one of my photography teachers told us a story that I thought was a bit of overkill as far as exposure goes. He said he was taking an interior of a church so it was a long exposure, over half an hour, so they worked out the L & D curve or such and worked out the exposure from that. Wouldn't it be quicker to look at the reciprocity of the film and go from there. Being a student I've been working with a few pro photographers and most just take a reading, shoot and bracket, with regard to v high or v low tones. Hell, some pros said after school no one cares about sensitometry ! He is a ditherey old guy but we just can't work out why go so far.......