Digital Camera Basics – Want To Stop Being An Idiot And Learn How Digital Cameras Work?

25th November, 2008
digital cameras
Mike Singh asked:

With the advancement of the digital camera and the software that is made for them, most pictures look professional from the first click of the camera. But like most things, it is important to understand the “how and why” for higher quality results.

The basics of a digital camera revolve around terms like pixel, pixel count, white balance, sensor, sensitivity, optical zoom, or digital zoom. These improve your understanding of what digital photography is all about, and will help you become a more efficient photographer.

For example, one important term is digital sensor. A typical digital camera may have a digital sensor element that is as big as a small finger nail. Most 5MP digital cameras use a sensor that is 7mm x 5mm in size. This is much smaller than the size of the negative of a 35 mm camera. However, high-end digital cameras have large sensors, and generate superior images. These are important things to know, to see how pictures can be better or worse.

Digital cameras also have sensitivity settings similar to ISO ratings on film. Most digital cameras will have settings for sensitivity equivalent to ISO 100 and ISO 200. Many also have a setting for ISO 400. A few expensive digital SLR cameras with large sensors have settings for ISO 3200 or even for ISO 6400.

Most digital cameras have an optical and a digital zoom. An optical zoom lens works by changing the focal length and magnification while the zoom is being utilized – with the image quality remaining high. Digital zoom works by cropping the image to a smaller size. The cropped image is enlarged to fill the frame, causing a significant loss of quality.

The manufacturers of digital cameras use the term “pixel count” to describe their camera’s image properties. The word pixel originates from “(PIC)ture (EL)ement”- with the use of phonics added for emphasis. It represents a single point in a graphic image – not a dot but an abstract sample that can be reproduced in any size, without a dot or square appearance.

A pixel is important to understand because it is the basic unit of measurement, used to define a digital photograph. The more the number of pixels per square inch, the higher the resolution of a digital picture, increasing its clarity. Some examples would be 2,400 pixels per inch, 640 pixels per line, or spaced 10 pixels apart. Designers, artists, and photographers sometimes interchange the pixel terminology, such as dots per inch (dpi) with pixels per inch (ppi). The dpi is used when it refers to the printer’s resolution for the printing density. Each pixel is made up of three color channels – red, green and blue-and has a numerical value of between 0 and 255.

The pixel count also decides the size of a print in case you want to print photographs. A 3MP camera can provide excellent 4×6 inch prints, while a 4 or 5MP digital camera can deliver high quality 8×10 inch prints. With a digital camera you can pick the white balance to suit the light source. This is meant to ensure that white looks white, and not yellow or blue. Normally, your digital camera will do this automatically. You can also set the white balance yourself for better effects.

Since each pixel generates three bytes of data, a photographer using a 3MP camera will need a storage space of 9 million bytes or 9MB to store a single image. This is a huge amount of space. Camera companies therefore allow for a compression of image using a format called JPEG. This reduces the file size significantly but while doing so a lot of data is lost. To overcome this problem companies have come up with different storage formats. Canon calls it RAW while Nikon calls it NEF. The data loss is less in these formats.

The low end cameras used by beginners can shoot images whose pixel count is one million is categorized as 1 MP or one million pixel camera because the intensity of each pixel is variable, with each pixel having three or four dimensions of variability – such as red, green and blue, cyan, magenta, yellow, and black. The high-end cameras used by professionals, can range from 14MP to 22MP with a pixel count as high as 14 million or 22 million per image.

The thing to remember is the higher the resolution, the more realistic the image is, matching closest what the actual image is. So take your time, do some research, and talk to people who know cameras. Otherwise, a lot of money will be spent on something that is barely adequate for what you want.

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