Choosing a bandpass filter for NIR imaging
Near-infrared is the workhorse of machine vision — but only if you pass the right band and block everything else. Here is how to pick.
Near-infrared (NIR) light cuts through ambient glare, sees past surface coatings, and pairs with cheap, powerful LEDs. That makes it the default for code reading, web inspection, and presence detection. The catch: your sensor is just as sensitive to every other wavelength in the room.
Pass the band, block the rest
A bandpass filter passes a narrow window of light and rejects the rest. Hover the curve below to read transmission nm-by-nm for three common NIR bandpasses — notice how each one isolates its LED while staying dark everywhere else.
Match the filter to your illumination: an 850 nm LED wants an 850 nm bandpass. The closer the match, the more signal you keep and the more ambient you reject.
BP850Near-IR Bandpass Filter · 850 nmView filter →It passed in your lab. Will it pass on their floor? A filter is the cheapest insurance in your bill of materials.— MidOpt
Watch the angle
Interference bandpass filters shift toward shorter wavelengths at steep angles of incidence — a real problem with short focal-length lenses. StablEDGE® minimizes that shift so the passband stays put across the field of view.
Compare any two curves
Overlay transmission curves for any MidOpt filters and read values nm-by-nm.
Still unsure? Start from your light source and let the LED-to-Filter Guide pair it for you — or send us your application and we will recommend a part.