Even with focus peaking, I found that focus accuracy is still a bit hit and miss, so it is best to stop down a bit. The adapter is a cheap one which I was given a while back and has not been produced to the tightest tolerances. Consequently, the maker has erred on the side of caution and the adapter is a fraction too short, which means that the lens focuses past infinity, but that is definitely better than not being able to focus to infinity.
