How to Control Depth of Field

Photography Tips

Have you ever snapped a portrait then realized the background is too busy? What if you really like the colors, but just need it to be a bit blurrier to bring the focus to your subject? In this video, photographer Terry White explains exactly how to control your depth of field to blur the background while keeping your subject in focus:

What is Depth of Field?

Depth of field refers to “the distance between the nearest and farthest objects in a scene that appear acceptably sharp in the image.” You can control the size of the area in focus in a number of ways.

Two Ways to Control Depth of Field

White says there are two main ways to control your depth of field.

1. Subject Placement

The first is to physically move your subject further from the background, automatically changing the depth of field. The further your model is from the background, the less in-focus the background will appear.

2. Aperture

The second option is to change your camera settings:

“However, if you’re in a tight space, a tight, small studio, and you don’t have the liberty of moving the subject that far off the background, then you really need to control it with your f-stop.”

How Aperture Size Affects Depth of Field

These four photos show how aperture size affects background blur.

White snapped four shots of his model using the Wescott Skylux LED Light and the Modern Vintage Backgrounds–each at a different f-stop. Most kit lenses have an aperture range of f/5.6 to f/3.5, so he took one photo at each of those. He also snapped a shot at f/2.8 and another at f/1.4 to demonstrate the f-stop capabilities of higher-end lenses.

The pattern remains in focus at f/5.6 and starts to slightly blur at f/3.5. However, White says the focus hits the “sweet spot” at f/2.8 and the background continues to dissipate at f/1.4. He notes that this is a good reason to spend a bit more money on a higher-quality lens:

“Not only do you get to shoot in lower light conditions, but you also get to control your depth of field better.”

Keep in mind, there is an inverse relationship between the f-stop and the shutter speed. To maintain the correct exposure, as you lower the f-stop, you need to increase your shutter speed. You can read a full explanation about the relationship here.