Bushfire charred trees and snow, a classic example of how the camera's light meter can be fooled. Taking a break from the India photos, today I thought I’d go back into my archives. The “ashes and snow” photographs shown here were taken back in August last year, 6 months after the bushfires of February, 2009, which devastated vast areas of the state of Victoria and obliterated several towns leaving 173 people dead. The bush has a remarkable ability to recover post bushfires and within a few months many charred trees show a profusion of new growth. Indeed the Australian bush has evolved with fire and many plant species actually rely on fire as a means of germinating seeds.
Lots of snow on the ground presents a classic problem for the camera's auto exposure system. For all the advances in digital photography, the light metering system today is fundamentally the same as it was 40 years ago. The camera is programmed to assume that the entire world is 18% grey. This works well on a bright sunny day with plenty of foliage, grass etc in the scene, or it's a portrait with Caucasian skin tones, but where a scene is dominated by large areas of deep black or bright white the system struggles. Time and again I see people posting pictures of snow scenes to social media where the snow is grey. These images are taken straight out of the camera without processing, perhaps the photographer doesn't understand the exposure compensation capabilities of his camera and has little interest nor understanding of image processing.
Whilst digital processing allows us to alter the exposure after the event, increasing exposure in this way runs the risk of introducing unacceptable noise.
The histogram is our friend! By biasing the histogram to the right, exposing to the right (ETTR), we capture as much information (or signal) as possible in the digital file. The amount of noise present in the file will be the similar but less noticeable due to the higher signal to noise ratio.
**** Updated 19.11.16. For a detailed explanation on ETTR and optimal digital exposure try https://luminous-landscape.com/optimizing-exposure/ Note, Luminous Landscape is a paid membership site however, membership is inexpensive and offers a wealth of informative material. **** ~KD