8 Things You Need to Know About Depth of Field (DoF)
There are tons of settings on your DSLR for you to master—here are the things you need to know about depth of field.
As a new photographer, it can be difficult to understand the various settings on your DSLR and how they all work together to create an image. Maybe you understand some things like shutter speed and composition, along with the tips for using the rule of thirds in photography, but you find the more technical aspects of photography a bit more elusive and complex, like depth of field.
Depth of field is one of these more technical and complicated aspects of photography, but here are eight things you need to know about depth of field to enhance each of your photos and capture each of your subjects with as much clarity as possible.
Depth of Field, in Depth
Understanding depth of field takes some time, and a mixture of understanding the theory behind it along with practice. Depth of field is a term referring to the range of acceptable sharpness in your photos—it's the space that exists between objects in your photo, and whether they appear sharp or blurry. Your subject, in focus, should be far enough away that the aspects of it are sharp, allowing for a greater attention to be paid on what the subject of your photograph is. For example, if you're taking a portrait, and your subject is standing in front of a tree, you want the background, the branches, and the leaves blurred, and the subject's eyes, hair, and shoulders should be sharp and clear in the photograph.
Depth of field is important in all photography, but it's especially important with macro shots, landscapes, and portraits. With landscapes, you'll probably want a deeper depth of field, whereas with macro shots, you'll want a shallow depth of field.
Depth of field is one of the areas that really helps you carve your artistic intentions into your photographs—aperture and depth of field are all about what is in focus, and what is not; and therefore, you can make plenty of statements by really narrowing your focus on specific subjects, and highlighting them, even if they aren't conventional things that you'd focus on.
Adjusting the Depth of Field in Your Photos
The main way you can adjust the DoF in your photos is by adjusting the aperture. The aperture refers to the amount of light your lens is allowing into the camera sensors. On your camera, you would adjust the f-stop settings in order to adjust the aperture. Larger f-stop numbers correlate to small apertures, and smaller f-stop numbers mean a larger aperture.
Changing the Distance Between Your Camera and the Subject
Adjusting how close your camera is to the subject is perhaps the easiest way to adjust your depth of field. By backing up, or moving closer to your subject, you can adjust the size of the area that is acceptably sharp, giving you complete control over the rules of composition with your photo.
The focal length of your lens can also be adjusted. Focal length refers to the angle from which the camera will view the subject you're trying to capture. This therefore, determines, how much of the landscape will be captured, and how big or small different objects in the scene will appear in the photo. You can adjust the focal length using settings on your camera, but you can also enhance those settings by switching lenses. The length of the lens you choose affects the focal lengths you can work with.
Size of the Sensors
The third element that can affect depth of field is the sensor size on your camera. This feature is a bit more limiting, as this refers to the actual size of your DSLR, and the sensors inside of it that allow you to capture images. If your camera is larger and has larger sensors, then it will be able to capture more information from the subjects you're trying to photograph than a smaller camera with smaller sensors. The best DSLR cameras for beginners have a wide variety of sensors you can choose from, so be sure to do your research before bringing one to the register.
Determining Which Lens to Use
As mentioned previously, your lenses have specific focal lengths, meaning the distance between the lens and the image sensors in the lens and camera. Shorter focal lengths will allow you to capture more of a scene, whereas longer focal lengths will allow you to capture subjects that are farther away from you, as if you were standing closer to them—and they do this by adjusting the angle from which you're taking a photo, clearly separating your subject from the background.
A wide angle lens has a smaller focal length, and can therefore take in more of a scene you're trying to capture—so much so that the image can look a bit distorted, like a fishbowl.
If you're taking portraits specifically, you may want to consider investing in telephoto lenses, because their focal lengths automatically separate the subject from the background, which makes focusing and capturing your subject in a portrait a lot easier.
Hyperfocal distance is the distance between the lens and the closest object that is in focus. Understanding hyperfocal distance comes in handy for those moments when you wish you could get an entire scene in focus at once, and you don't know where to focus your camera—it's then that hyperfocal distance can give you some direction. Typically, this concept says you should get the closest third of the scene in focus. You adjust hyperfocal distance by adjusting how close or far your camera is from your subject, and by playing with the aperture settings on your camera to get the desired sharpness in specific spots in your images.
The Aptly Named Circle of Confusion
If you've heard of the circle of confusion before, and felt only like you were trapped in it despite your attempts to understand it, fear not—it's an odd concept.
The circle of confusion encompasses the various aperture values that your specific lens is able to use to focus on a subject. However, as Annie Leibovitz writes in her article, "Learn About Depth of Field in Photography" for Masterclass:
"The circle of confusion is also the degree of tolerance that the human eye has before it distinguishes between an out of focus object and an in focus object. In other words, while an image may not actually be perfectly in focus, it appears in focus because the human eye can’t actually distinguish between something that is slightly out of focus and something that is perfectly in focus."
You'll find, in photography, that a lot of these concepts refer to ranges and areas where no specific numbers or measurements can be given to ensure that you make the proper adjustments for each of your photos. However, with time and practice, you'll learn to check each of these areas in each photo you take to ensure that you're manipulating the light and using your camera's lenses and settings so you know that you're capturing the image that you want to create.
Using Your Depth of Photography Knowledge
Put simply, your camera is just manipulating light to create a photo—that's all photography is, so it's highly beneficial for you to understand the different ways that you can manipulate light so that you can understand when something is out of balance. And as Pablo Picasso said:
"Learn the rules like a pro, so you can break them like an artist."
Once you learn the basics, and you become comfortable with the different ways that small adjustments impact your photos, you can play around with the settings and your composition a bit more to find artistic perspectives that tell more satisfying stories.
Hopefully these things you need to know about depth of field have expanded your understanding of your DSLR and the process of taking a photograph, and will get you one step closer to the perfect photograph.