If it is a portrait shoot, then to me the whole process is highly interactive, because, when it comes down to basics, I want to capture the sitters vital spark and I want their engagement. I will be shooting for a printed result, hence my use of film. Setting up and losing the first few shots to digital is no loss to me in this context (in film only days I would always right off the first few frames anyway; might have well have used an empty camera). By using digital as a setup check, the people being photographed get a direct feedback re. what I am doing and they get a hint at what the end result might be. The benefit is that they will also relax and engage. To me, this is worth a few lost frames before I commit to film. Another important benefit is that it is fun! As far as exposure is concerned, all I can say is that for all practical purposes my cameras (digital and otherwise) and light meter broadly agree.