Resources/CAMCUDA Wiki/F-number
Optics & field of view

F-number

Lens aperture ratio

CAMCUDA WIKIUpdated 29 October 20262 min read

The ratio of focal length to entrance-pupil diameter.

What it means

The lens F-number, written for example as F/1.0, relates focal length to the effective entrance aperture. It affects the amount of radiation reaching the detector.

Lens aperture is one reason thermal-sensitivity specifications must be compared under equivalent conditions. An NETD value quoted with one lens is not automatically the performance of every lens option.

In practice

Integration note

Read the F-number and other test conditions next to an NETD value before comparing modules.

Try it with your configuration

Open the thermal imaging calculator ↗ to explore field of view and geometric scene coverage.

NETDFocal lengthSpectral range

Related product resources

SuperMini-640 ↗Ultra-light core640 × 512 · 8 µmAirTiny2 ↗13 mm core256 × 192 · 12 µm · ≤25 Hz

Continue with an Engineering Guide ↗

Sources & further reading

  1. SuperMini 640 Product Specifications V1.0.0.pdf
  2. SuperMini 640T Product Specifications V1.0.0.pdf
  3. AirTiny2 Product Specifications V1.0.0.pdf
  4. FLIR OEM: Lens F-number and NEdT

Concept explanations are general. Use the matching product, lens, interface board and firmware documentation for the delivered configuration.

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