Now, the picture looks like this to me: you're trying to shoot the sea, the shore, and the little dark stone on the sand using the rule of thirds so far so good; then, dear Rebecca makes a joke and interferes with her dad's aim jumping suddenly to the front of the camera with a sweetly vicious and self-confident smile... The off-centered nature of the composition, the movement of her hair all tell me these things, and I think that this is a very nice candid portrait... BTW, PhrankPower's comment made me laugh so much, the one starting with "10 years from now...". Regards to you all... :-)