After many months of frustration with this lens, I finally decided to try zone focusing or if not successful, hyperfocal focusing. As it turned out, zone did not work as yet. But hyperfocal seems to be giving some joy. The trick for me at least is to find out where infinity is (it is generally not where it should be ). Mark it or remember it's position. Keep an aperture of f8 or so and then for everything beyond 20 feet or is mostly on focus. A slight adjustment gives better results. At larger apertures, o am still struggling.