RAW FileView Larger Version
Click to Expand/Collapse Additional Filter Information Deep BW IR
(equivalent to 830nm Filter)
Download RAW File
View Larger Version
Since the image is captured as BW infrared straight out of the camera there is no need to manipulate in photoshop unless you want to fine tune the BW look. This is our strongest IR filter producing the darkest sky and whitest foliage.
Click to Expand/Collapse Additional Filter Information Standard Color IR Filter
(equivalent to Hoya R72 Filter/ Kodak Wratten 89b Filter/ 720nm Filter)
Download RAW File
View Larger Version
A great all around infrared filter choice. Color infrared is possible although not as saturated as our Enhanced infrared filter and only the blue sky effect is possible. Black & white IR photography looks great with good tonal range.
Click to Expand/Collapse Additional Filter Information Enhanced Color IR Filter
(equivalent to 665nm Filter)
Download RAW File
View Larger Version
Allows more color to pass and is especially suited for color IR photography with great saturation and color range. BW also looks quite good although with a bit less contrast without adjustments. Click to Expand/Collapse Additional Filter Information Super Color IR Filter
(equivalent to 590nm Filter)
Download RAW File
View Larger Version
Provides for a super vibrant foliage and intensely colorful sky. With the red & blue channels swapped the foliage takes on a golden orange tone and sky a beautiful royal blue. The most surrealistic, color infrared filter available. You may be surprised to know this IR filter is also great for black & white IR photography, especially if you want full control of all the elements and love tinkering in Photoshop. The video at the top of this page explains this in more detail. Click to Expand/Collapse Additional Filter Information Hyper Color IR Filter
(equivalent to 470nm Filter)
Download RAW File
View Larger Version
Our newest infrared filter variety, Hyper Color,  combines the largest portion of visible light with infrared compared to the rest of our IR filter varieties.  While on paper it only allows a little more visible light to pass with IR compared with our Super Color IR filter (the next filter down the line), the straight from the camera result is much different as you can see.  Secondly, blending more visible with IR gives this filter an advantage for shooting infrared portraits as people retain a more realistic look compared to any of the stronger IR filters we offer.  But, because it is also just as sensitive to infrared as any of our other IR varieties, anything in nature that reflects infrared especially well continues to do so with the Hyper Color filter!     Click to Expand/Collapse Additional Filter Information Super Blue IR Filter
(equivalent to: N/A)
Download RAW File
View Larger Version
This is our 1st patent pending color infrared filter that allows you to capture color IR images with the blue sky straight out of camera without the need for Photoshop channel swaps. Its very unique as it behaves completely differently than all other infrared filters because it actually has 2 distinct pass bands. The super blue filter passes blue light as well as infrared light thus allowing for super saturated blue skies straight in camera!Another great side benefit is it’s transmission of ultraviolet light making it possible to also to photograph UV light with a proper external UV only filter to block the rest of the spectrum. One can also use an external filter to block the blue wavelengths and photograph infrared light, similar to our Standard IR filter.
Click to Expand/Collapse Additional Filter Information Full Spectrum Clear Filter
(equivalent to: N/A)
Download RAW File
View Larger Version
The advantage of a clear full spectrum conversion is the ability to change filters in front of the lens. You can shoot UV, visible, IR and everything in between depending on the filter you use. So you can achieve all of the above images and more, with appropriate filters.The disadvantage is also the fact that you have to use filters in front of the lens and since IR filters are opaque black the viewfinder will be blocked making it harder to compose, meter and focus.This conversion is mainly used in special applications photography like forensics, astronomy, medical, etc.

Now that you are familiar with the available filters lets proceed to the next section:

NEXT – Focus Calibration Options

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