ok I bought my Nikon 50mm 1.8 prime lens today. Had to buy it used because noone in town had a new one till monday and I want to shoot with it this weekend. I am curious about the aperture ring around the end nearest the camera body. The number 22 is in red and any time I Move the ring off that setting my camera won't function. Even in fully manual mode it just gives me a flashing error message in the window of F33. Can anyone tell me what this means? My sigma lens does the same thing.