Do you want to know what is depth of field and how to master it to achieve spectacular photos?
Today I am going to tell you how to get the photo you want and not have to settle for the one you you get out. We will see why sometimes you don’t get that unfocused background that you crave so much or why you can’t get what you want to be in focus.
Mastering the depth of field can be a before and after in your photographs. And this happens by going beyond large opening or small opening.
As always, I’m going to tell you in the language that characterizes the blog, that of the earthlings 😉 . Avoiding technicalities and complex explanations. That we are here to make things easier, not to complicate them ;). You stay? You will not regret!
And if what you are looking for is to master photography in Manual Mode, we have this mega guide (previous link) where we explain it in depth so that you lose your fear once and for all.
Come on, without further ado, let’s get to today’s topic:
What is depth of field?
Depth of field is a term used in photography to refer to the distance between the closest sharp point of focus and the farthest sharp point of focus within the frame of a photograph. The in-focus or sharp area of ​​an image in contrast to other less-focused areas.
A lens can only focus on one point within a frame, not multiple points. Of course, that focused point can be broader or smaller, as we want and depending on the capabilities of said objective.
The area of ​​the image that is sharp and in focus determines the depth of field.
Mario explains it to you in a very graphic and fun way in this video:
Therefore, an image where everything or almost everything is in focus (or sharp) has a large depth of field. If, on the other hand, only a small part of the scene is sharp in contrast to the rest out of focus, it is a photograph with a small depth of field. So far, of course, right?
In case there is still any doubt, we are going to see it with a graph and two example photos.
On the left you can see what we have achieved a large depth of fieldso that the camera focuses on us a wide distance, practically from 5 to 15.
Instead, on the right side we have greatly reduced depth of fieldthat is, the area in focus, so that in the photo everything will be out of focus except what is between 9 and 11 in this case.
Now look at these two images so you can understand the concept much better:
As you can see, the entire scene is in focus, details of all planes can be distinguished, from the rocks and grass in the foreground, to the mountains in the background with their snow.
On the other hand, in the following photograph we can only observe a few flowers with their stems, what is in the closest plane we intuit or see more blurred and the background becomes a practically smooth area.
Depth of field and plane of focus
An important fact before continuing. The plane of focus is perpendicular to the shooting direction. If you look at this scheme, when taking the photo, if any of the portrayed took a step forward, with a very small depth of field, it could be out of focus.
For this reason, when we use large apertures, we must be careful with what to focus first and reframe later, because we can leave the protagonist out of focus.
What is depth of field for?
Depth of field, more than a technical concept, which it is, is a compositional instrument. It is technique at the service of creativity. Using this you can compose the image as you please, erase annoying backgrounds, focus attention on a single point of the image, achieve spectacular portraits, or show an entire landscape from start to finish.
The depth of field allows you to be image owner. Modify the scene to your liking.
If you think about it, it’s like you have a magic wand to make elements disappear, or to tell the viewer without a single word where to look.
Next, I am going to give you practical examples in which the depth of field plays an essential role.
- Large depth of field: It is usually used, generally, in situations in which we want everything to appear in focus, for example nature photography, landscapes, mountains, etc.
- Small depth of field: we resort to it in situations in which we are interested in capturing the viewer’s attention and focusing it on a specific point, for example, to give prominence to the subject of a portrait, or to highlight one object among several.
Do you understand now why dominating it supposes a before and after in your photographs? ;P Well, let’s continue to get the most out of it. Today I have proposed to clear all your doubts and make a new universe open before you.
What factors influence depth of field?
Four factors influence depth of field. Let’s see one by one.
diaphragm opening
This is a factor that is limited by team, more specifically objective. The diaphragm is the part of your lens that regulates the entry of light.
At a lower number (f/), the aperture of the diaphragm will be larger, more light will enter and the depth of field will be smaller. Aperture is the first step we take to control depth of field.
To make it clear, since the concept is confusing when expressed backwards:
- large opening⇒ small depth of field (little area in focus)
- small opening⇒ large depth of field (a lot of area in focus)
Limitations?
