im a photography student, we use 4x5, trust me..... trust me... this happens to everyone. I have watched people do 30 minute exposures only to realize the darkslide was never pulled. I have gotten blank sheets back from the lab on a few occasions as well even though I thought Id shot everything. People also worst of all forget to factor bellows when doing macro, and in that case you end up 4 - 6 stops under, not mentioning reciprocity which they also usually forget so add a few more stops. The list goes on. It took me 5 shoots to get a sharp negative, dont ask why cause I dont know, was thinking my lens or something was a dud then one day bam, started getting tack sharp results and realised why 4x5 is so good, even in a bad epson scanner the detail is amazing.