This adapter was my latest in my quest to find an FD to E adapter that will truly focus to infinity. I have tried lots of different brands. All of them will focus to infinity with a lens 50mm or longer. Wide angle lenses are another story. I finally found one that worked with most lenses in the Fotasy PRO series. They are fine down to a 20mm lens. A 17mm lens is an issue for them. I bought several and some would just barely do it and some would just barely miss. I want one adapter per lens so I needed several. I wanted to KNOW it was right, so I tried this one.Let me start by saying the K&F adapter is the best built adapter I've tried. It fits the lens and camera perfectly. The aperture control is super smooth. When on a lens it feels as if it's an integral part of the lens itself. But can it hit infinity? The answer is yes, but with a slight problem. It goes past infinity by quite a bit. When the lens is properly focused on an object about 100ft away (which for the 17mm is pretty much infinity) the distance scale on the lens shows a touch over 10ft. It's not a lens issue as I have two of them they both show the same result. This could make using hyperfocal techniques difficult. But, it can focus to infinity so it's the one that is mounted on a 17mm at the moment.In conclusion, if you don't use the distance scale on your lens for anything this is the adapter to buy. It's decently priced, very well made, and will hit infinity with any lens. If you set your focus by using hyperfocal distance, then get the Fotasy Pro for anything 20mm or more.