Depth of field or DOF refers to how much of your photo is in focus. Your depth of field is determine by the type of camera, your aperture, focal range, and your focusing distance. In this beginner tutorial we will explain depth of field and how manipulate it to achieve your desired look. For this tutorial we assume you already understand the basic photography concepts like aperture.
Understanding aperture and how it affects your depth of field is critical. A common mistake for people trying to shoot in low light situations is to open up their aperture (lower f/stop number). Shooting at f/2.8 will allow in twice as much light compared to f/4, but your depth of field decreases by about 30%. When taking photos of two people for example, that 30% shallower depth of field may result in one of the people being out of focus or blurry.
The distance to you subject also affects your depth of field. Let’s take the aperture example above and see what happens when you get further away from your subject. Let’s say you are shooting at f/4 but you want to shoot at a larger aperture to capture more light. Sure you can also adjust your ISO and shutter speed but we will ignore those for now.
Let’s assume you are 10 feet away from your subject. Shooting on a crop sensor camera, at f/4 and 55mm, at 10 feet will give you a depth of field or in focus area of 1.5 feet. Moving to an aperture of f/2.8 drops your depth of field to 1.07 feet. Now step back 2 feet from your subject and your depth of field increases to 1.54 feet. So this allowed you to get twice the amount of light into your camera and keep the same depth of field by stepping back two feet.
Now let’s use the example above and let’s say you want to fill the photo with your subject. At 55mm and 10 feet away they fill your frame, but they will not fill your frame when you step back 2 feet. They will appear smaller in your photo. You can always crop your photo later, but to fill your frame at the time of your photo you will need to adjust how much you are zooming. Now you are playing a balancing game. The more you zoom in the shallower your depth of field. Stepping back again increases your depth of field, but you will need to zoom in more as well.
Another factor on your depth so field is the crop factor of your sensor. Crop vs Full Frame shooting will vary your depth of field. Everything else being equal a full frame sensor will have a deeper depth of field when compared to a crop sensor. Here is a good Depth of Field Calculator. Here’s a few rules:
To Increase Depth of Field
To Decrease Depth of Field
Shorter focal length
Longer focal length
Move away from subject
Move towards subject
Here are some general aperture guidelines I like to follow.
Macro photography – When shooting bugs and other small objects at 1:1, I find f/11 a good starting point.
Creative shooting – Photos where I am shooting a single object and trying to create a blurred background, I will generally shoot f/1.4 to f/2.8. This is often called Bokeh Photography.
Sports – Most of my sports shooting is done at f/2.8
Indoor portrait – For sigle people I will shoot f/2.8 to f/4. For multiple people I will generally shoot f/5.6 to f/8
Outdoor portrait – If I can get the room to get further back from my subjects then f/2.0 to f/5.6 is the most common.
Landscape photography – I will generally shoot at f/11 to f/22