Photography News Issue 39

Photography News | Issue 39 | absolutephoto.com

Technique

#3 Master composition and focus

“In many ways” says Lance, “composing a night photograph is no different from daytime images. The rules of design apply equally in the dark as in the light. Compositional devices like the rule of thirds, diagonal lines, and repetition make for dynamic compositions at any hour. “Sometimes though, it may be necessary to modify a composition to exclude bright light sources. Such a modification may be a compromise to the ideal, but if it restricts dynamic range to that of the camera’s capability, it may be justified. Bright areas at the edge of an image always draw the viewer’s attention, and this is particularly true at night… they can lead the eye away from the subject.” Seeing in the dark “Composing and focusing can be difficult in low-light conditions, simply because it is hard to see the image in the viewfinder. Fortunately, there are simple solutions to deal with these problems. Digital cameras afford us the luxury of being able to view the image immediately after capture, so setting your camera to the highest ISO setting and doing a series of handheld test exposures is a good way to refine a shot.“This technique is a great way to predict and correct for potential problems like flare, and also to spot stray objects at the edges of the frame that might have otherwise gone unnoticed. Live view to the rescue “Live view is an extremely useful feature that can be used in combination with a torch to make focusing in darkness more manageable. A bright torch can aid both composing and focusing your night shots. By shining the light around in the image while looking through the viewfinder, it may be easier to find the corners of the frame. Night photographers should pay extra attention to the entire image, both because it can be difficult to see, and because night photographs generally require a greater commitment of your time and energy. It is always disappointing to invest 15 or 20 According to Lance, “extreme contrast and a wide dynamic range are the most challenging obstacles in urban night photography” and there’s a whole chapter in his book dealing with exposure settings to tame these problems, as well as giving lots of detail on white-balance settings and ISO settings for clean and natural-looking results. Contrast and dynamic range “The range between the darkest black and brightest white in a scene, digital file, negative, or print is called dynamic range. The dynamic range between bright and dark areas in artificially lit environments can easily be 15 stops, and if light sources are included in the image that range is greater still. This exposure difference between shadows and highlights is more than any camera sensor can accommodate without going to extreme measures (like HDR processing or exposure blending using layer masks). “Sometimes an image is worth the investment in post-processing time to try to recover a shot with such high contrast, but the best way to handle such extremes is to manage them in-camera whenever possible. A slight adjustment of the composition can often reduce overall contrast… it may be possible to #4 Ace the exposure

minutes in a single exposure only to later find an unnoticed object in the shot that could have been easily avoided with a little more care before pressing the shutter button. “A great technique for determining the edges of your image in a very dark and confined environment, for example inside a building, is to shine your torch through the viewfinder and observe where the light falls. This can be a very useful technique, but it will only work with DSLRs and a very bright torch in a confined space that is almost completely dark. Light up the scene “Just as your torch can be helpful when composing, it’s also a useful for focusing. The most obvious technique is to standbehind the camera and shine the light on the area to be focused. Then focus manually while looking through the viewfinder. “Focusing utilising this technique in conjunction with live view is even better. The live view image may not be bright enough to use for focusing without the aid of a torch, but combining the zoom feature on live view with a bright torch allows for extremely accurate focusing. Canon cameras have a live view mode that simulates how the exposure will look with the camera settings as they are currently set on the camera. You should disable this exposure simulation option as it may darken the image and make it harder to see in most situations.” An optimal exposure Optimal exposure for digital photography pushes the histogram to the right (in a Raw file) where the sensor is tonally rich. Such an exposure will probably appear overly bright straight fromthe camera, but will also have the information necessary to make a quality print. An optimal Raw file contains the maximum possible ratio of image information (signal) to data that is anunwanted by-product of capture and processing (noise). This is known as the signal to noise ratio (SNR) and providing the sensor with the greatest possible exposure without clipping important highlights is the way to ensure the best SNR. Expose to the right “Determining optimal exposure is based on an evaluation of luminosity andRGB histograms, the preview image, the flashing highlight indicator, and analysis of the scene based on experience. There is no such thing as an ideal or perfect histogram… however, a right-biased histogram – one where the bulk of the data is on the right side – is more flexible, and apt to make a better quality print. A great trick for determining the edges of your image... is to shine your flashlight through the viewfinder hide a prominent light source behind a tree, street sign, or an other object in the scene.

Above Green Street, Bodie Ghost Town, CA; a 30sec exposure at f/4.5, ISO 800. Night scenes can be hard for you and your camera to see, but if you’ve taken a torch to illuminate the subject you can use that to help focus and compose, too. Below Gowanus Canal Bridge, Brooklyn, NY. In these 30sec, f/8, ISO 400 exposures, the image on the left shows lens flare from a streetlight just outside the frame; flare was avoided in the right-hand version using a card to shield the lens, but you can also make minor changes to the composition to mask light sources.

Above Deer Island Sewage Treatment Plant, Boston, MA. Both images, shot 20minutes apart used identical exposure (30secs at f/8, ISO 100) and white-balance settings; the difference is caused by the changing ratio of daylight to artificial light, while low clouds are also reflecting the sodium vapour lights, and adding a yellow cast in the second pic. Left Congress Street Bridge, Boston, MA. This shows how the white-balance setting affects the appearance of the exposure histogram. The top image was taken with white-balance set to Shade, the middle manually set to 2500K, and the bottom using the Fluorescent setting. Notice how the blue and red channels change dramatically.