1 pointFor Canon shooters using a WACP-1, the back button focus should be used. The lens behind the WACP-1 is an old, clunky Canon lens (28-70mm f3.5-4.5) which is not that fast. I've often gotten out of focus shots when using only the shutter lever, where it couldn't focus fast enough before the shutter opened.
1 pointSold. Thanks. Glad to see it getting more use in the future!