There are two major types of cameras that can be used for estimating the health of plants: multispectral and modified cameras. Pix4Dmapper can process both types of imagery, the choice of filter/band depends entirely on the intent.
Multispectral, narrow band cameras
These cameras are designed for fidelity in order to be as accurate as possible when measuring the reflectance of objects. Multispectral cameras can come with sun irradiance sensors and/or a calibration target to properly estimate the incoming sunlight irradiance effect and compute absolute reflectance. For more information: Radiometric calibration target, Radiometric corrections.
Such cameras include Sequoia, Multispec 4C and Micasense RedEdge. For more information: How to process Sequoia imagery.
Modified standard cameras
By carefully changing the filters of a normal camera, it is possible to get wide band infrared measurements. However, it is critical to follow a certain workflow to obtain somewhat accurate relative measurements. Many companies offer to either modify cameras or sell already modified cameras. For more information: Camera Requirements for Precision Agriculture, How to set the band weights for modified cameras (NIR,R,G and NIR,G,B).