For this exercise I took a couple of shots through the hollow of a ladder rung looking out into my garden, with the deliberate intention of producing something more abstract than representational. The first was taken with the camera set to Aperture Priority, 18-135mm lens set at 56mm (I did not want the field of view to get too wide), f/5.6 to keep the depth of field shallow from the outset, ISO 100, shutter speed 1/160s. Only the end of the rung and the very front edge of the upright are in focus. The background, the body of a glazed door and the garden beyond are undistinguished blurs. The second was taken with exactly the same settings but focused to infinity. Shutter speed this time was 1/200s. Now only the slivers of garden are in focus, the edges of the door are soft and the ladder so blurred as to be unidentifiable. I had thought that there might be a tiny rectangle of garden in focus in the middle of the hollow rung but there was so much internal reflection and distortion with the rung that this small area is also out of focus.
From a visual point of view the first image is clearly more interesting, or at least more comfortable on the eye. The second is much harder to read and understand. From a compositional point of view the first image has a clear subject and focal point. Even if it is not immediately clear what you are looking at it is at least obvious that you are looking at “something”. It is much less obvious what the subject is in the second image, and what is clearly discernible is not much to hold your attention, let alone interest. The picture becomes an odd assortment of thin verticals with an indefinable blob in the middle.