How To Setup Automatic Exposure Bracketing (AEB)

I wrote a blog about the exposure compensation and bracketing last month where I talked about the exposure compensation, when to use it and what does the bracketing mean? In this blog, I am going to talk about the Automatic Exposure Bracketing (AEB) and how to set the controls to activate the exposure bracketing feature for the Nikon D90 or any other DSLR in that matter although the menu settings and the controls might be in different places for a different camera. Sometimes, manually bracketing and taking multiple shots will be forgetful and tedious job. And that is the main reason we use Automatic Exposure Bracketing (AEB) feature available in most of the advance DSLRs. When AEB is activated, camera will take three (or more depending on the camera model and the settings applied) shots automatically provided that you are in a continuous shooting mode or a burst shooting mode. Once the automatic bracketing is activated, when you press the shutter release button once, it takes the first picture at the camera measured exposure, second picture with a negative exposure compensation (usually -1/3 EV but Nikon D90 allows you to specify a different value), and the third with a positive exposure compensation (usually +1/3 EV).

How to set Nikon D90 for AEB?

Nikon D90 Bracketing Menu

1. Press the Menu button on the left side of your camera.

2. Navigate to the Custom Settings Menu (Pencil icon).

3. Go to e bracketing/flash menu and option e4 is for setting up Auto Bracketing with different options.

4. Inside auto bracketing, you have other options available as well to set for but Automatic Exposure (AE) is what we are discussing here.

You can also set the order of how you would want your camera to take the pictures whether it is in the order of correct exposure first, under exposure second and over exposure at last or under exposure first, correct exposure second and over exposure is at third. In order to set that order, you have to go to e6 Bracketing order menu under e bracketing/flash menu and set whichever order you want. This doesn't make any difference on the exposure but just the order in which photographs will be taken and saved in the memory.

Nikon D90 Bracketing Button

Now the next step is to set the exposure value and the number of frames you would want. Nikon D90 allows you to shoot 2 frames over exposed and one correctly exposed (+2F) or 2 frame under exposed and one correctly exposed (-2F) or traditional 3F which gives one under exposed, one correctly exposed and one over exposed picture. So the maximum number of frames for Nikon D90 is 3. In order to setup +2F, -2F or 3F, press the BKT button on the left side of the camera, just below the flash button, and once the button is pressed, you will see an option displayed on the top LCD near the shutter release button to set the exposure value and the number of frames. While pressing the bracketing button, rotate the main command dial to change the number of frames whether it is +2F, -2F or 3F and use the sub command dial to change how much you want to shift the exposure value for the under and the over exposed photographs. Once you are done with all those setup, your camera is ready to take the bracketed shots.

Automatic Exposure Bracketing is a great feature if you want to blend multiple exposure shots and extract the details and the shadows by creating an HDR (High Dynamic Range) image. This technique is getting increasingly popular in landscape photography and I use it almost every time when I shoot night cityscapes .

What Is An Exposure Compensation - Understanding Bracketing

What is an Exposure Compensation?

Exposure Compensation is one of the great features available in modern DSLR camera that allows you to adjust the exposure measured by its light meter. The range of adjustment depends upon the camera model. In case of Nikon D90, this range goes from -5 EV to +5 EV in increments of 1/3 or 1/2 EV where EV stands for Exposure Value.

This means that you can adjust the exposure measured by the light meter by telling the camera to allow more light in (positive exposure compensation, +EV) or to allow less light in (negative exposure compensation, -EV). Depending on how your digital camera deals with the exposure compensation and the shooting mode used, it may adjust the aperture while maintaining the shutter speed constant; it may adjust the shutter speed while maintaining the aperture constant; or, it may adjust both aperture and the shutter speed.

Let's look at these couple of photographs and see the effect of the positive exposure compensation.

At Normal condition (Without applying Exposure)

After applying Positive Exposure Value (+0.7 EV)

What is an Exposure Bracketing?

Exposure bracketing is a technique to make sure that the pictures are properly exposed under challenging lighting condition. Most of the times camera's sensor will automatically set the exposure setting by selecting an aperture and/or shutter speed combination to give the best result. But it doesn't work all the time. Sometime you may want to set the exposure manually overriding shutter speed or aperture settings depending on which shooting mode you are in.

Exposure bracketing technique allows you to take two (or more depending on camera model) pictures: one slightly under-exposed (e.g. -1/3 EV), and the second one slightly over-exposed (e.g. +1/3EV). This range of an adjustment vary with the camera's light meter. I believe it goes from -5 EV to +5 EV with 1/3, 1/2, 2/3, 1 or 2 EV range in case of Nikon D90.

When should we use Exposure Bracketing?

Whenever there is a complex situation of lighting, you should use this feature to get the proper result. Some photographers don't like to use this feature at all. They prefer to look at LCD and take another shot if they are not satisfied with their shot.

But the main reason we do this is to adjust the proper lighting condition over the main subject. Sometime camera's sensor gets confused by the light (too much or too little) to the main subject and hence the subject may be over-exposed or under-exposed. Taking three shots with the variation of exposure is good idea in this case. That is why we use bracketing.

As an example, you can see my above picture that I took under the normal condition. But it came out dark. Then I applied positive exposure compensation and got the balanced result.

Another example would be, lets say you are shooting portrait in snowy area. Your camera meter will adjust the exposure with the surrounding amount of light coming from the snow. In this case, camera senses more light and hence adjust an aperture (small aperture number) or the shutter speed (faster shutter speed) to compensate for the overall exposure. When you take the picture in this case, your main subject will be under-exposed. To fix this problem, you may want to set the exposure value to +EV to properly expose the subject and as a result, your background or surrounding might be over-exposed little bit. You have to calculate proper EV value to adjust this trade off between subject and background lighting in given situation.

Today's almost every DSLR camera allows you to shoot with different exposure value using automatic bracketing feature. If you are using Nikon D90, you can check my blog on Automatic Exposure Bracketing (AEB) where I explained how to setup the camera controls for Nikon D90.