High megapixel images can bring out finer details.
Pixels are the smallest point of information in a digital image. Each pixel records color and intensity. A megapixel is one million pixels. Digital cameras have different sized sensors and different numbers of pixels per sensor. You can also choose different frame sizes when you take a picture. Each of these items affects the number of megapixels in an image. For printing or viewing, consider 300 dots per inch as the minimum acceptable final resolution.
Instructions
Sensor Pixels and Picture Dimensions
1. Digital images are made up of individual points called pixels.
Determine the sensor's pixel dimensions for your digital camera. This is stated in the number of pixels wide by the number of pixels high. For instance, a 6-megapixel camera might have a sensor that is 3000 pixels wide by 2000 pixels high. Multiplied together, this gives 6 million pixels of information.
2. Determine the frame dimensions for the picture. If you are taking photos in the 16:9 format, you can't use the entire 6-megapixel sensor. The camera will crop the digital image so the full width of the sensor is used, but the height will only be 1687 pixels, not 2000 pixels. The number of pixels in the resulting image will be 3000 x 1687 = 5,062,500 or about 5 megapixels.
3. Image sharpness depends on lens quality and stability as well as megapixels.
Determine the final dimensions for the photo. Common formats are 4 x 6, 5 x 7, 8 x 10. To maintain good resolution, plan on the final photo to have 300 dots per inch (DPI). Multiply the dimensions by 300 DPI to estimate the number of pixels needed for a good image.
4. Estimate your final image dimensions. For 4 x 6 inches, you need about 2 megapixels of information for a good image. At 300 DPI, that's 4 inches times 300, multiplied by 6 inches times 300 pixels = 1200 times 1800 = 2,160,000 pixels or about 2 megapixiels. For 5 x 7, about 3 megapixels is needed. For 8 x 10 images, you need between 7 and 8 megapixels.
5. When you use "digital zoom" or low-light features on your camera, the resulting image will have fewer pixels of information. Digital zoom works by cropping the image on the sensor to make it appear larger. The resulting image will have fewer pixels than the full sensor capability. When you use the low-light feature on your camera, the camera compensates by "binning" groups of pixels together for greater light sensitivity. The grouped pixels will only produce a single point of information in the final image, thus drastically lowering the number of pixels.
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