With this first exercise I found this skateboarding park that had the depth to demonstrate focusing using a set aperture. I chose the following pics to demonstrate the use of focus to tell a story but in-between exposures i checked the highlight and histograms on the camera and felt that the aperture should be stopped down 1 stop to compensate for the shutter speed, as that was set to the maximum of 8000/s. It was a very bright day.
I feel that the 2 exposures still manage to demonstrate the use of focus to change the meaning of a picture by directing the eye to a different point in the frame. In the first frame where the boy on the scooter occupies the top of the frame, you get a sense of being directed to the boy entering the skate park by the curves of the skate pikes. Then you are drawn to the less sharp skull graffiti which seems to add jeopardy to the image.
On the second image, the focus is sharp on the skull graffiti giving the image a sense of doom looming for the unsuspecting boy.
The focus changes the meaning of the picture by highlighting the main subject or clue to the intended meaning of the picture.
I prefer the second image as there seems to be a nice tension between the skull and the out of focus boy on the scooter. The first image works well but the focus on the boy also brings the graffiti of the girl, to the left, into focus and challenges for attention. Although, I think the boy on the scooter wins the focus war, the second image has no such conflict.