step-down ring and vignetting on crop sensor
I have 58mm CP and ND filters for an FX 50mm lens on a crop sensor Nikon camera. An FX 85mm lens takes 67mm filters. I could use 58mm filters with a step down ring without vignetting because 67/1.5 = 44 < 58. In fact, I could use the 58mm filters with a step down ring on an FX lens that takes 77mm filters because 77/1.5 = 51 < 58. Is that right?