Over the years I have tried this many times but it was not right for me, the lens I use now has an FN button on it so I programmed it for focus,not good light today but after trying it ime going to stick with it for more testing.
P1010161 by electric.mike, on Flickr
P1010144 by electric.mike, on Flickr
P1010161 by electric.mike, on Flickr
P1010144 by electric.mike, on Flickr