High Dynamic Range Imagery and your Photography (Part 1) Temecula, CA

This 2 part article will address High Dynamic Range Imagery known as “HDR” and what one can do with it for fun and profit.

First I think one should understand what HDR is and the best definition I could come up with and was found on “Wikipedia”.

In image processing, computer graphics, and photography, high dynamic range imaging (HDRI or just HDR) is a set of techniques that allow a greater dynamic range of luminance’s between the lightest and darkest areas of an image than standard digital imaging techniques or photographic methods. This wider dynamic range allows HDR images to more accurately represent the wide range of intensity levels found in real scenes, ranging from direct sunlight to faint starlight. The two main sources of HDR imagery are computer renderings and merging of multiple photographs, which in turn are known as low dynamic range (also called standard dynamic range) photographs. Tone mapping techniques, which reduce overall contrast to facilitate display of HDR images on devices with lower dynamic range, can be applied to produce images with preserved or exaggerated local contrast for artistic effect. (Ref Wikipedia)

The above picture was processed as a non-HDR image. As with the same picture on the right is a processed HDR image.

So how is this accomplished in photography and can you do it? Well it depends on the camera you own. No you don’t need a $4,000 camera to do HDR. Some point and shoot cameras and DSLR’s have this feature. But before I get into what cameras do this let me explain how it’s done.

Basically it is a combination of three (3) successive photographs taken at the same subject with different exposure settings. One dark one regular and one overexposed. Depending on the camera you own you can vary these settings to your own liking. Personally I like 2 down and 2 over the automatic exposure setting.

This is known as Automatic Exposure Bracketing (AEB). Many digital cameras include an Auto Exposure Bracketing (AEB) option. When AEB is selected, the camera automatically takes three or more shots with different exposure settings for each frame. Auto Exposure Bracketing is a very useful option for taking HDR scenes. Understand, AEB was not really intended for HDR photography, but rather for ensuring that at least one of the pictures would be as close to perfectly exposed as possible. This is probably why some camera models only make it possible to auto bracket three shots at a maximum of one Exposure Value (EV) step difference or even less. Note, three shots spaced by one EV are often not sufficient for properly taking HDR scenes. This is why it is important to look at the settings of the Auto Exposure Bracketing features of a camera model to determine whether that camera will be convenient for HDR shooting.

The number of frames per second that the camera can take (referred to as "burst rate") is another important factor for HDR shooting The faster the auto-bracketed shots, the less pronounced ghosting and mis-registration problems will be.

Does your camera have the AEB feature and to what EV? Those are 2 very important questions one should research before buying a new camera when you want to be able to take dramatic HDR pictures. In part 2 of this article we will discuss what settings you want to set your AEB (within your cameras limitations) and how to process those images to your desired effect. Now understand HDR imagery can be taken to the ridiculous side, so how and where you apply it is only restricted by your imagination.