Exposure Bracketing

Introduction

Exposure bracketing is simply the process of taking multiple photographs of a single scene, each with a different exposure setting - some with more exposure and some with less. This can be useful for two main reasons.

  • If you are unsure of the correct exposure then taking a range of exposures around where you think is right should guarantee that one of them will be spot on.

  • If you are photographing a scene with very high dynamic range then you can use post processing to create blended exposures or high dynamic range images, using the best exposed portions of each photograph in the bracketed sequence.

All medium to high-end digital cameras offer exposure bracketing as a standard feature but you can also take bracketed exposure manually using exposure compensation on lower end models.

The only setup involved is to enable the bracketing mode and choose how large the shift in exposure should be between each shot.

Example

Here is an example of an image where exposure bracketing would have been useful as it has a very high dynamic range:

Too-much-range

No single exposure could capture both the highlights (sky area) and the shadows (rocky area) without using a filter in front of the lens to bring the sky down in brightness.

Here is another example of a similar shot, this time using bracketed exposures:

Bracket-normal Bracket-under Bracket-over

What we have ended up with is three separate photographs, each at a different exposure. The first is at the default camera calculated exposure, the second was taken with less exposure - helping to stop the sky from blowing out - and the third was taken with more exposure - helping to to pull some detail out of the darker foreground.

If we wanted to we could then combine a number of these images using either a blended exposure or high dynamic range processing to pull all of this new detail into a single image.

Conclusion

With digital cameras you really have nothing to loose from using bracketed exposures as and when you see fit. High capacity digital storage cards mean you rarely need to worry about the memory used up by the extra shots and you can discard the unwanted ones quickly once on the computer.

The bottom line is that if you are unsure about the exposure for a shot or feel that there might be too much dynamic range, take a bracketed sequence.