There appears to be no ISO value in the metadata for the multiSPEC 4C. Therefore how is the irradiance (and subsequent reflectance) calculated? Albedo, FNumber, exposure and downwell irradiance are present.
The ISO is not tagged because it cannot be changed. It is the same as during the factory calibration, so it is already taken into account in the sensitivity of the camera.
Thanks for the reply Manuel
Therefore the calculation for sensor irradiance would be?
To get the general formula of the irradiance computation, please contact directly the camera manufacturer, in this case Airinov.