If he can explain aperture, to give me a memorable word picture, I'm golden. (Of course, he's more of a Golden than I will ever be, thanks to his canine heritage. But I digress.) Take it away, Polo!
In back yard, I focus on Squirrel. No concern about what is behind, around Squirrel. Squirrel, my mortal enemy, my wide-eyed concentration. I have big, big eyes for Squirrel. Background no matter, let it blur so that Squirrel is only subject.
But if Crow lands on fence, I must narrow eyes to watch Crow and Squirrel. Crow my mortal-est mortal enemy. I might someday catch Squirrel; but Crow flies, sneaks up, does mean things. I make eyes small to watch near Squirrel and farther Crow. My expression with small eyes is inscrutable. Do not let Crow see my thinking.
Okay, so that one word -- inscrutable -- gives me a strong mental image. When Polo has more than one subject to watch, he squints. Sure, in his case, it's a psychological game, but the practical application is that making the aperture smaller will increase the depth of field so that he can focus on both the near and far critters of malice.
|f/5.6 (largest available aperture)|
|f/36 (smallest available aperture)|
|marshmallows at f/5.6|
|marshmallow visual pun at f/36|
Must be inscrutable, watch both Mortal Enemies at same time. And take nap.