Appendix A: Essential Photography Concepts
This appendix offers a quick refresher course on a few of the most important concepts of photography. This section is meant for people relatively new to dSLR cameras. Although advanced users may be familiar with these concepts, there still may be some new information here for you as well. For example, having a grasp on concepts such as depth of field and composition are the building blocks of creating great images.
Exposure
By definition, exposure as it relates to digital photography is the total amount of light collected by the camera’s sensor during a single shutter cycle. A shutter cycle occurs when the Shutter Release button is pressed, the shutter opens, closes, and resets. One shutter cycle occurs for each image (with the exception of multiple exposures, of course). An exposure is made of three elements that are interrelated. Each depends on the others to create a proper exposure. If one of the elements changes, the others must increase or decrease proportionally or you will no longer have an equivalent exposure. The following are the elements you need to consider:
▶ Shutter speed. The shutter speed determines the length of time the sensor is exposed to light.
▶ ISO sensitivity. The ISO setting you choose influences your camera’s sensitivity to light.
▶ Aperture/f-stop. How much light reaches the sensor of your camera is controlled by the aperture, or f-stop. Each camera has an adjustable opening on the lens. As you change the ...
