Graininess can be caused by using high ISO's and also under exposing images. We do like to raise ISO levels to use natural light as much as possible and sometimes this is the cause of grain in our images. Other times it can be an problem with under-exposure, where the image itself was exposed too dark and has been lifted in brightness in post production which casuses the grain. This can happen from time to time when shooting more rapid fire, but generally we do our utmost to correctly expose all our images and keep grain to a minimum.
We also plan to integrate new cameras that perform better under lower light and with have less grain or noise. So this will hopefully help you guys see everything in perfect crisp detail. We plan to be shooting more with new cameras in February.
Okay hope that explains it from a production point of view.