Light in the Darkness
The difference between good and outstanding images
Deutsche Version im “Fotomagazin” November 2011
Light is the cornerstone of all photography, and the search for perfect light is a large part of every photographer's lifelong search for the perfect image. Although the perfect image probably doesn't exist, we all still want to get as near as possible to the myth. A big step in the right direction involves finding unusual situations in which a subject appears especially radiant or particularly well highlighted. When we are photographing nature or wildlife, this "special" type of light occurs in the early morning, shortly before and after sunrise, and in the evening around sunset. Dramatic changes in weather are often accompanied by unusual light, and a brewing storm always produces a unique visual mood. In contrast, perfect "vacation weather" with bright sunshine and blue sky is not always a wildlife photographer's best friend. When the sun is high in the sky, you will often end up with fl at-looking images and hard shadows. A successful landscape photographer has to adapt to the rhythms of natural lighting cycles and, to be sure of getting exceptional results, a wildlife photographer has to adapt to the habits of the subject too. It is actually a healthy way to live, getting up early and marching off into nature with the prospect of a restful lunchtime nap and an afternoon session to round out your day. If you are lucky, you will fi nd a cozy bar on the way home to give you time to collect your thoughts before giving your attention to your family or your day's haul of photos. But simply changing your pace of life doesn't ensure great photographic results. You have to learn to recognize unique lighting situations when they occur or, better still, to predict them while they are still forming, thus giving you the best possible opportunity to grab your shot during the few seconds or minutes when everything comes together. An additional challenge lies in the fact that our cameras are not generally programmed to deal with exactly the type of unusual lighting we are looking for. Exposure meters and automatic exposure modes are designed to cram our wonderful subjects into the available dynamic range using any means possible, and when this doesn't work they tend to strongly under or overexpose. Automatic white balance systems often deliver very good results in high-contrast situations, but can only reproduce 18-percent Kodak gray when shooting in early morning mist. I recommend using a manual white balance setting of 7000K or more for images of sunrises and sunsets otherwise, most RGB-based cameras will include a non existent green tinge in the mix that is diffi cult to correct later.
Many photographers simply shoot in a RAW format and assume that they can correct any anomalies later. But take care-this approach is only really practicable if the image data you capture lies well within your camera's dynamic range. Otherwise, highlights and shadow detail will be irretrievably lost. We have to learn to perform any necessary corrections while we are shooting and decide on the fly which details we can possibly do without in the final image. Generalized correction measures-such as preserving highlights in backlit subjects don't really help, as underexposure always reduces overall resolution and increases image noise.
Example #1: Early morning light at sunrise
These three photos of a lion were taken within a space of just a few minutes, but show three completely diff erent eff ects.
with the fi rst rays of light shining directly on the lion’s face Canon EOS-1 Ds Mark III, EF 800mm f/5.6L IS USM , 1/750s at f5.6, Neutral, ISO 400, WB: Auto, Tv, Exposure compensation +1, (working within the RAW headroom, the highlights on the lion’s mouth are retrievable) Reason for these settings: To avoid noise in the shadows on the animal’s body
with the lion’s head as a silhouette Canon EOS-1 Ds Mark III, EF 800mm f/5.6L IS USM, 1/500s at f5.6, Neutral, ISO 200, WB: Auto, Tv, Exposure Compensation -4, Reasons for these settings: to capture only the highlights, but such strong compensation creates unwanted clumps of color during RAW conversion, shadow areas with little or no detail defi nition (i.e., that contain virtually no image data) have to be selectively denoised
overview snapshot in hazy backlight Nikon D3, AF-S Nikkor 200-400mm f/4G ED VR set to 300mm, 1/1000s at f4, Neutral, ISO 2200, WB: Auto, Tv, Exposure compensation -1, Reasons for these settings: To preserve highlights. Perfectly sharp images are impossible in strong backlight, making it easier to accept the loss of resolution caused by negative exposure compensation
Example #2, Early morning light at sunrise
sunrise overview with migrating gnus Nikon D3, Nikon D3, AF-S Nikkor 200-400mm f/4G ED VR set to 380mm, 1/800s at f11, Neutral, ISO 200, WB: Manual 7500, Tv, Exposure compensation -1.67 Reasons for these settings: Manual white balance setting suppresses a green cast in the sun’s aura; exposure settings preserve the overall eff ect of the sun. Once again, the lack of sharpness in backlit images makes a negative compensation value acceptable. The virtually detail-free foreground has to be selectively denoised later.
