I wonder if you'll be surprised the way I was, looking at this shot. The 1st one is a 100% crop and the other 2 include the focus points (from DPP) and a DOF calculator with the specs, one using 0.035mm as the CoC and one using the Pixel Pitch of the 40D.


I wanted Dinara Safina's face but got the back wall instead. That wall is approx. 10 feet behind her, yet the shot is close to being acceptably sharp. Of course definitions of "acceptably" vary, but regardless, wouldn't you think her face would be way out of focus, considering how far away the focus point is? (disregard the motion blur in her arms, hands, racket - it was intentional)


I ask because I have shots where I really nailed the focus, right on the player's face, and the difference, while obvious, isn't exactly "night n day." I'm surprised. I thought missing focus by 10 feet, with a DOF of (at most) 4 feet would show a very blurry subject.


[from the U.S. Open, Thursday 9/3/09, Louis Armstrong Stadium - 40D 70-200 2.8 IS, 1/640 @ f/4.0 ISO 100 hand held. Shooting distance approx. 40 feet, focal length 145mm.]


[img]/cfs-file.ashx/__key/CommunityServer.Components.UserFiles/00.00.00.29.05/DOF_5F00_100prcnt_5F00_crp.JPG[/img]


[img]/cfs-file.ashx/__key/CommunityServer.Components.UserFiles/00.00.00.29.05/DOF_5F00_.35CoC.jpg[/img]


[img]/cfs-file.ashx/__key/CommunityServer.Components.UserFiles/00.00.00.29.05/DOF_5F00_CoC_5F00_PxlPtch.JPG[/img]