Tutorial: How to Shoot HDR Images

Posted by Gary Ramey on November 26th, 2012

17th Street Causeway Bridge (HDR)HDR (High Dynamic Range) emphasizes texture and color. It has become extremely popular for landscapes and cityscapes but is also used for food and sports photography. HDR images of food look delicious and the essential oils glissen. For sports such as body building, every muscle and vein pops off the page. HDR images actually have greater color depth than a standard digital photograph. This is accomplished by combining photographs taken with different exposures. To understand how this works, take a look at the following chart for color depth:

Color Depth of Digital Images
Bits Per Channel Channels Colors Per Channel Bit Depth of Image Number of Possible Colors for the Image
1 bit 1 2 1 bit 2 colors (0 or 1 = Black or White)
4 bit 1 16 4 bits 16 colors
8 bit 1 256 8 bits 256 colors
8 bit 3 256 24 bit 16.7 million colors (16,777,216)
12 bit 3 4096 36 bit 68.7 billion colors (DSLR) (68,719,476,736)
14 bit 3 16,384 42 bit 4.4 trillion (DSLR) (4,398,046,511,104)
16 bit 3 65,536 48 bit 281 trillion (HDR) (281,474,976,710,656)
32 bit 3 4,294,967,296 96 bit 79 octillion (HDR) (79,228,162,514,264,300,
000,000,000,000)

Morikami (HDR)The average DSLR has a color depth of 12 or 14 bits per channel which converts to 36 and 42 bit images respectively. That is a lot of color information but an HDR image contains even more color depth because it combines the color information from multiple exposures and exists in a larger color space. Depending on the software used, an HDR image can be saved with 8, 16, or 32 bits per channel.

The programs used to merge the exposures together should be able to align handheld shots but I have found that they are not always successful therefore I suggest using a tripod and a remote shutter release when shooting HDR. The image on the left was handheld. The shutter speeds were fast because it was a relatively sunny day, therefore the resulting photographs were sharp and the software was able to successfully align them.

Three Easy Steps to Shooting HDR

  1. Turn on bracketing
  2. Depending on the subject, separate the shots by 1 – 3 stops
  3. Turn on continuous shooting (burst) mode

Bracketing changes just the speed of each exposure. If you decide change your exposures manually, be sure to only change shutter speed. Don’t change the aperture because that will change the depth of field for each shot and the software that you use to merge the exposures together probably won’t work. If you have a smartphone, I suggest using PhotoBuddy to determine your shutter speeds. It can even let you know which shutter speed to use when shooting more than three shots.

The typical landscape may require five or more exposures because the sky can be ten times brighter than the land. You can still use bracketing but you will need to take several sets of exposures. This is where PhotoBuddy shines. It can let you know what base shutterspeed to use for each set of exposures.
Give HDR a try. You might get hooked.

Read more posts about HDR

 

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