It has been a long while since my last post. I have been busy these past few months with school, work, and other things life threw at me, and was unable to write as much as I would like to have. Now that my MBA study is coming to an end, I’m starting a series of photography tutorial posts to document what I know and hopefully to serve as a starting point for some would-be photographers.
The first thing you need to know about photography is the Exposure Triangle. The word “photograph” consists of two parts: photo-, meaning “light” in Greek, and -graph, meaning “to record”. In other words, a photograph is a recording of light, and photography is the art of capturing light. The amount of light captured is determined by three factors: aperture, shutter speed and ISO. These three are collectively referred as the Exposure Triangle, and, with some creativity, photographers may create some very interesting photos by fiddling with them.
Aperture is the opening formed by the blades within the lens. The smaller the aperture, the less the amount of light is allowed through the lens. The size of aperture has a direct effect on the depth of field: the wider the aperture, the shallower the depth of field is. Size of aperture is measured by ‘f-stop’, which is clearly marked on the lenses. When you move from one f-stop to the next, such as moving from f/1.4 to f/2, it doubles or halves the size of aperture as well as the amount of light allowed through the lens depending on the direction of the move. As the f-stop goes up, the size of the aperture decreases and the depth of field increases, and vice versa.
The aesthetic quality of out-of-focus blur created with shallow depth of field is called bokeh. It is quite common to see bokeh being applied on portrait photography, but it is also useful when photographing other objects. Although bokeh is usually used to help the main subjects stand out by blurring the background, some photographers may choose to blur the main subject to put emphasis on the foreground or background elements.
Shutter speed is the amount of time, usually measured in fractions of seconds, that the shutter remains open to allow light to pass through the lens. If shutter speed is fast, the subject being photographed will appear sharp and clear; if shutter speed is slow, there may be motion blurs on the edge of the subject. Photographers may intentionally slow down the shutter speed to shoot Long Exposure photos. Depending on the brands and models of the camera, shutter speed can be as fast as 1/16000 of a second, or as slow as several months or years.
When choosing a shutter speed, it is recommended that it be inversely proportional to the focal length of the lens unless you are shooting long exposure photos. For example, if you have a lens with a focal length of 35mm, then your shutter speed should be no slower than 1/35 second to avoid visible motion blur around the edge of the subjects. If a slower speed is needed, either set the camera on a tripod or a solid, stable object and use the shutter remotes to activate the shutter.
ISO is the measure of the film’s or sensor’s sensitivity to light. When shooting with low ISO, it may take significantly longer to capture enough light to achieve the desired result than it takes for high ISO. On the other hand, when shooting with high ISO the images tend to have a lot graininess, also known as noise, that may ruin a nicely composed photo. Typically, photographers would try to lower the ISO as much as the circumstance allows, and would employee accessories like flash or reflector to brighten up the scene.
In general, high ISO is used when facing a low light situation such as indoor scene with few light sources. Because of the amount of available light, it is necessary to either extend the exposure time (slow shutter speed) or to turn up the ISO value. Since extending exposure time requires the use of accessories such as tripod and shutter remote, photographers may want to consider using a higher ISO when such accessories are not available or the setting does not allow their uses. In the photo below, because the scene was dimly lit, higher ISO was used to bring out the details of these old machineries. As a result, some of the surface appears rather grainy because of the noises created by high ISO.
Please keep in mind that whenever your change one of these elements, you must also adjust at least one other element to compensate. If you own or have access to a DSLR, try to play with these three elements, get familiar with the effects they have, and experiment with different settings and environments. It may be daunting to learn to control these three elements, but you will find it worth the effort once you understand them and is able to use them creatively.