If you do have something tall in the shot, you might want to consider if the shadow might prove interesting, but if not, it’s usually better photography lighting technique to place the main light so that the shadow from that tall object doesn’t cause you any problems.
Photography lighting techniques - Shape
I usually decide on which side of the subject to place the main light, depending on the shape of the photograph’s most important subject. If I’m shooting a studio still-life of a box of tissues, for example, I would most likely place my main light so that the top of the box was the “hottest” side of the box with the front side of the box being the second hottest side. There are classic / excepted ways of lighting different shapes, but there are times when you want to stray from the normal ways of doing things and there are times to experiment. A true professional will already know when to light safely and when to take chances. You can learn more about classic shape lighting from various web pages out on the web.
Photography lighting techniques -Texture
After I figure out which light direction (from the left or from the right) will give my main subject the best shape, I will then fine tune the placement of the main light to give the maximum texture. That’s assuming that I’m going for the most texture possible, and that’s 99% of the time.
I try to get the most texture possible by placing the main light so that it “scrapes” down the most important side of the main subject of the photo. When I say “scrape”, I mean “scrape”. There is one place where the light will create the maximum texture possible. Just an inch this way, and the surface will under lit and an inch that way, the light won’t light the subject enough. This phenomenon is even hard to see with the naked eye. I find that I need to actually take a shot and look on the computer. And this is definitely a time when working will little or no fill light, will come in handy. Without fill light, the texture will be much more apparent to you and then after you’ve determined the placement of the main light, you can bring the fill light up to its necessary level.
Photography lighting techniques - Highlights
After you’ve placed the main light where you think it should be to give you the most possible texture, you’ll need to check and see if there are any nasty reflections that are too objectionable to live with. If there are, you’ll probably need to move the light so that the nasty highlight goes away. Hey, what can I say… Life’s a compromise.
Photography lighting techniques - Shadows
The same goes with objectionable shadows as goes with objectionable highlights. If there’s a really bad shadow that you can’t live with, then you’ll need to move the main light and rethink your lighting strategy. One thing that I didn’t mention here yet is that you may consider the option of wreaking the composition a little to solve either your highlight or shadow problems. This may not always be possible with every shot, but sometimes the option is available and also the easiest or best solution to your lighting problems.
In this article, I’ve been writing using the example of a studio still life photography lighting techniques, but the same lighting techniques hold true when lighting people, or anything else for that matter. When photographing people, critical light placement might be a little less important simply because people tend to move around a little more often, making exact light placement less effective. I have made some really nice people photos where an assistant of mine has hand-held a spotlight, moving the light to match the angle of the models have. If she looked left, he moved left to maintain the same lighting on the models face.