Understand Digital Photography exposure – The Exposure triangle

Photography is all about capturing light and turns it into pictures. To get a good picture one have to know how to control the right amount of light going into your camera. This is also known as photography exposure.

Now with digital camera, and powerful photo editing software, it is very easy to edit a wrongly exposed photo and correct what is wrong and make it right. In some circumstances, you may still archive some desire result.

However image post processing may help you archive some result, not all kind of images can be process to perfection, especially when the image is too far under or over exposed.

So it is very important that during photography, correct digital photography exposure technique is use to minimize badly expose photos. And in order to know this technique, it is important to understand the exposure triangle and how all 3 elements relate to each other.

Here are the 3 elements that form the Exposure Triangle.

1. ISO setting
2. Aperture
3. shutter speed.

ISO is simply referring to the sensitivity of the camera sensor relative to light. It has a number ranged from as low as 50 to as high as 3600. ISO of 50, 100 or 200 are consider as less light sensitive compare to ISO of 1600 or 3200.

Shutter Speed is how long in "time" does the sensor is exposed to light. The exposure time is control by a mechanical shutter that acts like a window. When the camera trigger is pressed, the shutter will open and the duration will be determine by the period of time and hence is known as shutter speed. Therefore the shorter the time, the higher will be the shutter speed.

Aperture will be the opening of the lens which allow light to pass through. It is also know as F stop. The aperture is responsible to creating certain amount of Depth of field in your picture. For high aperture setting, the lens opening is small and hence the depth of field is deep, give a longer focus range but the amount of light going through will be reduced. On the other end, when the aperture setting is small, the lens opening is big, allowing a lot of light to go into the camera but reducing the depth of field. You will now have a shorter focusing range.

In order to get correct digital photography exposure, this 3 elements must work together and compensating each other.

For example, when photographing bright environment, low ISO is used, the photographer will have to determine the correct shutter speed and aperture for the photo. What rules the values of the shutter speed and aperture will depends on the desire results of the photo. If the photographer wants to capture high motion object then he may choose to us high shutter speed and compensate with bigger Aperture operning as high shutter speed needs more light to go into the sensor.

Here is just a brief about how the exposure triangle is formed from these 3 elements.

If you wish to learn more in details on the characteristic of ISO, Shutter Speed and Aperture and how to use it to bring great results to your photo, I suggest that you read this book, Learn Digital Photography Now by Dan Feildman