sunrise with gnus in backlight Canon EOS-1 Ds Mark III, EF 800mm f/5.6L IS USM, 1/250s at f11, Neutral, ISO 400,WB: Auto, Tv, Exposure compensation -1, Reasons for these settings: Exposure settings minimize strong tonal jarring with hard color transitions. As above, backlight makes the eff ects of negative compensation values acceptable.
If you are not an experienced photographer and you have just read the technical data listed for the photos reproduced above, you might just be considering putting your camera away and giving up. Please don't! The basic rules of photography and image composition are simple to learn and digital cameras have a lot tricks up their sleeves to help you get great results. Of course, your natural talent will determine whether you produce great or outstanding photos. But the real learning process begins when you ask yourself what you can do to improve a photo before you press the shutter button.
For example: if you are on safari, using a medium telephoto lens to shoot through your vehicle's window will give your photos a much more natural look than those shot looking out of the roof- although the diff erence won't be quite as obvious once you start shooting at subject distances of 25 yards and more using a 600mm or 800mm lens. One of a photographer's most important aids is a histogram that represents reality as closely as possible. You don't have to understand every last detail of a histogram as long as you learn to read and interpret what it is telling you about the behavior of the shadows and highlights in your image. Current camera technology can only display JPEG images that are processed in-camera and, if you have selected your camera's "vivid" color setting, you won't be able to accurately judge the necessary exposure settings. In backlit situations, the camera histogram can quickly end up showing 2EV (i.e, two whole f-stops) of overexposure with burned out highlights and too much overall brightness. If you set your camera to warn you about potential overexposure, your monitor can quickly end up looking like a fi rework display and is likely to tempt you to set -2EV exposure compensation. This would then reduce the resolution of the resulting images, giving you washed out shadows and increased noise. Always set your camera to its neutral (linear) color setting. The monitor will then display a much paler, lower contrast image, but it will at least be an image that represents the reality in front of your lens. In such situations, you can even risk overexposing your highlights by up to 1EV, as RAW headroom gives you the potential to recover any lost detail later. You can then use the "vivid" setting in your RAW converter to return your colors to their former glory while restoring any highlights and shadows detail that weren't completely lost during shooting. The other great advantage of digital cameras is their ability to display results immediately on the camera monitor. If you really don't want to get involved in interpreting histograms, you can always use your camera's bracketing function to take a series of images with exposure compensation values ranging from zero to -3 or -4. This way, you can be fairly sure of capturing at least one correctly exposed image while increasing your chances of shooting something exceptional. For working photographers who need to consistently produce the greatest possible resolution for print reproduction, the camera histogram is a kind of high-tech photographic bible. It is easier to shoot eff ectively using an accurate histogram than it is using just a monitor image to judge your results. Striking the right balance between 1/3 of a stop more or less aperture, shutter speed or ISO can make all the diff erence in the quality of the prints you can make from digital image files.
The Camera settings I use, in TV, AV, or manual mode:
* To help judge the histogram accurately
** To help find the right balance between aperture, shutter speed and ISO values
*** See previous text
In depth knowledge of the strange mountain range in your camera's display, called camera-histogram, isn't strictly necessary to produce great photos, but you do need to know enough to prevent any image details from becoming irretrievably lost. Only then can you select the appropriate exposure compensation values manually or using your camera's +/- button. The most important elements of a photo's composition, and at the same time the easiest to spoil by using incorrect exposure values, are the brightest areas (i.e., the highlights) and the darkest areas (i.e. the shadows). Overexposure of more than 1EV can ruin some highlight details, while underexposure in shadow areas produces additional image noise. Attempts to restore burned out highlights using a RAW converter quickly lead to gray, smudgy details, while artifi cially brightening shadows only increases noise. Very strong shadow brightening also produces so called "banding" eff ects, which are the subject of much discussion in a number of online forums. Digital cameras are generally not very good at reproducing shadow detail, and underexposure often shifts brighter tonal values toward this "blind" zone too. In turn, this also reduces resolution, increases noise, and raises the risk of producing banding effects.
