(Auto) Exposure Bracketing & HDR Explained
Using Auto Exposure Bracketing (AEB) is a simple method of taking photos in different lighting. Once you master the AEB technique, it enables you to shoot High Dynamic Range (HDR) photos faster.
The idea behind HDR photography is to capture the pixels of an image at different points of brightness (e.g., standard light, less light, more light).
The histogram on your camera shows you the brightness scale. The left side of the histogram represents black and the right white.
Let us look at what auto exposure bracketing is and how to use bracketing for HDR photography.
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What is Auto Exposure Bracketing
Auto exposure bracketing is a feature in advanced cameras that help while taking photos in a tricky lighting environment. When the AEB mode is selected, you can take three (or 5, 7, or more) shots at different exposures without having to change the settings manually between the shots.
Besides, the camera chooses one exposure based on approximated metering, it then takes one shot on both sides, which is the overexposed and underexposed. This results in capturing three images at a go, with similar compositions, but at different exposures.
If you set-up the camera in burst mode, the three shots are taken when you hold down the shutter. On the other hand, if you are in the single mode, the shots are taken as you press the shutter three times.
Digital cameras have a different mechanism for selecting AEB. For instance, in the Nikon D70, Automatic Exposure Bracketing is accessed through a button on the bark marked BKT, while others such as Canon, have its settings on the menu.
To see how AEB works on your digital camera you can check your manual and you can also visit this list of auto exposure bracketing settings by camera model.
To have more control while you are in the AEB mode, you can use either the Shutter Priority Mode or Aperture Priority Mode.
- While using Shutter Priority Mode, you will keep the shutter speed at the speed you choose, hence, enable the camera to vary the exposure by changing your shot’s aperture.
- Alternatively, when using AEB in Aperture Priority Mode, you can use the Aperture of your choice hence make variations in shots as per shutter speed.
Auto Exposure Bracketing for HDR Photography
The Set Up
Before you start setting up your camera, identify the final composition. Explore your subject and choose the right framing, distance, and angle. The frame and light will act as the basis for measuring your auto exposure series.
In case you change the composition in the middle of the shoot, you will have to set up your camera and measure the exposures again. Moreover, if shooting from a tripod, secure the camera on the tripod, and compose the shot.
You can watch this video to see how Auto Exposure Bracketing works on a Canon DSLR:
Switching from Auto to Aperture Priority Mode to get Better Images for High Dynamic Range Photos (HDR)
For the best HDR results (sometimes Auto Exposure Bracketing won’t do the trick) you should produce the exposures in aperture priority mode.
Follow these steps for the optimal High Dynamic Range (HDR) Photo:
- Put your camera into aperture priority mode and select the right aperture depending on the scene lighting and depth of field you aim to accomplish.
- Choose a low ISO to avoid noise in your photos.
- Put the camera into a single-point focus mode so that you can manually select the point to use and measure exposure.
- Switch auto-focus off, so that the same subject will remain in focus in all your shots.
- Next, put the camera in a spot metering mode whereby only a small section around the active focus point is used in the exposure measuring.
- Finally use the bracketing function and select -/+ 2 “stops” and select the burst mode (click once, shoot all the three images).
- Optional but recommended: Select RAW (not JPEG) as you image format for more editing possibilities later on when using a HDR Software.
So now you have at least three image values at short, long, and average shutter speed at a fixed aperture, acceptable ISO, and fixed manual focus point.
Taking the Shots
We recommend you use a remote control to avoid camera shake. Push the shutter button and the button, and the camera automatically begins shooting the darkest area, followed by the regular exposure and ends at the brightest area.
Equipment Required While Bracketing for HDR
- A good and sturdy tripod: When shooting brackets a great tripod is compulsory. Also, a tripod that has a remote trigger enables you to maintain perfect alignment between exposures in your series.
- A professional camera body: a camera does not have to be the most expensive, but it should be capable of shooting full frames and have a sensor that can well adapt to low-light situations.
- A wide-angle lens: the difference between a professional and a non-professional photo is the lens. A wide-angle lens allows you capture a whole room or landscape in a single frame.
Related Post: The Best Extreme Wide Angle Lenses
Final Thoughts and Recommendations
In conclusion, Exposure Bracketing (used in Aperture Priority mode) is a great setting to use for HDR photography.
The main issues when taking HDR pictures is the risk of camera movement, as you push the shutter to take a shot. That is why you need a stable tripod. Furthermore, you can use a remote shutter release or self-timer on the camera.