The Art of Capturing Light
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 factors are essential in photography, and, with some creativity, photographers may create some very interesting photos by fiddling with them.
- Aperture -The size of the opening formed by the blades within the lens. The smaller the aperture, the less the amount of light is allowed through the lens. Aperture has a direct effect on the depth of field: the bigger the aperture, the shallower the depth of field is.
- Shutter Speed – The amount of time, usually in fractions of a second, that light is allowed to pass through the lens. If shutter speed is short, the subject being photographed will appear sharp and clear. Creative photographers may intentionally slow down the shutter speed to create Long Exposure photos; the featured image above is one such example.
- ISO – 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.
Take the featured image above for example. It was taken at a friend’s house a while ago. It was an indoor setting and because I did not have a flash unit with me, I increased the aperture size to f/1.4 to allow more light in so the dim environment could be compensated. I then set ISO to 400 to allow enough light in while maintaining a level of image quality at the same time. The shutter speed was set to 1/60 seconds, long enough to capture the light but not too long to have any noticeable blur on the main subject. All adjustments were done within limit so the image is correctly exposed.
This photo is of a different setting. It was shot during one of my trips to Taiwan and because I already decided to capture light trails, I set the shutter speed to 30 second so light trails could be formed with the headlights and taillights of the vehicles passing by. To compensate for the extended exposure time, I reduced the aperture size to f/22 so less light is allowed; it also gives a deeper depth of field so objects are sharper in the image. I also adjusted the ISO to 100 so the sensor is less sensitive to light and provides better image quality.
Now, when you see a beautiful photo and you want to know how it was taken, just think about the three factors and their respective effects and you will know the answer.