I just got a ND6 n 10 internal type of filter for mirrorless body. The fisheye could not be focus, I check and the limit is 14mm. For those getting this type of filter, beware of this issue. Maybe the filter or my sensor got water marks on it, did a long exposure and whole skyline got so many. Anyway, it's a good investment for me, lazy to do the change of the filter on the lens.