How do humans perceive three dimensions? The first thing that comes to mind is we have two eyes. We see slightly different images in each and then our brains munge them together and we get 3D in our minds. And the only way a photographer can create that same thing is with special cameras and weird glasses.

But there are lots of other ways our minds perceive three dimensions, most of which can be seen in a 2D photograph.

Close Things Block Far Things

This one may seem obvious, but it is worth mentioning. If something is closer to the camera, it may block something further away. Something in the foreground can block the subject. The subject can block the background.

Things Closer To The Camera Are Bigger

And conversely things further away are smaller. So big things are thought to be closer to us, which makes for some cool perspective tricks, but something you can to your advantage. Using the Hollis rifle image above, the barrel of the gun is very big, way bigger than in reality. That is because it is closer to the camera. Since our brains know she’s not holding a howitzer, we know it is closer to the camera. Actually very close.

Keep the bigger closer, smaller further thing in your head when model parts are coming at you in a photograph. If you’ve got a subject/model that might be a little big in the middle, don’t put her stomach close to the camera. This is the big chicks love the MySpace angle, the big parts are far away and the face is up close.

Depth of Field Tells Us Something

If something is fuzzy and doesn’t block the subject, the eye thinks – rightly – it is further away than the subject. If it is fuzzy and blocks the subject, then it is in front of the subject. This is caused by Depth of Field. Only somethings are in focus. Where we focus our eyes. Our brain uses this information to map the location of things in our view.

Our brains are amazing things and really use all of these things and more in combination to create three dimensional maps in our head. You need to be conscious of them and use them to your advantage.

Do you have images that look particularly 3D you’d like to share? Post them in the forum.