How to make the most of exposure bracketing.

You too may have had to take a photograph in which one area is fully illuminated while the other is in shadow .

Think, for example, of photos taken outdoors in full sunlight. The sky is very bright, while the ground is naturally darker. If you want to expose the ground correctly, the detail in the sky will inevitably be lost.

Another critical situation are the photos taken at home, during the day, with the presence of a window hit by the sun.

In such cases, the difficulty is obvious: you have to expose on the bright side or on the shaded side. Exposing the whole scene correctly is impossible.

It's not a mistake on your part, it's normal. Unfortunately the camera sensor (even the most advanced on the market) has a reduced dynamic range compared to your eyes.

However, technology can help you. You can do exposure bracketing.
It's a technique that allows you to improve the dynamic range of the shot.

In this article I will explain to you:

• what is bracketing for?
• exposure bracketing and HDR
• how bracketing is done
• where bracketing is applied
• bracketing after shooting

What is exposure bracketing for?

As I mentioned above, exposure bracketing allows you to broaden the dynamic range of your shot. I'll be clearer with an example. See the photo below.

This is a typical high-contrast scene. The sky is very bright, while the small port and the houses on the right are more in the shade. When looking for the right exposure you have to make a choice: expose correctly on the sky or on the ground.

If you choose the darkest part, the brightest areas will be overexposed (as above).

Here's a new attempt trying to expose correctly on the sky:

Now the detail of the sky is visible. But here's the flip side: the mainland, more in the shade, has become underexposed.

It is a problem related to the dynamic range, much more extensive in the human eye than any sensor on the market. Dynamic range is the ratio of the brightest to the darkest point in a scene.

If there are brightly lit and dark areas in a scene, the camera sensor struggles to find the happy medium to properly expose each area. The human eye, on the other hand, can do it.

Exposure bracketing allows you to take multiple shots of the same scene at different exposure values. It is also called "bracket exposure" . On the camera menu, in fact, the bracketing function looks just like a fork.

By turning the camera wheel to the right or left you can increase or decrease the range of the fork. For example, if you set the slider to “2”, the camera will take 3 shots: one underexposed by -2 stops, one correctly exposed and one overexposed by 2 stops.

By setting up exposure bracketing, you can choose your preferred exposure when you get home.

Actually, one of the more interesting applications of bracketing is HDR.

With HDR you can "merge" the different photos taken with bracketing, preserving the correctly exposed portion of each one.

The result will be an image with a wide dynamic range. Put simply, you'll get a scene that is correctly exposed in both the brightest and darkest areas.

Taking for example the photos we have seen above (and adding a third one correctly exposed in halftones), the result is this:

Thus we obtain a final image where both the sky and the sea and the ground are correctly exposed. Later I'll explain how to effectively create an HDR with Photoshop.

How is exposure bracketing done?

But how is exposure bracketing achieved in practice? The first step is to take multiple shots by correctly exposing in different areas of the scene. The number of shots must be odd (at least 3, or 5, 7, 9…).

Supposing you want to take 3 shots of a landscape photo, in the first shot you will expose the sky correctly, while in the second you will have to expose using the midtones as a reference. In the third shot, the correct exposure will be taken in the darkest area of the scene.

There are two ways to do this, namely:

• manual bracketing
• Auto Bracketing

The manual method is simply taking 3 (or more) photos of the same scene at different exposures.

Auto bracketing, on the other hand, can be done directly with the camera (if your model allows it). You just need to set the fork stop range , as I showed you above.

The camera will then automatically take multiple shots at the different exposure values set.

If the automatic HDR function exists, the camera software will take care of merging the shots and showing you the final result.

Automatic bracketing, as opposed to manual bracketing, is practical and fast. Working automatically, however, you have no control over the various stages of the process.

How to shoot for bracketing?

You can't apply bracketing in all situations. Here's what you need to watch out for:

• do not change framing during shooting
• choose only static subjects
• do not change the aperture
• use a tripod

I'll explain them to you better, one at a time.

