I used the Nikon camera with 400 Delta. I actually rated that at 300 as previous testing with a densitometer suggested 320, but the N75 can only adjust film speed by half stops via exposure compensation. The Acros was the first roll of this film I had tried. I had bought it due to recomendations regarding its good reciprocity characteristics. I do a lot of night and low-light work. I then needed to use it when I had nothing else in stock, but a 400 speed film was required. I'll finish it at that speed and develop to the Massive Dev recomendation to see how it looks. I've stocked-up on plenty of Tri-X today to avoid this sort of dilema in future! I prefer to use 400 with the built-in flash as it seems to give better results. Alex