Exakta's had several types of aperature control, manual, pre set, semi auto and automatic. This appears to be the simplest type. Many lens makers made lenses to fit Exakta and Schneider was likely the best. Enna Werke was a mid range lens supplier so it is a common, simple lens that would probably perform OK if it is in good shape. I like Exakta's and have a few but never got comfortable using them. That said the 58mm f2.0 Biotar is one of my favorite classic lenses. Joe