The eye icons in the histograms reproduced below represent a digital camera's distribution of resolution in simplifi ed form. The aim of the illustrations is to show that shifting the central peak of the histogram too far to the left or right not only darkens or brightens the image. A shift to the right (i.e., making the image as bright as possible without burning out any highlights) increases overall resolution, while a radical shift to the left massively reduces resolution and signifi cantly increases noise.
To help you interpret the histograms, I have divided the image shown on the left into three colored zones. The darker tones that tend toward black are colored red, the midtones remain uncolored, and the highlights (including white) are colored yellow. Midtones are less signifi cant here, as they can nearly always be corrected later if necessary. However, if the histogram curve intersects with the red zone, the image will be underexposed, while intersection with the yellow zone indicates overexposure. If both ends of the curve are clipped, the camera's dynamic range is simply not suffi cient to capture the intended scene, and you will have to decide whether your image can better do without highlight details, such as dewdrops and refl ections (achieved by setting a positive compensation value), or shadow details (using a negative compensation value).
The histogram flattens out toward both ends of the scale and shows clipping neither in the highlights nor the shadows. Such a curve indicates that you are using the camera’s entire dynamic range (i.e. all reproducible tonal values) and you will be able to freely correct color and contrast without risking a loss of image quality.
Overexposure of more than 2EV:
Strong clipping on the right indicates that large portions of the yellow colored details will be irretrievably lost. The available dynamic and tonal value range are reduced to about two-thirds of their actual size. The highlights will remain burned out, even after subsequent correction.
Underexposure of more than 2EV:
Strong clipping on the left indicates that large portions of the red colored details will end up completely black and detailfree. The available dynamic and tonal value range have shrunk to half their potential size. Subsequent correction will leave the image with just half of the camera’s available resolution and create strong visible noise.
Exposure to the right
This picture* is even typical for our "most loved" weather in the northern hemisphere.
*Laptop screen shots with less resolution and colours
Typical camera automatic exposure for such kind of lightning situations.
The hole colour information tends to the left with lesser resolution. The right side shows about 1.5 LV without any kind of colour information, it's simply grey.
An exposure with + 1.5 Exposure Correction pushes the colour information to right with more resolution and less noise. Later corrections in raw converter or Photoshop are necessary (see page 12).
"Exposure to the right" is the most important rule in digital times.
The loss of resolution in the darker zones is much more higher than in film times.
To be able to judge a histogram according to even these three simple criteria, we have to set up the camera to provide us with a histogram that closely represents reality. As already mentioned, today’s cameras can only display JPEG histograms produced in-camera and, because we are all used to the strong colors reproduced in analog slides, we are easily tempted to use a camera setup that produces similarly strong colors on the monitor. In fact, it is just as easy reproduce vibrant colors using a RAW converter later on. If we use the right (i.e., realistic) setup and avoid using incorrect compensation values while shooting, most of the images we produce can be fully corrected on a computer.
Although newer cameras have many more color settings options, for the purposes of this article we will stick to describing the three most common:
The camera doesn’t artifi cially enhance contrast and saturation, resulting in images that appear pale and somewhat flat.
Standard: The camera enhances contrast and saturation slightly, giving the monitor image color and contrast levels that are similar to normal human vision.
Vivid: The camera adds a high level of artifi cial contrast and saturation to produce an eff ect similar to that found in low-sensitivity slide fi lms, such as the famous Fujichrome Velvia 50. The influence these settings have on the histogram display are shown below.
All three images were shot using the same exposure settings at early morning light just after sunrise (Capture NX simulation).
This version appears a little pale and, with the exception of about 1EV RAW headroom in the highlights, the JPEGbased histogram covers the full dynamic range of tonal values. Neither highlights nor shadows are clipped and no additional corrections are required at this stage.
