Digital cameras have the advantage of being able to preview the pictures that you take immediately after so that should you be unhappy with the results, you can always retake the picture immediately.
You would however have also noticed that a lot of times, what you see on the LCD preview may not actually represent what the final picture looks like when you view it up close on a computer or when you print it out. A number of factors can contribute to this. The way your computer monitor and printer are set up can affect what you see drastically. A computer screen with the correct brightness and contrast settings will definitely display a more accurate picture.
How do you adjust the settings, or calibrate your screen to achieve this then? Unfortunately, this topic is in itself a specialty on its own but lots of guides exist on the Internet that can help you calibrate your monitor accurately. A very clear and simple site that I would recommend would be the pages at this site, which contains excellent tips for monitor calibration. Of course, there is always the option of purchasing specialized hardware to perform this task, which is what I chose to do for this site.
How about the LCD on your camera then? Unfortunately, there is no easy way to adjust the settings on this short of very basic controls like brightness. Also, lighting conditions can affect the way you perceive pictures on the LCD, especially if you are viewing the LCD in bright sunlight.
How then can you gauge whether if your picture is correctly exposed. If you have a histogram function/tool on your camera, use that. A levels histogram is basically a graph that illustrates the distribution of light/tones within your picture with dark tones represented on the left side of the graph, and bright ones on the right. A correctly exposed picture should have the graph falling between the two extreme ends of the graph. One that is underexposed will have a graph skewed to the left, and vice versa for overexposed shots. As long as the graph is distributed neatly from the centre, chances are the picture will appear all right on screen, and on print. To understand more about histograms, you may like to visit this very well-written article located on The Luminous Landscape.
Histograms demonstrating (from top: overexposure, underexposure, and a correctly balanced exposure). The histogram is a very powerful tool in the field for evaluating the exposure accuracy of your shots.
My personal experience is that it is always better to slightly underexpose a picture. The problem with overexposure is details are lost or burned out in the bright areas. Details somehow remain with the darker side of things! A slightly underexposed shot usually retains enough details that can be easily brought out with an image-editing program (and more so if you use the RAW file format!). As a result, I never fully trust the metering of my camera and prefer to underexpose on purpose, my shots by one-third to two-third of an exposure stop.
A shot with very tricky lighting: The bright sparkles from the water on the right had to be correctly exposed but at the same time, the child and the shadow needed too to have enough exposure time so as not to lose details. The compromise I did was to actually expose for the water (meaning that most of the rest of the shot ended up underexposed!). Details in the child were however preserved and later recovered in RAW / Photoshop processing.
Addendum: After the above article was published, I chanced across Michael Reichmann’s excellent article “Expose (to the) Right” in The Luminous Landscape. This gave new light on the intricacies of digital exposure as opposed by the traditional teachings of underexposing to preserve details on film. Do take a look at his excellent article on how to make sure that you “expose right”!
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