The problem is simple, i used Pol filter that day for all films including Velvia 50, the shots of Velvia 100 on GSW6x9 without any filter, so maybe i forgot to compensate for filter stops, but that day i was shooting 5 rolls, 4 colors all with filters, only the Velvia 50 was the dense roll, when i use this film without filter it is shinning and vivid nice colors, i need to use this film a lot with and without filters to understand it and watch my exposure each time, i don't feel sad at all about the roll because it was a test day, and i don't have an issue if the camera has a built-in meter or not, i was metering with a digital camera and a Sekonic light meter, i don't limit myself with only film camera without anything and then no internal light meter then i have to guess or waste the roll if wrong exposure, if i am a photographer then i should be serious and advanced, not just go out and shoot without watching the exposure or using light meter, not all cameras i can have internal meters, what i can do if there is no built-in light meter in the camera i carry??? I feel exposing the film whatever it is is not a big problem, sometimes there is a time very important that i want to be sure i got the film exposure spot on, but another time for test only i get the best result, mistakes can happen, and your mistake is not that bad at all, and honestly speaking, with your roll i can recover the frames way better than my so dense Velvia 50, my scanner doing a great job for me these days.