Blog about Digital Cameras
[09/11/2010] Exposure and its implication in photography
In photography, exposure is the amount of light that falls in the film or on the image sensor when a picture is taken, and is determined by the camera’s shutter speed and aperture. In order for a photograph to be taken on a first place, the photographic material, the film in the “traditional” cameras and the image sensor in the digital cameras, has to be exposed to light. The whole process starts with the photographer pressing the shutter button after which the shutter opens and closes quickly and allows the photographic medium to be exposed to a certain amount of light, which amount can be controlled by increasing or decreasing the shutter speed. However, the light could be controlled via the aperture as well as narrower aperture “lets in” collimated rays and results in darker image, while wider aperture admits uncollimated rays. The aperture is denoted as F-stop and the smaller number indicates wider aperture (opening) of the lens.
Different exposure is achieved via a combination of various f-stop (aperture) and shutter speed settings and can have an enormous impact on the photos. The two extremes are the overexposed and underexposed images, where all the bright parts are practically white and all the dark parts are practically black respectively. Unless an artistic element is sough or the images are intentionally over or underexposed, these two extremes are not desirable. The vast majority of the today’s digital cameras come with Auto modes that automatically detect the shooting conditions, including the amount of the available light, and select the optimal combination between shutter speed and aperture, thus achieving the desired exposure. However, many models come with various manual settings that allow the photographer to achieve a “manual exposure” by choosing the aperture and shutter speed settings by hand. This is the preferred way of setting up the exposure as wider aperture results in increased exposure, but this is often achieved at the expense of decreased depth of filed.
Another element that should be taken into account is the sensitivity of the film or the image sensor – in the film cameras, choosing a medium with different sensitivity meant replacing the camera film with another, while the digital cameras allow the user to simply “dial in” the sensitivity of the image sensor. The light sensitivity in the film cameras is expressed as ISO and a film that requires more exposure to light has lower ISO, while the digital cameras use an ISO equivalent in order to let the photographer choose the appropriate settings. The appropriate exposure could be determined by taking into account the ISO of the media and then choosing the proper combination of shutter speed and aperture.
Other articles from this category:
[19/07/2010] Holding a Digital Camera
[19/07/2010] Manipulating Exposure in a Digital Camera
[19/07/2010] Significance of Shutter Speed for a Digital Photographer
[19/07/2010] The Art of Taking Great Group Photos
[24/07/2010] Children as a Part of Traveling Photography Collection
[24/07/2010] Understanding Aperture and Shutter Speed in an Entry-level Point and Shoot Digital Camera
[27/07/2010] The Art of Taking Great Group Photos
[27/07/2010] Photographic Composition – Planning, Improving and Story Telling
[28/07/2010] Capturing the Splendor of Fireworks Displays
[28/07/2010] Before Taking a Digital Photograph
[08/11/2010] What to Look for to Take Night Photography
[09/11/2010] Don't Get Caught Up in Megapixels
