High Dynamic Range
August 5, 2011

Since I am not a particularly avid post-processing photographer, I had little interest in learning new techniques to add creativity to images afterward. My goal is realism, at least in terms of what I consider reality. Since this is how I experience nature, I would like to portray my images authentically to give my viewers the same exposure.

It is probably misguided to avoid exploring different methods of post-processing even if I do not apply it at anytime. In catching up with the latest trends, I stumbled upon a technique called high dynamic range, or HDR, that has been in use for a few years. Within this greater range, more detail can be recorded for use in post-processing. The resulting image can be adjusted to fit a few distinct styles: a highly saturated photograph, artistic and monochromatic depictions, and photorealistic and surrealistic impressions.

For me, I would prefer to gear the images to the photorealistic side and predominately test HDR's ability to produce a "realistic" image. The main benefit to HDR is its ability to moderate relative brightnesses. For example, if the interior of a room is photographed with sunlight flowing through open windows, there are two possible exposures. The first is through metering an object of the room, which would appear much darker than the windows. Thus, the image would show the room correctly exposed but with washed out windows. The second is to meter on the window instead. This creates an opposite effect, and darkens the entire room. Although this problem is unnoticed in observations through the naked eye, the camera's sensor is unable to calculate such a wide range of values for a single image. However, with HDR an array of exposures can be combined to extend the dynamic range and average the exposure for both the window and the room. It is good to note that the solution to this issue of varying exposures can be fixed photographically. One way is to use and off-camera network of flashes or studio lighting to correctly expose the room to the camera's interpretation of the bright outdoor light. Another method would be to use an in-camera overlay system of bracketed shots to moderate the overall exposure.

To illustrate the effects of HDR, I have prepared two images from La Jolla Cove. The first is more photorealistic, with moderated exposures and denser details. Brown pelican roosts and the sandy western gulls' sandy cliffs are all brighter than in a standard non-bracketed photograph. I could have formed a better bracketed set if I had paid closer attention to the quickly setting sun.

The second image is a bit more surrealistic. With high sharpening and basically intense fill lighting, this image features an across-the-board brightening while maintaining the dark mood. The clearest error in this HDR example is the bright whitening between sky and mountain near the middle of the image. One further note: the small gray fledged western gulls in this image are the same ones seen earlier last month, but now with darker plumages.