On the NCN forum we became curious about the wide open performance of the Vivitar 70-150 1:3.8 wich at least 2 of us use. Both a Kiron made version. After he went out and shot wide open he was a bit disappointed, but seems to be turning a bit after more testing. So i tried again today and was surprised.
Sure @ f8 it is way sharper but images are good after a bit of extra sharpening, but not that much after all.
Above is one of today! Judge for yourself.
Shot Info: iso 400 - f3.8 - 1/320 - 150mm