Friday, January 27, 2012

Physics band names

Sunday, January 15, 2012

HDR, photojournalism, and Lightroom 4

On his blog, Charles Apple discusses the use of high dynamic range (HDR) images in newspapers. The discussion raises questions about what constitutes excessive manipulation for photojournalism, and in particular what the impact of next-generation photo processing software will be on these definitions. I don’t know, in detail, the prevailing ethical standards of photojournalism, so in part I’m looking for the thoughts of experts on the topic.

Let’s begin by discussing HDR photography. The sensor in a digital camera is only capable of recording a certain range of scene brightness, from dark to light. A part of the scene that falls outside this range will be “clipped” to pure black or white, without detail. To get around this technical limitation, it’s possible to take multiple exposures of the scene, with different exposure settings (e.g. shutter speed). This will allow some of the exposures to record the bright parts of the scene, at the expense of the dark parts, and other exposures to do the opposite. These exposures may then be combined in software, to produce a “high dynamic range” image, whose range of scene intensities surpasses what the sensor can record directly.