Find out how to take sharp landscape photographs, and how to create dreamy blurred backgrounds to isolate your portrait subjects. All with one of the most important photographic tools – depth of field.
Words and Photography by Urth HQ
Depth of field, or often abbreviated as DoF, is arguably one of the defining characteristics of the medium of photography. We touched on depth of field photography in A Complete Guide to Aperture, mostly in relation to aperture’s ability to creatively implement blur as a tool in isolating your subject. But did you know that depth of field is influenced by other factors? Let’s unpack this important photographic concept here.
What is Depth of Field?
A technical definition of depth of field is, “the distance between the nearest and the furthest objects giving a focused image”. It’s the zone within the image that appears in focus. To elaborate, did you know that only one precise area of your image is in focus? The cameras we use are only capable of focussing sharply on one point.
This sounds like a lie, right? We’ve all taken a great landscape photograph where everything is in focus from the rocks in the foreground to the mountain range in the back. Well, it’s no lie. Cameras do only focus sharply on one point, but this is where depth of field comes into play.
‘Acceptably sharp’ is a term often associated with depth of field and is used to demonstrate what should be a gradual transition from sharp to unsharp. In other words, a seemingly sharp landscape photograph is only acceptably sharp because of the large depth of field. So, although we focused our camera on the river in the middle of the frame, we will have acceptable sharpness from the rocks in the foreground to the mountain range in the back because of this gradual, very slow transition to unsharp. It’s very hard for the naked eye to notice this transition.
Depth of Field Chart
Before we go any further, let’s take a look at this depth of field chart to see the clear difference between a shallow depth of field and a deep or large depth of field.
What a Shallow Depth of Field Looks Like
A shallow depth of field is achieved mainly by widening your aperture, creating a larger f-stop value to allow more light to pass through the opening of your lens. You will see this time and time again in portraiture where a photographer elects to isolate the subject from a busy scene, blurring the background and bringing focus solely to the subject. This technique is also referred to as a shallow depth of focus.
See some shallow depth of field examples below.
What a Deep Depth of Field Looks Like
Traditionally, the hallmark of any great landscape photograph is the appearance of sharpness throughout the entire scene. A deep depth of field is achieved by narrowing the aperture of your lens. There are a number of reasons why narrowing your aperture will create an overall level of depth in your photograph that include geometry and lens construction. Let’s leave the science lesson for another day but with your interest piqued, you can find out more about why a small aperture increases depth of field here.
See some deep depth of field examples below.
How to Change Depth of Field
Before setting up your tripod for a long exposure landscape or before framing your handheld scene, assign intent to the result. What do you want to achieve with this shot? Often, you’ll find that aperture and depth of field are priorities.
Then, before rotating any dials on your camera, remember that large apertures produce a large amount of background or foreground blur. And remember that small apertures produce smaller amounts of blur.
Refer to the aperture/depth of field scale chart above to see how aperture size determines depth of field.
But aperture isn’t the only element to factor into the depth of field equation. Camera-subject distance, camera sensor size and the focal length of your lens all play their role.
The distance between the camera and the subject… pretty self-explanatory. The shorter the distance between you and your subject, the smaller the depth of field will be. Putting some more distance and frame between you and your subject will therefore create more blur and a shallower depth of field.
SENSOR SIZE & FOCAL LENGTH
Entire studies ought to be written on the complicated numerical effect a camera sensor’s size and lens focal length has on depth of field. There’s no golden rule and no cut-to-the-chase answer. It all depends on how you draw comparisons between multifarious factors.
For some comprehensive reading on this topic, check out this link.
How to Decrease Depth of Field
We now know that increasing or widening your aperture will decrease your depth of field and produce a far shallower, razor-thin focus. To achieve this technique, you want to set your aperture value to somewhere between f/1.4 – f/5.6.
If wanting to decrease your depth of field further, try some of the other techniques outlined above such as adding more camera-subject distance.
How to Increase Depth of Field
Set your aperture value anywhere between f/11 and f/22 if wanting to capture a scene with the appearance of sharpness from front to back. Try moving closer to your subject.
Depth of field photography can be a complicated task if calculating depth of field through camera-subject distance, camera sensor size and lens focal length, especially if you’re just beginning photography.
We recommend sticking to the basics and experiment just with changing your f-stop first, as it will greatly improve your photographic skills.
The beauty of depth of field is in the manipulation of blur within your image. From the razor-thin perspective of a subject’s face to a tack-sharp landscape, decreasing and increasing depth of field to achieve a specific effect is something all photographers should aim to master.