Do you want to know what the depth of field and how to master it to achieve spectacular photos?
Today I’m going to tell you how to get the photo you want and don’t have to settle for the one that you get. We’ll see why sometimes you don’t get that out-of-focus background you crave or why you can’t get what you want in focus.
Mastering depth of field can mean a before and after in your photographs. And this goes beyond large aperture or small aperture.
As always, I’m going to tell you in the language that characterizes the blog, the language of earthlings 😉 . Avoiding technicalities and complex explanations. We are here to make things easier, not to complicate them ;). You won’t regret it!
And if you’re looking to master Manual Mode photography, we have this mega guide (link above) where we explain it in depth so you can lose your fear once and for all.
So, 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 focused sharp point, and the farthest focused sharp point within the frame of a photograph. The in-focus or sharp area of an image in contrast to other areas of lesser focus.
A lens can focus on only one point within a frame, not several. However, that focused point can be wider or narrower, depending on the capabilities of the lens.
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 looks sharp in contrast to the rest out of focus, it is a photograph with a shallow depth of field. So much for that, right?
In case there is still any doubt, let’s look at it with a graph and two example photos.
On the left you can see that we have achieved a great depth of fieldso that the camera focuses us over a wide distance, practically from 5 to 15 o’clock.
On the other hand, on the right side we have greatly reduced the depth of fieldthat is, the area in focus, so that everything in the photo will be out of focus except for what is between 9 and 11 in this case.
Now look at these two images so that you can understand the concept much better:
As you can see, the whole scene is in focus, you can distinguish the details of all the planes, 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 closer plane we intuit or see more blurred and the background becomes a practically smooth area.
Depth of field and plane of focus.
One important piece of information before continuing. The plane of focus is perpendicular to the shooting direction. If you look at this diagram, when taking the picture, if any of the subjects were to step forward, with a very shallow depth of field, they could be out of focus.
Therefore, when using large apertures we must be careful about focusing first and then reframing, because we can leave the subject out of focus.
What is depth of field for?
Depth of field, rather than a technical concept, which it is, is a. compositional instrument. It is the technique at the service of creativity. Using it you can compose the image as you wish, erase annoying backgrounds, focus attention on a single point of the image, achieve spectacular portraits, or show a whole landscape from beginning to end.
Depth of field allows you to be master of the image. Modify the scene to your liking.
If you think about it, it’s as if you had a magic wand to make elements disappear, or to tell the viewer without a single word where to look.
Next, I’m going to give you practical examples in which the depth of field plays an essential role.
- Large depth of field: is generally used in situations where we want everything to be in focus, e.g. nature photography, landscapes, mountains, etc.
- Small depth of field: we resort to it in situations where 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 mastering it means a before and after in your photographs? ;P Well, let’s continue to get the most out of it. Today I have decided to clear up all your doubts and open up a new universe for you.
What factors influence the depth of field?
There are four factors that influence depth of field. Let’s look at them one by one.
This is a factor that is limited by the equipment, more specifically, from the objective. The diaphragm is the part of your lens that regulates light intake.
The lower the number (f/), the larger the aperture, the more light will enter and the shallower the depth of field. Aperture is the first step we take to control depth of field.
Just to be clear, as the concept is confusing when expressed backwards:
- LARGE OPENING.⇒ shallow depth of field (shallow area in focus).
- small aperture⇒ large depth of field (lots of area in focus).
The of the target. For example, the lenses that usually come with the kit usually have a maximum aperture of f/3.5. Some go no wider than f/5.6 even. That means that the ability to defocus is much more limited than with a brighter lens.
If that’s your case, you’ve just found an answer to why you don’t get those portraits where only the eyes are in focus.
So that you don’t get discouraged, you should know that there are some tricks that can help you achieve greater focus, we’ll see them in a moment.
There are many reasons to buy a bright lens (with aperture of at least f/2) but if the kit one is the lens you have, learn to make the most of it. The biggest limitation can become yourself ;).
Other limitations are the side effects. It’s not a matter of opening or closing the diaphragm and that’s it. It has consequences. If you know anything about the light triangle, you’ll know which ones. If not, go to the article in the link. Here’s a summary graphic.
The more you open the diaphragm the more light will come in, 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 getting blurred or noisy pictures).
This is another topic, but I had to tell you about it, so don’t get frustrated if you don’t get the expected results! The light triangle is a photographic concept that you must learn well before embarking on mastering depth of field if you don’t want to fail in the attempt.
