Practical research · 2 October 2026
Thermal Camera Accuracy vs Sensitivity: What the Numbers Mean
A thermal camera can reveal a small temperature difference without measuring the absolute temperature to the same precision. Sensitivity, accuracy and image resolution describe different capabilities. Match the specification to the decision you need to make instead of choosing the smallest number on the box.
Sensitivity is about distinguishing differences
Thermal sensitivity, often described by NETD, concerns the camera’s ability to distinguish small thermal differences under specified test conditions. FLIR discusses this separately from absolute temperature accuracy. A low sensitivity figure is not a promise that every temperature displayed is correct to that fraction of a degree.
For a buying comparison, copy the complete specification and its conditions. Ask whether two cameras’ figures were obtained using comparable conditions. Do not compare a sensitivity value expressed in millikelvin directly with an accuracy allowance expressed in degrees or percent.
Source: FLIR: thermal sensitivity
Accuracy needs its conditions
An accuracy specification describes an allowance under stated conditions. FLIR explains that measurement setup also affects the result, including emissivity and target size. A calibrated camera does not correct a poor viewing angle, reflections or a target too small for the measurement area.
Suppose two cameras both display 40.0°C. The extra decimal does not establish tenth-degree accuracy. Ask what uncertainty applies at that temperature, at the intended distance and on the actual surface. This example is explanatory, not a test of either camera.
Source: FLIR: accuracy and uncertainty
Resolution answers another question
Image resolution describes the detector’s spatial sampling. More pixels can help show detail, but the target must still occupy an adequate measurement area and be in focus. A sharp visible-light overlay can make a thermal image easier to interpret without adding thermal detector pixels.
Record native infrared resolution separately from visible-camera resolution and software-enhanced output. For electronics, inspect minimum focus distance and a real image of a similar-size component. For building work, consider the field of view and how much area you need to survey.
Calibration is a service question
FLIR describes calibration certificates as documenting the calibration process and associated measurement information. Ask what service is available for the exact model and whether a certificate is supplied, optional or required for your work.
A shutter correction or camera self-adjustment during use should not be assumed to replace a traceable calibration service. Follow the manufacturer’s interval and your organization’s measurement requirements. Keep service costs separate from the purchase price.
Source: FLIR: camera calibration
Use a specification comparison that matches the job
This table is a buying checklist, not a ranking. A cheaper camera may be adequate for finding a pattern while a documented measurement task may require a different instrument and training.
| Your task | Prioritize |
|---|---|
| Find broad warm/cool patterns | Field of view, sensitivity and usable image |
| Inspect small circuit components | Native IR resolution, focus and target size |
| Report a temperature | Accuracy conditions, calibration and setup |
| Repeat an inspection later | Saved radiometric data and consistent method |
| Work across phones | Exact connector, app and device compatibility |
What to ask before buying
Ask the seller for the manual and a sample file from the exact camera. Confirm whether exported files retain measurement information or only a colored image. Check whether the software needed to read them has additional costs.
Our existing camera comparisons remain useful for model selection, but no model can remove the need to understand the surface and measurement conditions. For safety-critical electrical or industrial decisions, use a qualified inspection process rather than treating a consumer camera as a standalone verdict.