All digital cameras have a lens, an image sensor, memory cards, and record the images or video to transfer to your computer or printer. The difference in the price of the digital cameras comes when the quality of the parts is enhanced. The basic quality, which is given by any point-and-shoot digital camera to the high quality given by digital SLR camera, is mainly dependent on the quality of the lens and the megapixels of the image sensor. The more the number of megapixels, the better is the image quality of your digital camera photo provided other factors like superior internal processing software, superior lens, correct exposure and focus are taken care of.

Understanding megapixels
MEGA is one million. The word PIXEL was created by the combination of two words, namely, picture or PIX and ELement. A pixel is a small dot on the computer screen or on the television. Each pixel is composed of one color - red, green, or blue. The pixels are very small and so they appear to blend and form all shades of color including white. The human eye is twice sensitive to the color green, so the number of green pixels is twice than those of red or blue. They are arranged in a particular manner, known as the Bayer pattern. Other patterns like Foveon also exist in some cameras. Megapixel is one million pixels. For example, a 6 MP digital camera would have six million pixels to record the image. Hence, the more the number of megapixels, the more color information is obtained, resulting in more sharper and detailed digital camera photos.

Understanding the sensor
These pixels reside in a sensor, which is an electronic device. The sensor is made up of photosites, which are sensitive to the intensity of light. When a digital camera takes a photo, the light enters the camera and is focused on the sensor where the photosites evaluate the intensity of light and each pixel records the light as either red or green or blue as each pixel is covered by the Bayer pattern. Depending upon the quality of the sensor in the digital camera, it can record over 2000 shades of each red, green or blue color. Hence, the more shades of RGB (red, green, blue) are captured by the sensor, the more accurate is the color information, resulting in more original-looking images. The processor in the camera combines all the colors to produce the image as accurately as possible. Thin walls encase each pixel to prevent spillage of the light to adjoining pixels. The smaller the sensor, the smaller are the pixels, resulting in thinner walls between them, which may cause spillage of light to adjoining pixels, thereby diminishing the sharpness of the image. So, to get sharp pictures, a larger sensor is required. Besides the number of megapixels, and the size of the sensor, another important part is the software used by the camera to process all this information. The software has to be superiorly engineered to give good results. Correct exposure and focusing are also major points in a good quality digital camera photo.

The required number of megapixels
This depends on what will you do with the digital camera photos. If you intend to send it by email, or post on the web, or print in small sizes, you need a digital camera with 2MP or more. If you want to have sharper images, then you need a digital camera with 5MP or more. For professional work or to print in large sizes, you need a DSLR of 8MP or more. Remember, that just the number of megapixels in your digital camera alone does not guarantee a great digital camera photo, but yes, it certainly guarantees a good digital camera photo.