WHAT IS DYNAMIC RANGE (AND WHY YOU SHOULD KNOW IT)

Surely more than once you have read something about the dynamic range. It usually appears here and there in any article about exposure , histogram , exposure meters or light in general. But do you really know what it is? Do you know how to get the most out of it? Well, I hope to know how to explain myself well and, that at the end of the article, you are a master of the dynamic range, or at least that you have understood and internalized the concept

WHAT IS DYNAMIC RANGE?

As always we are surrounded by photographic words that get tangled in our fingers, cloud our minds and confuse us, this time, we will leave the definition for later.

Now just think: how many times are you looking at a beautiful scene, of which you like everything, with a magical light, beautiful colors, and you decide to take out your camera to immortalize that essence, that wonderful light, that sky full of infinite shades, frames , expose, shoot and surprise! Photography and the scene have nothing to do. You get burned sky, no shades, or dark earth, no textures. Nothing to do with the wonderful scene in front of you. Didn’t it happen to you millions of times?

Well, that is mainly due to two factors:

  • That happens in the first place, because our eye is infinitely better than a camera (however professional it may be) in capturing simultaneous detail in light and shadow, since it has the ability to continuously adapt the pupil to the different brightness levels of the scene.
  • Secondly, because the scene (although as we are able to process it correctly with the naked eye it may not have seemed like it to us), it has too much difference between the lights and the shadows so that the camera can correctly process both, that is, it has more dynamic range that our camera can capture.
The eye’s ability to capture detail in the lights and shadows is amazing

DYNAMIC RANGE (or Dynamic Range): is the ability to capture detail in the lights and shadows within the same image . That is, our ideal goal is to achieve almost pure blacks and whites with a lot of intermediate values .

THE HUMAN VERSUS THE MACHINE

When we talk about dynamic range, we talk about the ability to capture the different lights and shadows in detail of a scene, right? We usually express this difference in diaphragm steps . The more difference diaphragm steps the camera can express correctly, the better dynamic range it will have. That is, a camera that has a dynamic range of 8 diaphragm steps will be better able to capture the light reality of the scene than one that only has 5 diaphragm steps.

And while our cameras are working, for example, with 5-8 diaphragm steps, our eye is able to process scenes with more than 15 diaphragm steps apart. Almost nothing, isn’t it? That’s why always, always, we must assume that in scenes with a lot of difference between lights and shadows (very contrasted) our camera will be unable to portray what our eyes see.

THE HISTOGRAM, YOUR GREAT ALLY

We talked in his day about the benefits of  histogram , how it can help you see if your image is well exposed or not, but not only that, it can also help you see if your image has a rich or poor dynamic range, and so Therefore, it can help you work in situ to improve it. Let’s see how the different types of dynamic range are translated according to the scene and the histogram in several images:

IMAGE 1:

What can we deduce from the following image by observing the histogram regarding its dynamic range? If you look closely at the histogram, you will see that it contains information throughout the histogram; in the central area as well as at the ends (left shadows, right high lights). This means that from this scene, we have managed to obtain a good dynamic range, since we have information of medium tones, lights and shadows.

IMAGE 2:

What do you think of the following scene? Would you say I have a good dynamic range? If you observe how the information is distributed throughout the histogram, you will see that it contains, like the previous image, information in all the light zones, so we would also say that it has a good dynamic range.

IMAGE 3:

Now look at the following image, would you say it has a good dynamic range? The majority of the information is concentrated in the right part of the scene, corresponding to the white ones and the high lights, but the left zone hardly has information, there is hardly any shadows or blacks, you see it?

IMAGE 4:

Finally look at the following image. What do you think about the dynamic range of the image? Have you noticed how the information of the lights is concentrated in the left area of ​​the histogram? In this case, there is hardly any information about highlights or whites.

HOW TO SQUEEZE THE MAXIMUM DYNAMIC RANGE

Keep in mind, however, that if the scene in front of you does not have a sharp difference between light and shadow , that is, if, for example, your camera supports up to 7 steps of light difference, and the scene only has 5, your Camera will be perfectly capable of portraying what lies ahead . You can do the test by measuring the darkest areas of the scene and then the lightest ones and see how many diaphragm steps of difference there are between them to know if your camera will really be able to accurately portray the scene.

But the essential thing when it comes to achieving the maximum dynamic range that it offers you is to take advantage of it , and that is done simply by  making a correct measurement and exposure of your photographs. That is, there will be scenes that are, naturally, somewhat pasted, or with very high contrasts, which will leave a good part of the scene without light information. No need to worry, there are images that are just like that. Now, of any scene that we want to represent, the important thing is not to fail in the measurement and exposure of the image because if it is well exposed, it will mean that we have achieved the greatest possible dynamic range in situ and that we can then work it in the process to expand something more dynamic range of the scene.

Just don’t forget to shoot in RAW as long as you anticipate that you are going to retouch your images.

TECHNIQUES TO INCREASE DYNAMIC RANGE

FILTERS

There are landscapes so beautiful that it seems that they are going to have to photograph themselves, right? Too bad that when we take the photo, the usual thing happens to us, that the sky has too much light compared to the ground and it turns out that it burns us, or the earth too dark. Now we know that this is the fault of the limited dynamic range of our cameras ;-). Luckily we are not alone in the face of danger. With the help of a neutral density gradient filter , we can help compensate for the two exposures thus reducing the difference between lights and shadows, and helping to widen the dynamic range of the scene by not having to choose between lights or shadows.

Use a degraded filter to compensate for exposure and increase dynamic range

BRACKETING

There are different types of Bracketing (or bracketing), although in this case we will focus on the exhibition. The bracketing exposure is to take several identical images in framing, varying only exposure in each. Normally three images are made, one exposed for the lights, another for the shadows and another one with the “correct” values ​​that the camera provides us. Once we have the images with the different exposure values, we can join them through Photoshop or some other editing program so that all the information overlaps one on top of the other, giving us detail in all areas of the image. For a better explanation click here

WORK RAW FILE

With our “raw” file and the amount of information about lights and shadows it contains, recovering lights is simple and usually gives good results whenever we start from a good image. Working with the basic settings such as shadows, highlights, blacks, whites and even contrast, will allow you to expand the dynamic range of your image satisfactorily.

If you doubt between exposing for the shadows or the lights, do it for the shadows, these are more difficult to recover than the lights, because in doing so they generate a lot of noise. It is what we call to right the histogram , or what is the same, that the image tends more towards the high lights than towards the shadows, so that we can finally recover the image with less loss of quality than in the opposite case.

DEFINITELY

To faithfully represent what surrounds us, so that an image is able to transport us to the scene that existed at the time of making the shot, the closer we get to the original model, the more the viewer of our images will be able to enter that moment. That is why we never recommend abusing touch-ups or HDR, too many touch-ups give a sense of unreality and distance us from the moment we wanted to represent through our image.

I hope you found this article useful, that it has contributed something and, above all, that it has made you go to look for the camera, or open the computer to touch and analyze images, histograms, lights and shadows. You only learn by fiddling and practicing Ah, and don’t forget to share if you think it can be useful for someone else. Thank you and see you soon.


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