Is middleground really the term for the thing between the foreground and the background? I don’t know, but it A) let me make a hobbit joke, which is cool, and B) explains where this part of the picture is well.
This is where we put the subject. There’s the stuff in front of the model – the foreground, and the stuff behind the model – the background. Where the model is is the middleground.
But is seems this creates a bunch of misconceptions about the middle area. Let’s break down the image of Hollis behind the vail.
Foreground, the vail. Middleground, Hollis’ face, specifically lips and eyes. Background, the window behind her.
Notice a couple of common misconceptions abused in this image.
Is the model in focus? Nope, the middleground is fuzzy. The foreground is in focus, as is the background.
Is the model halfway between the background and the foreground? Nope. Often the model is right behind the foreground. Sometimes really close. Sometimes she’s way far away, or right up against the background.
Don’t be afraid to play with where the model is in the 3D space of the image.