Travel Photography: Tips and Tricks for High Contrast Scenes
It's summer, time for travelling and also peak season for nature and travel photography. Digital cameras are still getting better and better and easier to use. However, sometimes it is quite disappointing that a picture such as a historic city alley either is partly underexposed with huge dark shadow areas, or the roofs and the sky are extremely overexposed. Although it is possible to review the image immediately in the display on the camera, the problem can often only be addressed at home in the post-processing workflow, and then it might be too late to fix the image in order to get a beautiful photograph.
Many travel and landscape photography pictures have very high contrast. "Dynamic range" is the term for the range of light intensity from the darkest shadows to the brightest highlights and it is measured in "exposure values" (EV), also commonly called "stops". Our eyes are able to adapt to see high contrast scenes but the dynamic range of the sensor of a digital camera is limited. Unfortunately the dynamic range of monitors, photographic paper or print is even more limited. A dynamic range of an image of about 8 to 9 EV is usually no problem. Experienced photographers can handle dynamic ranges of 10 to 11 EV quite well with exact exposure settings and with the help of calibrated monitors. But what about high contrast scenes with a dynamic range of 14 EV and higher? In particular landscape photography offers a wide range of high contrast scenes: idyllic sunsets by the seaside, backlit photography or scenes in high mountain regions.
An important rule in photography is to avoid high contrast in the first place. Many professional landscape photographers shoot only early in the morning or between late afternoon and evening because the light is much softer. Long shadows can be avoided when the sun is at the back of the photographer. Foreground subjects in backlit photography should be placed in front of a dark background because the high contrast can only be recognized as a small light fringe around the foreground subject. Long shadows might be wonderful for creative photography, but the final picture should offer enough details in dark shadow areas as well. The dynamic range of a scene can be simply reviewed with the help of the brightness histogram on the rear screen of the camera or manually calculated with contrast measurement. If the dynamic range of a scene or subject exceeds 10 or 11 EV the photographer should probably try out one of the following approaches.
A classical tool to handle high contrast scenes like alpine mountain ranges is the graduated filter. With the help of the graduated filter the sky can be exposed correctly, but at the same time the foreground gets enough light to avoid underexposure. There are ND gray filters, but also coloured versions of graduated filters with mostly orange or red shades of colors. Graduated filters were very important for analog film photography. Nowadays digital photography offers better technologies like bracketing, HDR or RAW-push and graduated filters are gradually become less important.
Bracketing and HDR are technologies to control high contrast scenes based on successive shots with different exposure settings. HDR images are automatically combined by the camera into one high dynamic range picture. Bracketing (or more precisely: "autobracketing") is a feature where the camera stores several shots separately in order to combine the shots later in the post-processing workflow. HDR often creates pictures with an artificial look and feel, sometimes even with a relief-like result. The autobracketing method is much more time consuming, but on the other hand it delivers excellent results. Advanced cameras offer sophisticated autobracketing features. It is possible to adjust the exposure setting with an accuracy of 1/3 EV and the number of successive shots. A basic setting could be for example three shots with a difference of 1 EV. For the bracketing method a tripod is not necessarily required. The camera should be set to continuous shooting mode (or "burst mode") and the camera automatically handles the settings of the autobracketing (in this example 3 shots with -1/0/+1 EV). In the post-processing workflow the different exposures can be automatically imported and accurately positioned for example in Photoshop as separate layers. The last step is to manually blend the different exposures with the help of appropriate selection tools of the image editing software. The advantage: the photographer has complete control over the high contrast scene and it delivers excellent results. Sometimes if needed even up to 7 different shots with an exposure difference of 1/3 EV. The disadvantages: the method can be very time consuming, and it is not suitable for moving subjects like for example sea surf, trees and strong wind or people and animals in the scene.
RAW Dynamic Range Push processing
Advanced photo sensors of digital cameras offer an extremely wide dynamic range up to almost 15 EV. This incredible dynamic range is possible because these sensors provide a very low noise level and the shadow areas of a picture can be strongly pushed without losing too much image quality. However, this applies only to RAW files, photographers who are using JPEGs cannot benefit from the wide RAW dynamic range of an advanced sensor. The approach is quite simple: the exposure is adjusted to the highlights of the high contrast scene. As a result the shadows of the scenes are underexposed, sometimes even severely underexposed (nearly black). With the help of the RAW converter only the shadows are pushed by up to 4 or 5 EV. The result is a correctly exposed image with detail in the highlight and the shadow areas (comparable with bracketing ...). The advantages: it is a very simple method, no tripod necessary, no bracketing necessary and also moving subjects can be shot based on this approach (which is important especially for wildlife photographers). But there are also disadvantages: the wide dynamic range of almost 15 EV is only available at ISO 100, higher ISO values gradually reduce the available dynamic range. Also the picture on your camera’s viewfinder screen is often very dark, which sometimes means you need to take a control shot with a normal exposure for color corrections later in post-processing. It is also important to know that the shadow areas of the image have a higher noise level than the highlight areas because of the push process (only visible in 100% view). Usually this shouldn't be a huge problem, but in extreme cases it is possible that stock photo agencies (etc) will turn down pictures because the noise level of the images might be too high although the picture seems to be ok in normal view.
The technologies above are common approaches of every professional landscape photographer, but with some practice the tips and tricks are also easily suitable for amateur photographers. It is very important to develop a feeling for the dynamic range of a scene. Advanced cameras offer tools like histogram or warning instruments for under- and overexposure. As a result incorrect exposures on high contrast images should eventually come to an end and landscape photographers will hopefully be able to enjoy their travel time without any further disappointments.
Article originally published on Spyderblog, Datacolor