The Of the objective. For example, the lenses that usually come with the kit usually have a maximum aperture of f/3.5. Some don’t even go past f/5.6. This means that the ability to defocus is much more limited than with a brighter lens.
If this is your case, you just found an answer to why you don’t get those portraits where only the eyes appear in focus.
So that you do not get discouraged, you should know that there are some tricks that can help you achieve a greater focus, we will see them soon.
There are many reasons to get a bright lens (with an aperture of at least f/2) but if the kit lens is the lens you have, learn how to get the most out of it. The biggest limitation can be oneself ;).
Other limitations are the Collateral damage. It is not about opening or closing the diaphragm and that’s it. It has consequences. If you know something about the triangle of light, you will already know which ones. If not, go to the linked article. Here is a summary chart.
The more you open the diaphragm, the more light will enter, the more you close it, the less light. Which, to achieve a correct exposure, you will need to play with other values ​​such as ISO or shutter speed (with the risk of obtaining blurred photos or with a lot of noise).
This is another topic, but I had to tell you, don’t get frustrated if you don’t get the expected results! The triangle of light is a photo concept that you should learn well before launching to dominate the depth of field if you do not want to fail in the attempt.
Focus distance
Another factor that influences the depth of field is the distance from which you focus. It also interests you to know that the same depth of field is not usually achieved behind as in front of the plane of focus. Normally behind the focused plane there will be a greater depth of field.
If you want to achieve the same depth of field from the front as from the back, you will need to get closer to the subject in focus.
In this graph I think you will see it more clearly. Using the same focal length and the same aperture, as we move away from the subject (from the plane we want to focus on) we find that there is more area behind that remains in focus (the pink area is the one that remains in focus).
Therefore, a trick to achieve greater blur is to get closer to the subject.
Here you may see it even more clearly. The shaded area is the area that will be in focus.
Focal distance
By now I understand you know what focal length is, otherwise pause and go to this article. If you already know, continue.
The focal length you use also affects depth of field. This is the ratio considering the same focus distance, aperture, etc. :
- A longer focal length (eg 200mm)⇒shallow depth of field
- A shorter focal length (eg 35mm)⇒greater depth of field
This is one of the reasons why wide angles are more suitable for landscape photography, because in addition to covering a larger portion of the scene, they achieve greater depth of field or area of ​​focus.
circle of confusion
First of all, you should know that the circle of confusion is usually predetermined in calculators for some common parameters (maximum magnifications 20x25cm, viewing distance 25cm and a “standard” visual acuity).
Now, you are interested in knowing this value if you want to make much larger enlargements and control very well which parts are in focus and which are not.
Now to the topic, the circle of confusion is the maximum size that a blurry point in the image must have on the camera sensor so that the observer can see it clearly in the final image. This depends on the size of the sensor, the visual acuity of the observer, the distance from which the photo will be viewed, and the size of the print. And how do you know what its value is? Here is a calculator.
But I remind you that, for normal situations, the depth of field calculator will set you the default value and you will achieve very acceptable results.
depth of field simulator
To see all these concepts more clearly and without leaving your chair, I’ll tell you a secret, there are what are called photographic simulators and there is one, in particular, that comes to you from the cinema to understand all this we are talking about. This is DOF ​​simulator.
Leave it open in another window, when you finish reading the article, go to the simulator and practice these concepts. When you see that you have it clear, write down the next outing in your agenda to practice it with your camera!
In short, how to get more or less depth of field?
get one greater depth field (plus sharp area):
- With tighter or smaller openings (between f/8 and f/22).
- short focal lengths (10-35mm).
- greater distance focus (moving away).
- Using the hyperfocal distance (in another section we will see its importance).
- With the edit. Sometimes we don’t have light to stop down enough or we have to shoot very fast because it’s a moving scene. If you put several images with shallow depth of field together in the editor with the focus on the different planes, you can achieve an image with a greater depth of field.
get one shallower depth field (plus area out of focus):
- Openings…