Do not change framing during shooting

Whether you use manual or automatic bracketing, your shots must be identical.

For each shot you will change the exposure, but the scene must be absolutely the same. Otherwise, artifacts will be created during the fusion process. You may get double or distorted images.

Choose only static subjects

For the same reason, there must be no moving subjects in the frame. You would end up with the subject in different positions in the various shots.

This would cause the merge process to fail. The most probable consequence is that of obtaining, again, double images or a “ghost effect”.

Do not change the aperture

This is a common but understandable mistake. When looking for the right exposure, you may be tempted to fiddle with the aperture to let in more or less light.

Closing or opening the aperture, however, also affects the final image. Acting on the diaphragm, in fact, also causes a variation of the depth of field.

What is in focus in one shot, therefore, may be out of focus in another, and vice versa. As I have already explained to you, the image must never change between shots.

To correct the exposure, therefore, act exclusively on times and ISO.

Use a tripod

I have repeated ad nauseam that the image within the frame must never change. If you shoot handheld, getting shots that are all the same becomes a feat.

A tripod will help you keep the camera steady. Alternatively, you can place the camera on a solid surface.

Where is it best to use bracketing?

As I explained to you, exposure bracketing is a great solution for high-contrast scenes.
Consequently, here are the situations in which it is more appropriate to use bracketing:

• landscapes
• architecture
• interior

In the examples below I show you some photos with the final HDR result.

Bracketing in landscape photos

Landscape (daytime) is the situation most prone to high contrast conditions. You will often find yourself dealing with a very bright sky, while the ground will be noticeably darker. In these cases, exposure bracketing can solve many problems for you.

Photo by Mantas Hesthaven

Photo by Robert Lukeman

Photo by Joran Quinten

Bracketing in architectural photos

Architecture photos can be considered a kind of landscape photo.
In this case you may need to correctly expose the architectural structure, but also the sky, to make the photo more balanced.

Photo by Meduana

Photo by JOSHUA COLEMAN

Photo by mostafa meraji

Bracketing in interior photos

In interior photography, you often find yourself photographing rooms that include a window or veranda.

In these cases, you need to properly expose the room. As a result, windows or verandas will always appear severely overexposed. Exposure bracketing solves the problem.

Photo by Matthieu Comoy

Photo by Francesca Tosolini

Photo by Douglas Sheppard

After shooting

After bracketing, if you want to get HDR manually you need to use post-production software. Here I will show you how to do it with Photoshop.

It is a very simple process, because there is a function dedicated specifically to HDR. I'll explain it to you step by step.

Once Photoshop is open, you need to go to File and search for Automate . From here choose the Merge to HDR Pro feature…

At this point a dialog window will open, from which you can choose your files using the Browse button…

When you have selected the 3 shots (or 5 or 7…) at different exposures you took, they will appear in the dialog.

By pressing OK, the software will start acquiring the files. After a few seconds, you will find this screen in front of you.

At the bottom left you will find your 3 shots. Here you again have the option to choose which shots to use for HDR. In the big window, you already have a preview of the final result.

On the right, you will find a series of commands useful for optimizing the fusion. With Tone and Detail and Advanced you can improve the final result. Pressing OK starts the fusion process. Eventually you will get the JPEG file inside Photoshop.

Of course, you can further adjust the file from here. You can adjust the contrast, or open or close the shadows according to your needs.

Conclusions

Exposure bracketing, especially when combined with HDR, is a very powerful tool. This is essentially the only technique capable of increasing the dynamic range of a high-contrast scene.

Be careful, though, not to overdo it. Especially with HDR, it is very easy to go over the size limit and get unreal images, which correspond very little to reality.

Probably you too, from time to time, will have come across scenes like this:

As you can see the result is a bit excessive. The image is very detailed and the overall feel is fake, like graphics.

As an old photographer friend of mine loved to tell me "the best post-production is the one you can't see" . So it's perfectly fine to make an HDR to recover dynamic range. Be careful, however, not to go beyond the limit of the credible.