If you have to have a 180mm lens that covers 8x10, the Zeiss Dagor f/9 is a good choice. Not easy to find, but it has an image circle of 15 1/2 inches. Tiny and sharp. My favorite 810 wide angle lens. The regular Dagor 240mm f/6.8 lens has an image circle of 14 inches. Yes, a Protar v 181mm will cover slightly more (16 inches of image circle) than Zeiss Dagor f/9, but it is not easy to focus.