ed eaton this might be your photoworks answer

c cast photons though this is normally refeered to as cast rays
g gather photons this is normally referred to as gather rays

the two are linked to lighting conditions

could be something they have done to quantify whats going on with
photoworks when using the the mental images part of the renderer

its called emiot photons and final gather in the fully blown mental
ray renderer ive seen this before when using mr standalone

dont qoute me though its probably normal and i doubt you will find any
contol on the photon emission or the gather as they have probably
linked the two within certain boundaries to give you a good lighting
result instead of getting it horribly wrong and over or under exposing
the scene

this is all to easily done in mental ray if you dont quite understand
whats going on so my guess is theyve nade it idiot proof in photoworks
and taken the controls out to some degree