Find a subject in front of a background with depth. Take a close viewpoint and zoom in; you’ll need to be aware of the minimum focusing distance of your lens. Focus on the subject and take a single shot. Then, without changing the focal length, set the focus to infinity and take a second shot.
These images were taken with a Canon EOS 5D mark IV full frame camera with a 24-70mm lens, it was set to aperture priority, F/3.2 and ISO 200.
For the first image I focused on the railings, when you take a close viewpoint and zoom in you achieve a very shallow depth of field. For the second image, and without changing any of the camera settings, I focused through the railings to infinity, this creates a very deep depth of field.
Evaluating the two shots side by side, you can see how a focus point can make a significant difference to an image. In the first image your eyes are drawn straight to the railings, and as the shallow depth of field blurs the background your eyes have nowhere else to go other than back to the railings. The second image is looking through and beyond the railings, however your eye are constantly being drawn back to the railings almost as if they are in the way. I do not think there is a right or wrong focus point, but I have to agree that the focus point in the foreground is generally more pleasing.
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