The importance of getting the right exposure for the image one is trying to make, at the time one takes a photo perhaps receives less attention in the digital age than it should; after all there is post processing. To understand more about the subject area, a useful reference book is Michael Freeman’s, The Photographer’s Exposure Field Guide: The Essential Guide to getting the Perfect Exposure; any subject, anywhere.
Freeman explains the importance of making the desired exposure in camera: ‘Getting the perfect exposure means rising above total reliance on the camera’s metering mode, whichever that is. As the first and all-important step is to know what you want from an image, you have to evaluate the exposure before committing to a metering mode, whether this takes a fraction of a second or it’s something you decide at the beginning of a shoot.’ (loc 809). It is easy to let the camera take care of exposure in an automatic mode and end up with an average exposure across the scene. However, this does not necessarily place the key tones in the scene at the tonal level that best suits our intention. Adjustments can be made in post-processing, but there are limits to what can be done without affecting the image quality and disturbing the original, natural graduation of tones throughout the image.
In my own practice, I have tended to rely unthinkingly on the camera’s automatic exposure readings and adjustments too frequently. Freeman emphasises, ‘know clearly what the photograph is about—what caught your eye, what attracts you about the shot, and what you want to convey. Have in your mind’s eye how bright it should be overall, and how the distribution of brightness should look. Naturally, this is the million-dollar question.’ This involves working with the camera’s assumption that the scene should be an average 50% brightness (‘18% grey), where the human visual system perceives the most detail. It involves deciding where key tones in a photograph should sit in relation to 50% and adjusting exposure to achieve a vision.
With high dynamic range scenes (the range between the darkest and lightest elements), Freeman reminds us that there needs to be a compromise or reframing of this kind of scene as it is likely to beyond the range of the camera’s sensor. Or alternatively, take different exposures and blend in post-production. With lower dynamic range scenes, there is more freedom to choose and, in fact, average exposure reading across the whole scene can work well.
Before moving on to look at an example, there are a couple more valuable extracts from the book. Freeman refers to another book, ‘The title In Praise of Shadows is stolen from an influential essay by junichiro Tanizaki, written in the 1930s. In it he railed against the new tendency to install tungsten lighting in traditionally dark Japanese interiors, but the point is not completely alien to photography. In digital processing there is a tendency to choose auto—with its generic brightness—without thinking; but it doesn’t have to be that way.’ It is perhaps this averageness that gives the impression of sameness across much digital imagery, lacking richness in tone. Freeman makes the following important point about human perception, ‘Highlights carry a sense of glare, while shadows are areas we tend to peer into. This is a perceptual matter: if the highlights are rendered so that we think of them as bright, we take them in but tend not to spend time on them; with shadows, if we think they have some relevance we look longer at them to discover detail’. If everything is average brightness, there is nothing to peer into and create visual tension, everything is served to us on a plate.
In this example of a shadowy scene on a river bank, there is a clear highlight area on the grass bank. This is a similar brightness to the edge lighting on the old flood gate mechanism. If I’d taken a photo using an average exposure across the scene, The image would appear similar to the first image adjusted in Lightroom with ‘autoexposure’; the large
shadow areas raised to an average and the detail revealed in a flat-looking image, with highlight details lost.
In contrast, the featured image has (in my view) more interest and a greater depth and richness of tone. It shows the large blocks of shade and the light highlights I’d envisioned.This was taken by spot metering the exposure for the bright area of grass, with a +1 stop adjustment to raise it above the 50% brightness level.
In conclusion, I will be paying much more attention to my vision of exposure in my practice going forward. Perhaps this is just the progression that comes with becoming more familiar and practiced with the camera as a tool for making photos.
Freeman, M. (2011). The Photographer’s Exposure Field Guide: The Essential Guide to getting the Perfect Exposure; any subject, anywhere [Kindle iOS version]. Retrieved from Amazon.com