UNDERSTANDING DEPTH OF FIELD
What? Am I crazy? Would I really want to talk about such a technical subject? YUP!!
I’ll tell you how I feel about the subject of “depth of field”. Absolutely, that once you understand this principle, your photography will take on a whole new meaning. Serious. I remember teaching this back when I worked at a photographic store. People would come into the store, and ask me how to get more in focus in their pictures, because they saw it in a picture, or, how could they take a picture and have only the subject be in focus and have everything out of focus. Well, that is “depth of field”. And that is totally understanding your “F-stop” or aperture setting. On some or most cameras you may have a control for shutter speed priority, and then you may have the infamous: AV or Aperture value. What do you do with that? That is the subject today.
Well, I have found several articles from professionals that explain it all. I could go on and do it myself, but, they have the pictures already in their article that shows how it works, so, hey! why not use theirs. I will give them credit for sure. I appreciate their input. And I know they were totally excited that they discovered it, and what it means to their picture taking experience. So, let’s do it:
Depth of field (DOF) is one of the most important factors in determining the look and feel of a photograph. It’s also the most overlooked for photographers moving from a point-and-shoot camera to a DSLR camera. With a DSLR, you have a huge amount of control over depth of field, and you should know how to utilize that control.
“Hot August Nights 2014” captured by Robert Longbrake
Depth of field refers to the distance (depth) from the focus point that a photo will be sharp, while the rest becomes blurry. A large, or wide, depth of field results in much of the photo in focus.
“The Sky Rider” captured by Michael Greene
A small, or narrow, depth of field results in much more of the photo out of focus.
“Untitled” captured by Laura Matkutė
Neither approach is better or right, and which depth of field to use is up to you. You may have different reasons for choosing a certain depth of field, including artistic effect, bringing attention to a subject, or crisp representation of a scene.
There are four main factors that control depth of field: lens aperture, lens focal length, subject distance, and sensor size. Your sensor is pretty well set, so you won’t have much luck changing that. Your focal length and distance to the subject are usually determined by your choice of composition. So the lens aperture is your primary control over depth of field.
Before I get to the tips, let’s get a few things straight:
BIG APERTURE = SMALL F-NUMBER = SMALL DEPTH OF FIELD
SMALL APERTURE = BIG F-NUMBER = BIG DEPTH OF FIELD
Large apertures (small f-numbers) cause a narrow DOF, while small apertures (large f-numbers) cause a wide DOF. To bring attention to a subject by blurring a background (selective focus), shoot with f-numbers like f/2.8, f/4, or f/5.6. To bring the whole scene into focus, shoot with f-numbers like f/16 or f/22.
If you want to bring an entire scene into focus and keep it sharp, use a small aperture. But be careful not to go too small. Lens sharpness starts to deteriorate at the smallest apertures. Use enough to get what you want, and no more. You may have to experiment a bit to get a feel for how your camera and lenses work at different apertures.
The DOF extends behind and in front of the point of focus. It usually extends further behind than in front, though. So keep this in mind when choosing your focus point; you’ll want to focus about a third of the way into the scene rather than halfway.
“Road Together” captured by Robert Longbrake
As you stop down the lens for greater depth of field, you’re also letting less light into the camera. To compensate for this and maintain correct exposure, you’ll need to either use longer shutter speeds or a higher ISO. The ISO can only be increased so much before noise artifacts become an issue, so you’ll most likely want to lengthen your shutter speed. If your shutter speed is too long, you’ll need a tripod (or some type of stabilization) to deal with this.
When looking through the viewfinder of a DSLR camera, you’re seeing the world through the lens. You can easily see your resulting composition and point of focus, but the depth of field you’re witnessing is a little false. You’re seeing the resulting depth of field for the largest aperture of the lens, no matter what f-number you’ve chosen. Most newer cameras have a feature called DOF Preview that allows you to stop the lens down to the chosen aperture so you can see the true depth of field.
As I mentioned, your focal length is usually determined by your choice of composition, but you should know how it affects your depth of field. Longer focal lengths (200mm) have less depth of field than shorter focal lengths (35mm). Just keep this in mind when you’re trying to achieve a certain depth of field—you may need to alter your focal length in addition to your aperture.
So there are your basic tips for controlling your depth of field when taking photographs. The best way to learn how to control DOF is to set your camera to aperture priority mode and go take some pictures. Photograph the same subject many different times while altering the aperture, point of focus, and focal length (if you have multiple lenses or a zoom lens). Either write down the settings you used for each picture or use software to view your camera’s settings while you look through the pictures on your computer. You’ll begin to see how these different factors affect your photos.
About the Author:
Brian Auer is from Epic Edits, which is a resource and community for photography enthusiasts of all experience levels.
