|Digital Camera Basics... Some Vocabulary - Page 1 of 2
Shopping for a digital camera can be a difficult task considering the sheer number of choices out there. The number of manufacturers, models, and price ranges that need to be sorted out make the process difficult enough, but throw in all the buzz-words that need to be understood, and even a short list of cameras can become difficult to analyze.
This Tech Tip will take a look at a few key words that may come up when researching a digital camera, and will hopefully reduce the headaches associated with the process.
Digital images are composed of thousands or millions of tiny squares called picture elements, or pixels for short. Each square has its own color assigned to it, and the compilation of all of these little colored squares allows for images to appear smooth when viewed at original size. If an image is magnified several times, the appearance of the pixels can become more obvious, and at high magnifications each colored pixel can be distinguished individually.
Basically, the term megapixel means one million pixels, and it is used to describe the maximum number of pixels found in an image produced by a digital camera. It is generally the criteria used to classify cameras, and checking the Geeks.com selection shows that their cameras are all sorted into ranges of megapixels (MP).
Many people assume that because cameras are marketed so heavily by their megapixel specification, that this is the single most important criteria when choosing a camera. More megapixels do not necessarily equal better images, they mean larger images (both in physical size and in file size).
The megapixel count is achieved by multiplying the number of pixels in one horizontal line by the number of pixels in one vertical line. So, if a camera can produce images at a maximum resolution of 1600 by 1200 pixels, it is a 1.92 megapixel (1,920,000 pixel) camera.
It is not fair to assume that the images from the 5.0 MP Kodax CX7525 are automatically better than those from the 4.0 MP Kodak CX7430 strictly based on their megapixel count. All it means is that the maximum image size of the CX7525 is 2560 x 1920 and the maximum image size of the LS743 is 2408 x 1758. Many other features in the cameras can impact the quality of the images they produce, and may be far more important for the typical user to consider than the maximum overall size of each image.
Larger image size may do nothing for a user who only wants to view images on his computer screen, or for use on the web, but the higher megapixel images are important for those looking to make prints of their images. Generally, higher pixel counts in an image translate to the ability to create larger prints.
Sensors - CMOS and CCD
Digital cameras use a small sensor to capture the image before transferring it to flash memory for storage. Equivalent to a negative in a film camera, these sensors come in a variety of sizes, with most being between 20 and 40 millimeters squared. There are two types of sensors that may be found in cameras: CCD (Charged Couple Device) and CMOS (Complementary Metal Oxide Semiconductor). CMOS sensors are usually found in cheaper cameras and offer lower image quality than a CCD sensor that would probably be found in a more expensive camera.
There is an exception to the rule that CCD is better than CMOS, and that is with the Digital SLR-type (Single Lens Reflex) cameras. They use a much larger sensor (greater than 300 millimeters squared) and can provide excellent image quality, but the quality does come with a much higher price tag.
Zoom - Optical and Digital
Most digital cameras offer some sort of zoom, but it is important to identify which type is being provided. Optical zoom functions just as on a film camera, where the lens physically moves to produce the magnification. Digital zoom uses circuitry to enlarge a portion of the standard sized image and crops the content outside of the zoomed area. The quality of images produced using digital zoom suffer due to the nature of the process, and optical zoom is a far more desirable feature.
The price of a camera with optical zoom may be a good deal more than one with digital zoom, but the quality of the images cannot be compared. The Kodak CX7330 and the Kodak CX7300 are comparable cameras in many regards, but the CX7300 features only digital zoom, while the CX7330 features both optical and digital zoom for about $30 more.
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