Digital Camera Basics
Shopping for a digital camera can be a difficult task considering the sheer number of choices out there.
- Pixels
Digital images are composed of thousands or millions of tiny squares called picture elements, or pixels for short. 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.
- Megapixels
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 (http://www.geeks.com/products.asp?cat=CAM) 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).
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
CCD Sensor at Digital camera
Digital cameras use a small sensor to capture the image before transferring it to flash memory for storage. 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.
CMOS Sensor Circuit
For more details about CMOS, please visits this website
- Zoom - Optical and Digital
Most digital cameras offer some sort of zoom, but it is important to identify which type is being provided. 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.
- Memory - Digital Film
- Aliasing
- Aspect Ratio
Aspect ratio describes the shape of a digital image, or any image for that matter, where the first number represents the width of the image and the second number represents the height. Standard film cameras generally use an aspect ratio of 3:2, but most digital cameras have adopted a 4:3 aspect ratio so that images better fit on a standard computer monitor.
- Connectivity
In general, cameras provide a cable to connect to a computer either via serial, USB, USB 2.0, or Firewire.
Some specialized cameras may take advantage of the high speed Firewire protocol for connecting to a computer. Some cameras don't require any cables at all, as they can transmit the images to a PC wirelessly.
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