This version is rather more attractive, but
the histogram is already displaying a slight dynamic range overshoot. Using the same exposure settings as in the previous example, the highlights appear to be clipped by about ½EV. No corrections are really necessary here, and the highlight clipping is still covered by our RAW headroom. Nevertheless, this camera setup could tempt you to use a -2/3EV compensation value, which would cause a slight loss of resolution and shadow detail.
This version displays vibrant colors and high contrast, but the histogram is telling us that we have far exceeded the camera’s dynamic range. Here, the highlights appear to be clipped by about 1½EV and the shadows by about 2/3EV. Again, no corrections are actually necessary, although the vivid setting is telling us that we need to set a negative compensation value of up to -2EV in order to preserve highlight detail. Such a correction would result in strongly reduced resolution and shadow detail.
The "neutral" setting produces the histogram that most accurately reflects the camera's actual capabilities. The "standard" version is acceptable too but can still be deceptive, especially in high-contrast or strongly backlit situations. The "vivid" setting is the best example of how to ruin your own eff orts by making unnecessary corrections while shooting.
By now, you might be thinking that it is easier to do without a blockbuster photo or two than it is to put your images through complex editing processes. However, it's easier than you may think to adjust your photos on a computer so that they look as vibrant as our false monitor image. Using the "curves" function in a RAW converter or Photoshop, you only have to perform one simple step to produce a slight S-curve (equivalent to the "standard" setting) or a more pronounced S-curve to reproduce the vivid setting. Adjusting an image this way clips neither highlights nor shadows and preserves your camera's full dynamic range into the bargain.
Now a second example with strong contrast's. Taking pictures in unusual lighting situations is more complicated and every time a compromise between acceptable sharpness/resolution and an acceptable dynamic range without a loss of important colour and detail informations. Before you press the shutter button, you have to calculate the physical capabilities of your camera and the later possibilities in post production, to find an more or less optimal exposure compromise. For this an example in the warm early morning light. It's one image from a series of three hunting cheetah's in back- or sidelight, wet grass and wet bushes with a lot refl exes, strong contrast's and high saturated colours. Except some burned out highlights in the waterdrops, the camera dynamic range was wide enough to capture the important colour and detail informations to show the real situation as near as possible.
Possible in-camera conversation
Vivit setup, - 2/3 exposure compensation. The blacks are slightly cutted, but the highlights in the fur of the cheetah are totally burned out. A highlight recovery (except a muddy gray without details) is impossible. On a first look, this picture seems to be okay, but for bigger size printing, the big white holes from the burned out highlights are not acceptable.
Raw-Data with the possible camera dynamic range
Neutral setup, contrast compensation to the lowest level, no exposure compensation. Highlights and shadows are not cutted, but the image looks very dull. Expect the highlights, this picture is underexposed. But for this kind of pictures in strong back- or sidelight with lesser physical sharpness and resolution, a slightly additional loss of resolution for exposure compensation is acceptable. Underexposure means every time a lot of grey without any kind of colour information or detail in an image. So we have to "kill" the grey in this image by raw-conversation or in Photoshop.
Raw-conversation and/or Photoshop masking technique
To kill the grey in this picture, in raw conversation we have to level the colour information a lot more to the right side of the histogram. Is this impossible without burned out highlights in your raw-converter, you can do that in Photoshop's layer and masking technique. For this picture a soft highlight mask in a second layer was enough to kill the grey in the ground layer.
Example #3, typical situations that only allow you to reveal the true mood of the situation by making corrections. Some of these can be made later, but are then likely to cause a reduction in overall
Dull, rainy weather
Nikon D2x, AF-S Nikkor 200-400mm f/4G ED VR set to 400mm,1/250s at f4.8, Neutral, ISO 100, WB: Auto, Tv, Exposure compensation +1.67 Reasons for these settings: Exposed “to the right” until the highlights end of the curve almost touches the right-hand end of the histogram. This increases resolution and a bit contrast without increasing shadow noise. Hue, tonality and saturation re-corrected in Photoshop.
