Practical Artistry: Light & Exposure for Digital Photographers
by Harold Davis
By Ron Eggers
Harold Davis’ “Light & Exposure for Digital Photographers” blends the techniques of traditional photography with the tools of digital imaging. As Davis says, “In recent years, the art and craft of photography has changed beyond recognition. Today's photographer is one part digital artist and one part photographer. This book aims to present the best practices of the craft of photography in the context of the digital era.”
While there are numerous books on the market that cover the fundamentals of photography, most of them were written for analog photography. Davis explains what remains constant, and he covers what's changed with digital imaging.
One of his early points is that photographers don't concentrate on the fundamentals of light and exposure as strongly as they should. There's the misconception that, since it’s digital, exposure problems can be fixed in software. It is possible to correct some exposure problems with digital editing, but, he points out, imaging software is best used as a creative tool to improve already good photos rather than to try to save marginal ones.
This book is both helpful and an easy read. You’ll get the most out of it if you start at the beginning and work you way through. It's also educational just to leaf through the pages and read some of the extended captions that go along with full-page illustrations.
The six chapters cover the topics Understanding Exposure, Working with Aperture, Selection Shutter Speed, ISO and Noise, Using Light and Digital Darkroom. Davis starts with exposure fundamentals by explaining the exposure equation or exposure triangle of shutter speeds, f-stops and ISO sensitivity. There's some good basic information in that first chapter, but photographers with an understanding of exposure values can move through it rapidly.
The Aperture and Depth of Field section explains how exposure can be used to control depth of field, including such things as the hyperfocal distance and depth of field previews. That's where Davis gets into creative considerations such as the use of selective focus, bokeh and specular highlights. He explains how the use of depth of field can unify a picture or clutter it, how it affects the narrative of each photograph (and every photograph has one), and even when it doesn't make any difference. The section on macro photography in Chapter 2 deserves attention.
Davis begins the chapter by emphasizing that shutter speed controls not speed, but duration. How long the sensor exposed to light. His point is that once you start thinking about it in those terms, it's easier to understand the influence of exposure duration (shutter speed) on an image. Using shutter speed to play with subject motion can create photos that are dynamic, dignified or powerful. Moving the camera intentionally while the camera is open, on the other hand, leans more toward experimental. Like with the aperture setting, there's a variety of information on shutter control and the creative use of subject motion.
This is also the section that covers camera shake and image stabilization. He notes that image stabilization or vibration reduction should be turned on when using a camera with a long telephoto lens, but, in most cases, it should be turned off when using the same camera and lens on a tripod. “IS can actually make tripod shots less steady (unless your camera or lens with IS has a mode specially designed to be used with a tripod).” It would have been helpful if the author went into the reasons for that, since that's an underlying characteristic of image stabilization that's contrary to expectations.
ISO is the third leg of the exposure tripod. Davis explores the relationship between the light sensitivity of the sensor and the characteristic and capture quality of the image. This is a section that deserves a closer look for photographers who shoot digitally and want to improve the technical quality of their photographs. Unfortunately, the text was written before the ultra-high ISO digital SLRs came onto the market, extending as high as ISO 25,600. Experimenting with and exploring such high ISO settings will have to wait for a future revision.
The quality and temperature of light, obviously, also impact exposure. "White balance probably intimidates more photographers than any other digital camera setting," Davis notes, explaining the fundamentals of color temperatures and the need for avoiding colorcasts. But then, unlike with conventional photography, where shooting with the right color temperature film is vital, the importance of the right color temp when shooting digital is repeatedly minimized.
"As a practical matter, I don't worry too much about measuring the color temperature of light. . . I expect to adjust my color temperature on the basis of what looks right, after I have taken my photos." Later he continues, "The white balance setting in your camera doesn't much matter." However, he concedes, "Well, OK, white balance itself does matter. But your initial white balance settings aren't really a big deal (at least if you are shooting RAW.)"
He makes a valid point about being able to adjust white balance when post processing RAW images. While white balance is embedded into JPEG images, it is only a tag in a RAW file. Any white balance setting can be applied to the RAW image in post processing. And that is the way that some photographers prefer to work. But, to me, that seems to go against his earlier point of that it's better to shoot it right than to rely on making adjustments in an image editing program.
The sections on front lighting, side lighting, back lighting, overcast lighting, night photography and flash photography are relatively basic, but they do include tips and techniques to improve those types of photography.
The last chapter, Digital Darkroom, goes into image optimization, digital exposure adjustment, electronic noise reduction, working with RAW files, cross-processing simulation and photo compositing. He repeats the frequent comparison of the RAW file being the negative while the post processes image is the print. That comparison always bothers me. The RAW file is much more versatile than processed film. A comparison I like better is that the original RAW file is the unprocessed film while the post-processed image is the processed film that's used to print an image, since the print is going to be made from the processed file. The advantage of shooting RAW is that, unlike with film, where one processing locks you into the results, if the processed digital film isn't right, it's possible to go back as many times as you need to reprocess it.
Davis touches on a lot of topics in “Light and Exposure for Digital Photographers,” and his images are interesting. However, in order to make the book more applicable for a wider range of photography, he sometimes doesn't go into the depth of detail that would be most beneficial for professional photographers. This is not a book on RAW imaging or using Photoshop, so it's understandable that coverage of some topics is limited, but there are topics, such as RAW conversions, that could have been covered in greater detail.
On the other hand, the book does present a good overview of the numerous topics covered, which could be helpful for any photographer moving into serious digital photography.