WHAT YOU NEED TO KNOW TO MASTER THE DEPTH OF FIELD

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. If in the article The Depth of Field: Explanatory Graph find a clear, concrete and concise explanation of what is the depth of field, today we take another step and tell you how to master it. Why sometimes you don't get that unfocused background that you crave so much or why you don't get what you want to be in focus. In this article I will give you tips and tricks so that the depth of field does not resist you anymore and you get the photo you want, and you do not have to settle for the one you get . And I'm going to do it in the language that characterizes the blog, that of the earthlings;). Avoiding complex technicalities and explanations. That here we are to facilitate things , not to complicate them;). You stay? You will not regret!

WHAT IS DEPTH OF FIELD?

To master a concept you must first know it, right? Well let's start here. Depth of field is the sharp or focused area of an image. Mario explains it to you in a very graphic and fun way in this video: Therefore, an image where all 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 small depth of field. So far, of course, right? Even better, we see it with a graph and with two sample photos. Now look at these two images so you can understand the concept much better:

Large depth of field

As you can see, the whole scene is in focus, you can distinguish the details of all the planes, from the rocks and the grass in the foreground, to the mountains in the background with its snow.

Small depth of field

On the other hand, in this photograph we can only observe a few flowers with their stems, what we have in the closest plane is intuited or we see more blurry and the background becomes a practically smooth area. An important fact before continuing. The focus plane is perpendicular to the shooting direction. If you look at this scheme, when taking the photo, the bird above would be out of the focus plane, with a very small depth of field could go out of focus.

The focus is perpendicular to the shot

WHAT IS THE DEPTH OF FIELD FOR?

The depth of field, rather than a technical concept, which is it, is a compositional instrument. It is the technique at the service of creativity. Using this 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 an entire landscape from beginning to end. The depth of field allows you to own the image. Modify the scene to your liking. If you think about it, it's as if you had a magic wand to make items disappear, or to tell the viewer without a single word where to look. Are you now understanding why mastering it means a before and after in your photographs? ; P Then let's continue to get the most out of it. Today I have decided to clear all your doubts and get a new universe to open before you.

WHAT DEPTH OF FIELD DEPENDS ON?

There are four factors that influence depth of field. Let's see one by one.

DIAPHRAGM OPENING

This is a factor that depends on the team, more specifically the objective. The diaphragm is the part of your goal 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. In turn, it is the most used to control depth of field, as it is the easiest to handle. To be clear, because the concept is confusing when expressed upside down:

large aperture ? small depth of field (little focused area)

small aperture ? large depth of field (much focused area)

LIMITATIONS?

Those of the objective. For example, the objectives that usually come with the kit do not usually have a maximum aperture of more than f / 3.5. Some do not even pass f / 5.6. That means the ability to blur is much more limited. If this is your case, you just found an answer to why you don't get those portraits where only the eyes appear focused. So that you don't get discouraged, you should know that there are some tricks that can help you achieve a greater focus, now we will see them later. There are many reasons to acquire a luminous objective (with opening of at least f / 2) but if the one of the kit is the objective that you have, learn to make the most of it. The biggest limitation can become oneself;). Another limitation is the side effects. It's not about opening or closing the diaphragm and that's it. It has consequences. If you know something about the triangle of light, you 'll know which ones. If not, I'll tell you. 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. But this is another issue. But I had to tell you, don't get frustrated if you don't get the expected results! The triangle of light is a concept that you must handle 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 approach. You are interested to know that the same depth of field is not usually achieved behind the plane of focus. Normally behind the focused plane there will be greater depth of field. If you want to achieve the same depth of field ahead as behind, you will have to approach the focus subject. In this graphic I think you'll see it clearer. 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 is focused (the yellow area is the one that is focused). Therefore, a trick to achieve greater blur is to approach the subject;). Here you may see it even clearer. The shaded area is the area that will result in focus.

Subject to 5 meters

Subject to 10 meters

FOCAL DISTANCE

At this point I understand that you know what the focal length is, otherwise, pause and go to this article. Now that you know (or knew) what it was, we continue;). The focal length you use also affects the depth of field. This is the relationship, taking into account the same focus distance, aperture, etc. :

A greater focal length (eg 200 mm) ? lower depth of field
At a shorter focal length (eg 35mm) ? greater depth of field

This is one of the reasons why large angles are more suitable for landscape photography, as they achieve greater depth of field or focused area.

