May 14, 2011
An electronic digital camera works a lot like film camera in that light comes in through the lens and it is captured to create a picture. The way the image is captured is what makes an electronic digital camera different than a film camera. With a film camera, you press the shutter button which opens the shutter letting in the light. The light entering the lens is exposed to the film and causes chemical reactions within the film to create your photograph. In a dslr camera the picture is captured with an image sensor that converts the light rays into electronic signals which are then kept in a file in the buffer memory.
The light detector or image sensor is known as charged couple device (CCD) and it is comprised of individual light sensitive picture elements typically referred to as pixels. Digital cameras are often measured in megapixels or millions of pixels. A camera which has a 3000 x 2000 array of pixels on the image sensor would contain 6,000,000 pixels and would be known as a 6 megapixel camera. As soon as the light hits the CCD it breaks it down to the millions of pixels and measures the amount of light and color to get a number for every pixel. Your digital picture is actually a long string of numbers that’s stored at a file in memory. The LCD screen on the back of the camera shows you the picture that the CCD is capturing.
Digital photographs have to be compressed or the file size is enormous and fill up way too much memory. The most typical compressed format is JPG which means Joint Photographic Experts Group. The higher the level of photo information is kept the greater the image quality and the bigger the file. The more compressed the photo is, the lower the quality and the smaller the file size. The smaller file size makes for shorter load times plus you are able to store more photos in memory. You do sacrifice quality however.
The fact that digital images are stored digitally means they easier to keep, share and manipulate. If you open up a picture inside an editor such as Photoshop, you are able to change the quality of the photo by simply clicking on a setting. Once you do that it changes the numbers that the pixels are storing to generate the effects. For instance, if you wish to make the picture 10% brighter, the image editor would alter the pixel numbers by 10 percent to show increased light or brightness.
Some digital camera models have built-in effects and you can make a photographic effect within the camera immediately after you take the picture. Something you simply can’t do with film cameras.