JP Morgan goes back to the basics of depth of field to show how you can use shallow versus scenic Depth of Field to become more creative with your images. In the video JP is on location at Vasquez Rocks in California doing a fashion shoot. The model looks stunning in a red dress, contrasting against the brown monochromatic colors of the backdrop of rocks. Combining the striking color contrasts with creative lens options, JP walks us through the depth of field basics, revisited in a different way:
To start with, JP uses a two light setup with sun as a rim light and a strobe as key lighting. He uses a Dynolight travel head with Photoflex Softbox on her face, keeping her head turned slightly from the sun to avoid it hitting her nose and face. He then keeps the same basic frame set up and shows us how the different lens (and later, aperture/depth of field) options effect the image. This video revisits a basic principle in a different way, JP explains it quite eloquently.
“Every time I do a lesson where I stop and look at a basic principle of photography, I learn something. Even though I have shot for years, using different lenses and different apertures, it’s just good to step back, look at the basics, understand them a little better, and then you can apply them more effectively.”
We are first given an example, shooting at F/11 and 160 ISO without the added Softbox and just the sun framing the model’s body on the left side.
He then shows us the difference after adding the artificial lighting, striving for soft light on her face and body.
Finally, he plays with three different lenses and the same depth of field, keeping the model the same size in the frame to show us the dramatic creative effects one can create by simply changing lenses.
The difficulty with using 100 and 200 mm lenses in fashion photography is having to have the room to work, because of having to back away from the subject. However, if the situation allows, lenses can be used to create very dramatic effects. In the last image with a 200 mm lens at 2.8, you get more of a traditional fashion photography kind of feel, but it drowns out the entire background so you cannot even tell where she is, taking away all texture.
Like JP says,
“There is no right or wrong choice, just another tool to be used to tell your story.”
PHOTOGRAPHY DEPTH OF FIELD:
One the most fundamental techniques necessary to really to master creative photography is depth of field. It was always a bit of a mystery to me because of the link to aperture and understanding all those back to front f-numbers. I think it was more of a mental block, though, because it’s actually quite easy to grasp.
“Field Flower with Mayon Volcano” captured by Peter Emmett
Creatively you are able to do more with your photography and as you learn digital photography you will find using depth of field key to great images. You can use it to blur out backgrounds while the subject remains pin sharp or to create an image perfectly in focus from front to back, as in great landscape photos.
It’s quite simple. It’s the amount of a scene that is in focus in front of your point of focus or behind it. Depth of field is more simply understood as depth of focus: how much of the image is in focus. A lens can only focus at one point which is the sharpest, most in focus point in the photo. But what you can do by using depth of field is to control the perceived zone of focus. This will differ when shooting different subjects or scenes.
Now, there are three main factors that affect depth of field. Firstly, the aperture you are using, secondly the focal length of the lens, and thirdly the focusing distance. All of these will impact the depth of field. Each of these will affect depth of field, so in order to control it effectively it’s necessary to master each one of them.
When shooting an image using a 28mm wide angle lens at, say, f/5.6 you will see a much greater depth of field as compared to a 400mm at the same aperture. When using different lenses understand what the impact will be so that you can creatively use the resulting depth of field.
On a lens you have possible apertures ranging from f/1.2 all the way up to f/32, and each of these lens openings will have an effect on depth of field. If shooting on the extremes, like f/32, you’ll find that it results in quite a considerable difference than when you shoot at f/2.8. Then when shooting using the mid-range numbers the depth of field will again be different. An aperture of f/2.8 will have a very shallow depth of field while f/32 will show sharp focus throughout the whole image.
“on call” captured by Tatyana Druz
How far you are to the point of focus is another factor to consider. When using any lens, the depth of field will increase the further the focusing distance. If you focus on an object three meters away, and if you focus on something 300 meters in the distance, the depth of field will be greater. So in other words, when the subject is far away from the camera there will be a greater depth of field and more of the image will be in focus.
Most of us have taken landscape images where most of the scene is in focus. This is true when you’re shooting scenes of fields and trees and boats on the sea. The way in which this is achieved is by setting your aperture to the highest number, e.g. f/22 and above, which means the smallest aperture. Virtually the whole scene from foreground to background is in focus. But this changes when choosing a wide aperture or a small f-number on the lens. Here you would only use this setting to shoot something you want to isolate such as a face in a portrait. The background gets blurred out and the face is in crisp focus. You would also use this when shooting close-ups of flowers or animals in a zoo where you don’t want to see the background or the bars or fence in the foreground.
So, as you can see, depth of field is really quite simple. Blurred out backgrounds use a large aperture and landscapes that need to be in focus from foreground all the way through to the background use a small aperture. The key as you learn digital photography is to experiment with all settings and then practice, practice, practice!
About the Author:
Wayne Turner has been teaching photography for 25 years and has written three books on photography. He has produced 21 Steps to Perfect Photos; a program of learner-based training using outcomes based education.
3 Great articles on depth of field. I hope you all read through these very carefully, and now understand the magic you have in your hands.
Let’s give credit to the authors of these articles:
1- Brian Auer
2- JP Morgan
3- Wayne Turner
All 3 of these authors come from the website: PictureCorrect. Thanks to all of you for producing great work.
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