Another factor that influences depth of field is the distance from which you focus. You may also be interested to know that the same depth of field is not usually achieved behind the plane of focus as in front of it. Usually behind the focused plane there will be greater depth of field.
If you want to achieve the same depth of field in front as behind, you will have to get closer to the focus subject.
In this graph I think you will see it more clearly. Using the same focal length and aperture, as we move away from the subject (the plane we want to focus on) we find that there is more area behind that is in focus (the pink area is the one that is in focus).
Therefore, a trick to get more blur is to get closer to the subject.
Here you may see it even clearer. The shaded area is the area that will be in focus.
By now, I understand that you know what focal length is, otherwise, pause and go to this article. If you already know, we’ll continue.
The focal length you use also affects the depth of field. This is the relationship considering the same focus distance, aperture, etc. :
- A longer focal length (e.g. 200 mm)⇒shallower depth of field.
- A shorter focal length (e.g. 35mm)⇒greater depth of field.
This is one of the reasons why wide-angle lenses 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 in focus.
Circle of confusion
First of all, you should know that the circle of confusion is usually predetermined in calculators for common parameters (maximum magnifications 20x25cm, viewing distance 25cm and a “standard” visual acuity).
However, you are interested in knowing this value if you want to make much larger magnifications and control very very well which parts are in focus and which are not.
Now to the subject, the circle of confusion is the maximum size that a blurred spot in the image must have on the camera sensor so that the observer can see it sharp in the final image. It depends on the size of the sensor, the visual acuity of the viewer, the distance from which the photo will be viewed and the print size. 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 the default value and you will achieve very acceptable results.
Depth of field simulator
To see all these concepts more clearly and without moving from the chair, I tell you a secret, there are what are called photographic simulators and there is one, in particular, that comes in handy to understand all this we are talking about. It 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, make a note in your diary of the next outing to practice it with your camera!
In short, how do you get more or less depth of field?
Get a greater depth of field (more sharp area):
- With more closed or small openings (between f/8 and f/22).
- Short focal lengths (10-35mm).
- Longer distance of focus (zooming out).
- Using the hyperfocal distance (we will see its importance in another section).
- With editing. Sometimes, we don’t have enough light to close the diaphragm enough or we have to shoot at a very fast speed because it is a moving scene. If you put together in the editor several images with shallow depth of field with the focus on the different planes, you can achieve an image with a greater depth of field.
Get a shallower depth of field (more area out of focus):
- Large apertures or wide open (f/1.4, f/3.5).
- Long focal lengths (70-400mm).
- Focusing from a shorter distance (move closer to the object you want to focus on).
This does not mean that you have to comply with each and every point, but each point will help you achieve a greater or lesser depth of field.
For example, back to the kit lens, you want a shallow depth of field to take a portrait with the background out of focus. I’m going to use as an example my lens which is an 18-55mm f/3.5-5.6. To achieve a greater blur would have to:
- Approach the subject.
- Move the subject away from the background (this we haven’t said) but the farther away from the background, the more out of focus it will appear.
- Shoot with the longest focal length, in this case 55mm.
- Shoot with the largest aperture, which being 55mm focal length the maximum aperture is f/5.6 (f/3.5 would be for an 18mm focal length).
As you can see, some of these tricks can help you to achieve more blur with the kit lens 😉 Get them right!
And what does hyperfocal distance have to do with it, what is it for?
This concept will be useful when shooting landscapes or stars, especially with short focal length lenses (10-35mm). It will help you to achieve the maximum depth of field. To calculate it there are tables and calculators. Here you have all the information about the extended hyperfocal.
But before going on I leave you a trick: when you have the hyperfocal distance, go over, focus at a distance slightly greater than the one you have calculated. If you don’t reach it, even if it’s just a little, whatever is on the horizon will be out of focus. Better to overdo it, this way you can be sure.
Here is a video summary of how to calculate the hyperfocal.
Depth of field calculator
There are applications that can help you calculate depth of field. For example this. With it you will be able to calculate the necessary adjustments to achieve the level of sharpness you want. Other free applications:
It won’t do you any good to have reached the end of the article if you don’t put into practice what you have read. Go to the simulator, work through it until it’s clear in your head. Then put it into practice. That’s how you learn. Reading is the first step on the way. The goal is reached by walking.
If you have found it useful, please share it, maybe we can clarify some doubts to some of your contacts. And if there is anything that is not clear to you, don’t hesitate, leave your comment below and we will try to clarify it. Thank you and see you soon!