CIRCLE OF CONFUSION

First of all, you should know that the circle of confusion is normally predetermined in the calculators for common parameters. As maximum extensions 20x25cm, viewing distance 25cm and a visual acuity "standard." Now, you are interested in knowing this value if you want to make much larger extensions and control very well which parts are focused and which are not. Now to the subject, the circle of confusion is the maximum size that should have a blurry point in the image 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 seen and the print size. And how do you know what its value is? Here is a calculator:

Circle of Confusion (CoC)	0.030 mm

Also available in the PhotoPillsapp

Embed it in your website

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.

DOES THE SENSOR SIZE HAVE ANYTHING TO DO WITH DEPTH OF FIELD?

Yes, they are related. The larger the sensor, at the same distance, opening ... the depth of field is smaller. And therefore, the smaller the sensor, the greater the depth of field.

DEPTH OF FIELD SIMULATOR

To see all these concepts clearer and without moving from the chair, I tell you a secret, there are what are called photographic simulators and there is one, specifically, that comes to you from 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 are clear, write on your agenda the next outing to practice it with your camera!

IN SHORT, HOW TO GET MORE OR LESS DEPTH OF FIELD?

Get a greater depth of field (more clear area):

With more closed or small openings (between f / 8 and f / 22)
Short focal lengths (10-35mm)
Longer focus distance (moving away)
With smaller camera sensors (with clipping factor) or what is the same, cameras that are not full-format or Full Frame)
Using hyperfocal distance (in another section we will see its importance)
With the edition. Sometimes, we don't have light to close the diaphragm enough or we have to shoot at a very fast speed because it is a moving scene. If you combine several images with shallow depth of field in the editor with the focus on the different planes, you can achieve an image with a greater depth of field

Get a lower depth of field (more unfocused area):

Large or open openings (f / 1.4, f / 3.5)
Long focal distances (70-400mm)
Focusing from a smaller distance (approach the object you want to focus on)
With full-frame camera sensors

This does not mean that you have to meet each and every one of the points, but that each of them will help you achieve a greater or lesser depth of field. For example, we return to the objective of the kit, you want a small depth of field to make a portrait with the background out of focus. I will give as an example my objective which is an 18-55mm f / 3.5-5.6. To achieve a greater blur you would have to:

Approach the subject
Move the subject away from the background (this we have not said) but the farther it is 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, that being the focal length of 55mm the maximum aperture is f / 5.6 (f / 3.5 would be for a focal length of 18mm)
If I could choose between a full-format camera or a camera with a cropping factor, I would use the first one, as I can't because I keep the one I have

As you can see, some of these tricks can help you achieve a greater blur with the objective of the kit;). Sign them up well!

AND WHAT DOES HYPERFOCAL DISTANCE HAVE TO DO? WHAT IS IT FOR?

This concept will help you to photograph landscapes or stars, especially with short focal lengths (10-35mm). It will help you achieve maximum depth of field. To calculate it there are tables and calculators. Here you have all the extended information. But before continuing, I leave you with a trick: when you have the hyperfocal distance, move on, focus at a distance somewhat greater than what you have calculated. If you do not arrive, even for a very short time, what remains on the horizon will be out of focus. Better to spend, so you say;). 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, it is online, or this one . With it you can calculate the necessary adjustments to achieve the level of sharpness you want. Other free applications:

Android: DOF
Iphone: SetMyCamera

Be careful: these calculators will not help you when calculating the depth of field in macro photography . Best test with this specific calculator for macro. Practice

It won't help you to have reached the end of the article if you don't put into practice anything you've read. Go to the simulator, upset it until you have it very clear in your head. Then put it into practice. This is how you learn. Reading is the first step of the way. The goal is reached on foot;). If you found it useful, please share it, maybe we can clarify any doubt to any of your contacts. And if there is something that has not been clear to you, do not hesitate, leave your comment below and we will try to clarify it. Thanks and see you soon!