HI,

Please, How to calibrate phantom 4 multispectral camera in field? and posterior, how to calibrate on Pix4Dmapper, for example I have:
No correction
Camera only
camera and sun irradiance
etc
Thanks

Hi,

There are several threads about it in the phantom 4 Multispectral section of the forum.  

There is also the Phantom 4 Multispectral manual that explains how to do it.  
https://dl.djicdn.com/downloads/p4-multispectral/20200717/P4_Multispectral_Image_Processing_Guide_EN.pdf

And there is Agisoft Metashape which does the operation automatically based on the instructions in the manual.  
https://agisoft.freshdesk.com/support/solutions/articles/31000159853-dji-phantom-4-multispectral-data-processing

From Pix4D we only have mystical answers, they claim that using a reflectance target solves all problems but it's not that simple.
https://community.pix4d.com/t/reflectance-by-phantom4-multispectral/13536

Watch out for the RedEdge band:
https://forum.dji.com/thread-285846-1-1.html

Pay attention to the angle of trajectory:
https://forum.dji.com/thread-231375-1-1.html