Photography News Issue 39

Technique 48

Photography News | Issue 39 | absolutephoto.com

“The histogram does not show where the image is clipping however, so the flashing highlight indicator function serves as a warning that highlights are being clipped and where. Typically in night photographs, highlight clipping occurs when light sources are included. In this case, clipping is usually unavoidable. Highlight detail in light bulbs is not particularly important, but the blinkies will show if there is also clipping in the areas surrounding the light sources. If there is, you will probably want to reduce the exposure to preserve detail in this part of the image.” White-balance “Mixed lighting is one of the things that creates so much potential in night photography, but it can also cause some of the biggest headaches. Digital cameras have awhite-balance function that is generally set for the dominant light source in a scene. White-balance can also be refined with Raw processing software in post-production, but it is best to set the white- balance in-cameraas thewhite-balance setting will affect the exposure histogram, which is

your primary means of determining exposure in many situations. Therefore, setting the white-balance to a colour temperature that renders colours close to the way that you want them will also ensure a better exposure histogram. The AWB setting works well in most natural and artificial light situations, but when multiple light sources are present, the AWB setting averages all of the light in a scene, which does not truly correct for any of the light sources. In situations where the multiple sources are separated in different parts of the image, it may be preferable to balance for one of them alone.” Set image quality to Raw To produce the highest quality images, you’ll need to set your camera to save Raw files rather than JPEGs. Raw files preserve all of the image data that the camera records and it allows for more flexibility when the image is processed. Simply put, Raw files contain more data, aremoremalleable and provide the photographer with more flexibility, especially to bring out shadow detail.

To produce the highest quality images, you’ll need to set your camera to save Raw files rather than JPEGs... Raw files preserve all of the image data... ” Right Contrabando Movie Set, Lajitas, TX, by Scott Martin. Increasing exposure for a right-biased histogram improves quality; when developed the image histograms look similar, but full magnification (top) shows lots more noise after the darker images is ‘pushed’ in Lightroom.

Far left Kathy’s Kosmic Kowgirl Kafe, Terlingua, TX. A 4min, f/8, ISO 100 final exposure compared with a 4sec, f/8, ISO 6400 test. “High ISO test shots allowed me to fine-tune the composition and exposure before committing to a long exposure,” explains Lance.

#5 Paint with light

About the book

& the author

Above Exposure changes have a pronounced effect when light painting. Left: a high ISO ambient-only exposure, 8secs, f/5.6, ISO 6400; middle: long exposure with light painting, 1min, f/5.6, ISO 100. Right: 4mins and f/5.6, at ISO 100 with painting.

In several of the book’s chapters, Lance examines light painting, both in terms of emphasing a particular part of an image, and also drawing with light in the scene itself to formpatterns and light trails: “By using supplementary lighting,” he says “the photographer has greater control over how the image is interpreted by the viewer. Some well-placed lighting can change the feeling of an image and shift the emphasis to different parts of a scene.” Light painting and exposure “Light painting and drawing are inexact sciences and determining the right amount of light to use involves some trial and error. The most important concept to understand when working with added light is that time is used to control the ambient or overall exposure, and the intensity of any added light is largely determined by changing the aperture or ISO. “One of the most challenging parts of this type of photography can be finding the right balance between ambient and added light. If your exposure is too long, the background may look like daylight, and the light painting may be washed out or overpowered by the ambient exposure. If your base exposure is too short, you may end up with clipped or underexposed shadows and light painting that stands out too much from the background. “Consider reducing the time of your ambient exposure by one to three stops if you are adding a significant amount of light. The reason for the shorter exposure is not because the light painting will necessarily affect the background brightness but to ensure a better contrast ratio between ambient and added light parts of the image. How much light to add “There are several factors to consider when trying to determine how much and which type of light to add to an image. In addition to the

ISO and working aperture, you’ll need to consider the brightness of your light source, the distance from the light to the subject, the size of the object(s) to be lit, the reflectivity of your subject, the desired quality of light on the subject, and what colour light will help you to achieve the look you want for the photograph. “The intensity of your light source in combination with aperture and ISO probably has the greatest impact on the image. It is fairly obvious that you’ll need to paint with a pen torch for a much longer time than a big, powerful torch and that a flash set to full power will light a larger area from a farther distance than one set to 1/4 power. Additionally, the same amount of added light will appear brighter with a wider aperture, or higher ISO, than with the lens stopped down, or at native ISO. “Flashguns will maintain their intensity as batteries begin towear out, but recharging between flashes takes longer as the batteries get weaker. Conversely, most torches become dimmer as the batteries are drained, and incandescent lights become warmer in colour. “Another consideration is the distance from the light source to the subject. When a light is moved further from an object, the amount of light reaching the object will decrease by the square of the inverse of that distance. For example, doubling the distance from light to subject will result in only 1/4 of the light reaching the subject (the inverse square law). “If the light starts out six feet from an object and is then moved to 12 feet from the object, only 1/4 of the light (two stops less) falling on the object at six feet will reach it at 12 feet. “Tripling the distance results in the light being only 1/8 as bright, quadrupling the distance results in the light being only 1/16 as bright, and so on. The inverse square law applies to any type of light source. Remember that if the light is reduced by half, the exposure will need to be increased by one stop.”

Lance Keimig has nearly 30 years of experience in photographing at night and has taught the subject since 1998 at venues including the New England School of Photography, the School of the Museum of Fine Arts in Boston, and the School of Visual Art in New York. He teaches workshops around the US, leads night photography tours and lectures around the world. All of that experience is evident in his fastidious approach to Night Photography and Light Painting: Finding Your Way in the Dark , which not only includes a comprehensive technical guide to the subject, and many wonderful images and practical comparison shots (as seen here), but also kicks off with a neat history of light painting since the early days of photography. Published by Focal Press, the book is now in its second edition and spans 268 pages costing £21.99.

focalpress.com