HDR Photography Basics

Capela no Mar

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HDR stands for High Dynamic Range and refers to a specific type of photography which combines several exposures of a single image, blended together to make one final picture. HDR is primarily used in situations where the camera is unable to capture the full range of light present in the composition. A perfect example is a clear sunny day in a field. Exposing the field properly will cause the sky to look bright white instead of blue and exposing the sky properly would cause the field to look too dark. By taking multiple exposures, one for the field, one for the sky and one in between, you can blend them together to make an image which exposes each part of the picture perfectly.

Auto Exposure Bracketing
Auto Exposure Bracketing, or AEB is a common feature on many digital cameras. It useful for HDR because it sets up the multiple exposures you need automatically. AEB is available from 3 to 9 stops of exposure bracketing. In other words, you can take 3 different exposures on most cameras and up to 9 exposures on some higher end units. The more exposures you get, the more information you have and the better your picture will turn out. Go into your camera’s settings and turn on AEB for the maximum number of exposures.

Settings
Besides AEB, there are some settings that you should adjust before taking a set of HDR exposures. Use your camera’s highest image quality setting. If your camera is capable of RAW images, use it. Otherwise, use the highest quality jpeg setting. Set the ISO, or film speed, as low as possible. Higher ISOs create noise or grainy images which are only exacerbated by the HDR process.

Gear
To a certain extent, better gear will produce better pictures. A digital SLR camera capable of RAW images is best for HDR photography. However, a good point and shoot will do the trick in a pinch. A tripod is necessary in almost all situations. Because you are blending three different photographs together, each one needs to line up perfectly with the other. Finally, creating HDR images is a fairly computer intensive process. You’ll need plenty of RAM and processing power if you want to make more than one HDR picture a week.

Software
There are lots of programs available that can help you create HDR images. Adobe Photoshop has an HDR feature and gives users more options for final processing tweaks, but it is more expensive and more complicated. For first time HDR users, consider Photomatix. Photomatix provides very simple HDR processing and excellent results. Remember to sharpen, crop and adjust color settings on each image before you make an HDR photo. Once the HDR image is processed, basic adjustments are harder to make.

Processing
Within the HDR world there are very differing views on post-processing. Some photographers enjoy very subtle HDR images that are hard to distinguish from regular photographs. Others find the over-the-top, mutant, radiation, acid-trip look appealing. The main difference between the styles is the gamma and luminosity settings which greatly affect the saturation and light quality.

By Patrick Hutchison

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