Used Velvia 50 and 100F. Used to shot with Provia 100F or NPS 160 with my Medium Format camera. NPS 160 is still my first choice for portrait. Velvia 50 is more detailed in 1 and 2 stops over and under exposition. (zone III, IV, VI and VII)where Velvia 100 is a little bit more confused. The grain is absolutely equal to the Velvia 50 in common situations. It's a nice emulsion if you need more sensibility than 50 iso.