Really murky, rainy weather
Canon EOS-1Ds Mark III, EF 800mm f/5.6L IS USM, 1/1000s at f5.6, Neutral, ISO 200, WB: Auto, Tv, Exposure compensation -1.0 Reasons for these settings: Slight underexposure is necessary to refl ect the real mood of the situation. This way, the almost white highlights don’t simulate excessive contrast. Hue, tonality and saturation re-corrected in Photoshop.
Early morning light with a thunderstorm brewing
Nikon D3, AF-S Nikkor 200-400mm f/4G ED VR set to 400mm, 1/40s at f4.0, Neutral, ISO 640, WB: Auto, Tv, Exposure compensation +1.67 Reasons for these settings: The scene exceeds the camera’s dynamic range. Here, we deliberately clipped the highlights by about 1.5EV, which caused a slight loss of tonal value in the zebra’s skin, but prevented shadow clipping and noise. Hue, tonality and saturation recorrected in Photoshop.
Early morning mist
Nikon D3, AF-S Nikkor 200-400mm f/4G ED VR set to 270mm 1/250s at f4.0, Neutral, ISO 220, WB: Manaul (7500K), Tv, Reasons for these settings: White balance increased manually by about 1200K. Mist is often portrayed in excessively cold light, but in this case, the sun was already shining from behind, giving the scene a warm overall look.
Canon EOS 7D, EF 24-70mm f/2.8L USM at 64mm, 1/500s at f4.5, Neutral, ISO 200, WB: Auto, Tv, Exposure compensation +0.5 Reasons for these settings: It would have been impossible to reveal any detail in the tree without using it as its own sunshade. There is no camera in existence that can handle a range of contrast this large. Hue, tonality and saturation re-corrected in Photoshop.
The evening “golden hour”—soft backlight with some accentuated highlights
Canon Eos 1Ds Mark III, EF IS 5,6 800 mm, 1/500s at f6.7, Neutral, ISO 200, WB: Auto, Tv, Exposure compensation +1.0 Reasons for these settings: In situations like this, you will simply have to accept a few burned out highlights in order to preserve color and detail contrast. Hue, tonality and saturation re-corrected in Photoshop.
Never stop learning
Photography is a lifelong "learning by doing" process, although those super multi-function wonders of modern technology called digital cameras are busy making photographers increasingly lazy. In analog times, the cost of fi lm alone made it necessary for photographers to plan their camera settings in advance and to check them carefully during the shoot using a light meter or mathematical formulae. In these digital times, even we professionals tend to simply "shoot from the hip". Technically speaking, this often results in a hit-rate of up to 90 percent, even in tricky lighting conditions. However, the very best photos are often amongst the remaining 10 percent.
If you are just starting out, you can certainly rely on your camera's programmed auto mode or custom shooting modes, switching to semi-automatic Av or Tv modes later to infl uence your exposure settings manually. Using bracketing sequences in very high-contrast situations ensures that you capture at least one good shot and will often reward you with unexpectedly good results. In today's digital age, pro photographers constantly have to reactivate their grass-roots knowledge and oldschool photographic instincts in the hope of maybe one day capturing that exclusive "perfect" image.
© Uwe Skrzypczak, November 2011
Translation by Jeremy Cloot
Only for personal use, public sharing reproduction or public printing without a permission is prohibited!
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Thank you for the very informative post. I really appreciated all the details about your shots, and especially showing the effects of shooting in vivid mode and how that can exaggerate clipping of highlights and shadows. I haven't been using the histogram yet when taking photos, but can see now how it can be extremely useful. I will try some of your ideas, I think they will help me as an amateur photographer aspiring to become better. Thank you also for the download of your book through dpreview.com. I'm looking forward to reading it and learning more. Best regards,
A very interesting and helpful description. Thanks for publishing your thoughts. Since my images are usually landscapes and macros, I have (usually) have enough time to adjust expose. In future outings, I'll put your advice to the test.
And thanks a million for your free offer to download your wonderful ebook, "Wildlife Photography"!