Thermography is a formidable tool for board repair. A shorted component heats up before it fails, an overloaded trace becomes visible, a cold solder joint creates a visible thermal dead spot. All without disassembly or probing.
But the criteria that make a good building camera aren't the same as those for a good board-repair camera. And most buying guides mix them up.
IFOV is useless to you
IFOV describes what you can distinguish at a distance. It's decisive for observing an electrical panel from three meters away. In front of a board three centimeters away, it becomes almost meaningless.
What limits you is no longer the angle covered by a pixel, but the optics' ability to focus very close. Most cameras on the market have a minimum focus distance between 15 and 50 centimeters. At that distance, a 0402 package takes up a fraction of a pixel.
The macro lens: a baseline requirement
Without a macro lens, no camera in our catalog lets you work seriously on a board. It's an accessory, often sold around €100, that mounts in front of the optics and brings the working distance down to a few centimeters.
In our database of 101 devices, only twelve offer a macro lens, and half of those don't document a single one of its specs:
- HIKMICRO offers a documented macro lens for its B and Pocket series: 30 mm working distance, 100 µm spot size, 500 µm smallest measurable area. Its Eco series offers the same option but doesn't publish a single spec for it.
- Thermal Master documents its macro lens best on the P3: 8 mm working distance, capable of detecting a 1 mA current leak on a board. The P2 Pro's is 40 mm.
- Qianli designs devices that are natively macro rather than optional: from an 80 mm working distance on the Super IR Cam 2S Pro down to just 2 mm on the Mini S, built to mount on a repair microscope.
- InfiRay ships a magnetic macro lens with the P2 Pro, but publishes none of its specs.
- TOPDON, Seek, UNI-T, FLIR, Bosch, testo, Fluke, FOTRIC, Guide, and Klein Tools don't offer one for the models in our catalog.
The trade-off no one advertises
Here's the most useful piece of information in this article, and it only appears on the accessory's own datasheet, never on the camera's.
Mounted on a B series, the HIKMICRO macro lens degrades accuracy from ±2°C to ±3°C or ±3%, and caps the measurement range at 150°C.
For board repair, that's acceptable: you're looking for an abnormally hot component, not an absolute value to a tenth of a degree, and 150°C comfortably covers the temperatures you'll encounter. But you need to know it before buying, not discover it afterward.
Seeing a component isn't enough: you need to be able to measure it
This is the distinction retailer listings gloss over. Spot size indicates what the optics can resolve. The smallest measurable area, roughly five times larger, indicates the zone from which the reading is reliable.
With the HIKMICRO macro lens, you can see a 100 µm detail but you only get an accurate reading from 500 µm up. Translated into components: a 0402 package measures 1 × 0.5 mm, so it's measurable. A 0201, which measures 0.6 × 0.3 mm, is visible but its reading will be underestimated.
The other criteria that actually matter
Full radiometry. It determines whether every pixel of the recorded image retains its temperature value, letting you reopen an image and take measurements from it later. Without it, your image is just a colored photo. Check that the manufacturer says "radiometric JPEG" and not simply ".jpg".
The emissivity setting. On a board, you're dealing with bare copper, epoxy, plastic packages, and aluminum heat sinks all at once, with emissivities ranging from 0.05 to 0.95. Without a setting, your readings on metal surfaces are meaningless.
Frame rate. It matters here, unlike in building work. You power up the board and watch the temperature rise, which can be fast on a shorted component. At 9 Hz, you miss the transient.
The number of simultaneous cursors. Comparing several components on the same stage requires placing multiple measurement points at once.
What our ranking shows
Our comparator's "electronics repair" profile weights the macro lens at 40% of the optics family and the smallest measurable area at 25%, versus 5% for IFOV. The result flips the general ranking: HIKMICRO's B and Pocket series move to the front, and smartphone modules fall sharply behind, for lack of a documented macro lens.
One closing piece of advice you won't find on any datasheet: budget for the macro lens from the moment you buy. The real cost of a camera for this job is the sticker price plus about a hundred euros.
See the ranking for electronics repair.
All values cited come from manufacturer datasheets and the sources listed on each product page. No data is estimated.