4mm Lens for Thermal Imaging Camera – Wide-Angle Infrared Precision
The 4mm infrared lens is a specially designed wide-angle optic for 640×512 thermal imaging cameras. It offers an excellent balance between field of view and imaging clarity, allowing users to capture more scene details in close- or medium-range monitoring applications. Whether used for drone thermal vision, industrial inspection, or public security systems, this 4mm lens delivers stable and precise performance.
Table of Contents
High-Performance Germanium Optics
Unlike visible light lenses, infrared lenses require materials with high transmission in the long-wave infrared (LWIR) range. This 4mm thermal lens is made from premium germanium glass, featuring an advanced anti-reflection coating to ensure over 95% infrared transmittance. It maintains a clear and consistent thermal image even under challenging environmental conditions such as dust, fog, or low light.
Wide Field of View
With a 4mm focal length, this lens provides a wide field of view (FOV) — ideal for applications requiring large-area monitoring. When installed on a 640×512 detector with a 12μm or 17μm pixel pitch, it can cover a wide scene with minimal distortion, making it suitable for:
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Drone thermal imaging and mapping
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Search and rescue operations
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Industrial equipment temperature observation
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Short-range security surveillance
Precision Machining and Durable Housing
The lens adopts high-precision CNC machining for the metal mount to ensure reliable alignment with the camera’s optical axis. The mechanical housing is treated with an anti-oxidation finish, providing long-term durability even in outdoor or high-humidity environments. Each lens undergoes strict optical and mechanical testing to ensure consistent focus and stability.
Easy Replacement and Compatibility
Some customers prefer to replace or upgrade their thermal camera lenses to adjust the field of view. The 4mm infrared lens supports easy installation for compatible 640×512 thermal camera cores, including FLIR, iRay, Guide, or custom OEM modules that use the same mount standard.
Before replacing, please confirm:
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The lens interface type (e.g., M34, M45, or custom thread)
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The detector’s pixel size (12μm / 17μm)
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Whether the camera is radiometric (temperature measuring) or non-radiometric (imaging only)
For non-radiometric imaging, the 4mm lens can be directly replaced after manual focusing. For radiometric cameras, recalibration may be required to maintain temperature accuracy.
Applications
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UAV / drone thermal imaging systems
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Police and fire department monitoring
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Industrial inspection and temperature detection
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Building diagnostics and energy audits
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Nighttime security and perimeter surveillance
Key Features
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Focal length: 4mm
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Wide-angle field of view
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Material: High-transmission germanium
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Coating: AR coating for LWIR (8–14μm)
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Mount type: Custom or standard thread (optional)
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Compact and lightweight design
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Compatible with 640×512 thermal imaging modules
Reliable Quality and Support
We provide original 4mm infrared lenses with strict optical inspection and compatibility testing. If you are planning to upgrade or replace your existing lens, please contact us for technical confirmation. Our engineers can provide guidance for installation, focusing, and calibration to help you achieve the best image performance.


More Thermal Camera Lenses (4mm–45mm Range)
High-quality infrared lenses for 640×512 thermal imaging cameras. Available focal lengths: 4mm, 6.8mm, 9mm, 15mm, 25mm, 35mm, and 45mm, suitable for a wide range of imaging and detection needs.
Product Overview
Our interchangeable thermal camera lenses are designed for professional infrared imaging systems. Each lens is made from premium germanium material with a durable anti-reflection (AR) coating to ensure high transmittance in the 8–14μm LWIR band.
These lenses offer sharp thermal images, reliable mechanical performance, and flexible field-of-view options for multiple applications.
Available Focal Lengths
Choose the right lens for your thermal imaging core:
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4mm – Ultra wide-angle, close-range or drone mapping use
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6.8mm / 9mm – Medium-wide, suitable for firefighting or inspection
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15mm / 25mm – Balanced FOV for security and industrial monitoring
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35mm / 45mm – Long-range observation and perimeter defense
Each lens provides a unique balance of field of view and detection distance, making it easy to adapt to your project’s needs.
Key Features
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Focal lengths: 4mm / 6.8mm / 9mm / 15mm / 25mm / 35mm / 45mm
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Material: High-transmission Germanium (Ge)
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Coating: AR coating for LWIR (8–14μm)
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Mount type: M34, M45, or custom thread options
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Precision CNC-machined metal housing
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Stable optical alignment and focus retention
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Wide operating temperature range
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Long service life and excellent environmental resistance
Compatibility
Compatible with most 640×512 thermal cores, including:
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FLIR Boson series
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iRay / InfiRay modules
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Guide, Hikvision, and other OEM cores
Before replacement, please confirm:
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The mount interface type (M34 / M45 / custom)
-
The detector’s pixel pitch (12μm / 17μm)
-
Whether your camera is radiometric (temperature measuring) or non-radiometric (imaging only)
For non-radiometric versions, the lens can be directly replaced after manual focus.
For radiometric versions, recalibration is required to maintain temperature accuracy.
Applications
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UAV and drone thermal cameras
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Firefighting and rescue monitoring
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Industrial equipment inspection
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Building diagnostics and energy audits
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Public security and surveillance
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Night vision and defense systems
Why Choose Our Lenses
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Full range from wide to telephoto options
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Excellent infrared transmission and clarity
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Precision focus and alignment
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Factory-tested for mechanical and optical stability
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Professional technical support for selection and installation
FAQ
Q1: Can I replace the lens by myself?
Yes, if your camera uses a compatible mount and is a non-radiometric model. Manual focusing may be required after replacement.
Q2: Will changing the lens affect temperature measurement?
For radiometric thermal cameras, changing the lens requires recalibration to maintain accurate temperature readings.
Q3: Do you provide custom lens solutions?
Yes, customized focal lengths and mount types can be provided according to your application needs.



iVcan.com –
I recently upgraded my 640×512 thermal camera with the 4mm wide-angle infrared lens, and the difference is remarkable. The image clarity is excellent, even in low-light and foggy conditions, and the wide field of view allows me to capture more of the scene without repositioning the camera constantly. Installation was straightforward, and the lens feels solid and precisely machined. It’s perfect for drone mapping, industrial inspections, and security monitoring. The thermal details are sharp, and I’m very impressed with the overall quality and performance. Highly recommended for anyone needing reliable, professional-grade thermal imaging optics.