More work is needed to refine and improve hemispherical canopy photography as a technique.
This requires on-going monitoring of both reflected skylight and direct sunlight in the opening. Hemispherical photography and direct measurement techniques need to be further calibrated and compared. The importance of penumbral effects, reflections on leaves, and transmission through foliage needs to be assessed for particular sites. The importance of each source of error in the hemispherical photography technique must be evaluated, including problems arising during photograph acquisition, digitization, and analysis. The two greatest difficulties appear to be first, obtaining photographs with even sky lighting and no leaf reflections, and second, consistently choosing the same threshold to distinguish foliage from canopy openings.