[Auracle]

If you have the camera focus on the person, they'll be in perfect focus. If you then have the camera focus on the ocean, it'll be in focus.

Our eyes work the same way. Of course, just like the camera's aperture can be set our pupils will be pretty contracted on a beach.

Of course, you should be able to tell the AI to generate it how you want - that's the goal, after all. Having at least a somewhat shallow depth of field by default makes sense though.