A 19mm uncooled LWIR lens can be a suitable choice when a thermal system needs a defined focal length, but focal length alone does not confirm that the lens will work with a detector or provide the desired field of view (FOV). Buyers should verify the detector’s active area, pixel pitch, mounting interface, lens image circle, spectral range, and optical parameters such as f-number and back focal distance. At Hope-Wish, we recommend evaluating these details together before requesting a quotation or approving a design.
Click here to get more.
This guide is for OEMs, system integrators, and procurement teams evaluating a 19mm uncooled long-wave infrared (LWIR) lens for a thermal camera or security and protection system. It is intended to help buyers prepare a practical specification and identify questions to resolve with a lens supplier. It does not replace optical verification against the exact detector and camera design.
“19mm” describes the lens’s nominal focal length, while “uncooled LWIR” describes the intended thermal-imaging application and detector category. LWIR systems commonly operate in the 8–14 μm spectral region, but buyers should confirm the required operating band and the lens transmission specification rather than assume that every lens covers the same range. The lens collects and focuses incoming infrared radiation onto the detector, forming the thermal image used by the camera system.
Focal length affects image scale and field of view in combination with the detector’s active dimensions. For the same detector, a longer focal length generally produces a narrower field of view than a shorter one. A 19mm lens may therefore suit applications that need more scene detail at a given distance, but the appropriate choice depends on the target, working distance, and system requirements.
The detector’s active area is the portion of the sensor that records the image. The lens must produce an image circle that covers this area; otherwise, the system may show vignetting or fail to use the full detector. Check sensor width and height, not only the detector’s pixel count or package size.
Pixel pitch is the center-to-center spacing between detector pixels, and it affects how the optical image is sampled. For example, with a 19mm focal length and 12 μm pixel pitch, the approximate angular sampling per pixel is 0.63 mrad, calculated as pixel pitch divided by focal length. This is a geometric estimate, not a guarantee of image detail, which also depends on lens performance, detector characteristics, focus, and operating conditions.
Resolution and pixel pitch should be reviewed together with the lens specification. A detector with a higher pixel count does not automatically deliver greater usable detail if the lens cannot support the intended image quality across the sensor. Ask the supplier which detector format and pixel pitch the proposed lens configuration is designed to support.
Confirm the lens mount type, thread or interface dimensions, and the camera housing constraints. Also check back focal distance, focus adjustment, and any required spacing between the lens and detector. A lens that appears to fit mechanically may still be unsuitable if its optical position cannot be aligned with the camera assembly.
For a rectilinear lens, an approximate horizontal FOV can be calculated as 2 × arctan(sensor width ÷ (2 × focal length)); the vertical calculation uses sensor height. This shows why a 19mm focal length does not provide one universal FOV: the detector’s active dimensions are part of the calculation. The lens design and any system-specific optical effects may also influence the final result.
Hope-Wish contains other products and information you need, so please check it out.
As an illustrative calculation, a detector with a 7.68mm active width and a 19mm focal length gives an approximate horizontal FOV of 22.8°. This example assumes the stated active width and focal length and should not be treated as a specification for a particular Hope-Wish lens or camera. To assess a real project, use the detector’s actual active dimensions and confirm the result with the lens supplier.
LWIR lens designs may use materials such as germanium or infrared-transmitting chalcogenide glass, depending on the optical design and product requirements. Material choice can affect transmission, weight, durability, manufacturability, and cost, so it should be evaluated against the complete application rather than as a standalone quality indicator. Confirm the spectral band and coating details in the supplier’s specification for the exact configuration.
| Specification | Why It Matters | Buyer Check |
|---|---|---|
| Focal length | Influences image scale and FOV with the chosen detector. | Confirm that 19mm suits the target distance and coverage. |
| F-number | Relates to the lens’s light-gathering geometry and system design. | Match the specified value to camera and image-quality requirements. |
| Image circle | Determines whether the lens covers the detector’s active area. | Compare against the detector’s width and height. |
| Mount and back focal distance | Affect assembly fit and optical alignment. | Verify against the camera housing and detector position. |
| Spectral transmission | Indicates the wavelength range the lens is designed to transmit. | Request the documented band and coating information. |
A 19mm lens may be considered for perimeter security, industrial monitoring, or other thermal imaging tasks where the required balance of scene coverage and target detail fits the system. The right field of view depends on the target size, detection distance, camera placement, and whether the system prioritizes a broad scene or a more focused view. Define those requirements before comparing lens options.
For a fixed installation, buyers should also consider focus behavior, housing space, environmental exposure, and whether the camera must operate across changing temperatures. For mobile or compact equipment, size, mass, and mechanical stability may be important constraints. These factors do not establish that a particular lens is suitable; they help define what the supplier needs to assess.
Pricing for a 19mm LWIR lens can depend on the optical configuration, materials, coating, mounting requirements, quantity, and any customization. Minimum order quantities and lead times are likewise supplier- and project-dependent, so buyers should confirm them for the specific request rather than rely on a general estimate. For an efficient quotation, include forecast quantity, target delivery schedule, application, detector details, and any packaging or documentation requirements.
Ask the supplier for a product specification that identifies the focal length, supported detector format or image circle, f-number, spectral range, mount, and relevant optical and mechanical dimensions. Clarify whether the quoted item is a standard configuration or requires customization, and request the applicable inspection or acceptance information for your project. If a parameter is not documented, treat it as an open point to resolve before design approval.
At Hope-Wish, we can review the detector and application information you provide and discuss whether a 19mm uncooled LWIR lens configuration is appropriate for your requirements. We recommend sharing the sensor model, active dimensions, pixel pitch, desired FOV, mounting constraints, and expected order quantity. This gives our team a clearer basis for discussing compatibility, customization options, and quotation details without assuming a fit from focal length alone.
A 19mm uncooled LWIR lens is compatible only when its optical coverage, detector characteristics, mechanical interface, and system requirements align. Its field of view must be calculated from both focal length and detector active dimensions, then checked against the intended scene and the lens specification. The most reliable next step is to prepare a detector and application brief and have the proposed configuration reviewed before ordering.
Contact Hope-Wish with your detector model, active area, pixel pitch, target distance, required coverage, and estimated quantity to begin a focused selection and quotation discussion. If any specifications are still undecided, identify them as provisional so the supplier can distinguish confirmed requirements from assumptions. This helps reduce avoidable compatibility issues during system integration.
If you want to learn more, please visit our website 19mm Uncooled LWIR Lenses.