Recently I have been looking for some old style NIKON F AI MF lenses across the internet. I got this one. It is a discount, costs next to nothing. Of course it’s not only about the money, but about the performance you can get from it. It’s a NIKON F mount, AI-S lens. AI-S has a depressed notch on the mounting ring. AI in general has secondary f-stops markings but more importantly has light-meter coupling. Compatibility I can mount it on my NIKON D200 camera and get both focus confirmation dot in viewfinder as well as proper metering thanks to