Answer: Before Purchasing a Camera we need to look for the total effective pixels a digital camera poses rather than total number of Mega Pixels.
Reason: Sometimes we observe in an advertisement about Effective Pixels that are mentioned with total mega Pixels in a digital camera. We need to be very careful while checking the camera specifications as these pixel counts might be deceiving because Sometimes not even all sensor pixels are used. For example a 6 Megapixel camera might be having only 3 Megapixel effective Pixels and we need to be very careful as the output result will be only the 3 Mega pixels image.
Total number of Megapixels are the total number of pixels of a camera’s sensor. But for many technical reasons, not every pixel on the sensor is available for use in building an image.
“Effective pixels”, are also known as the “recorded pixels”. They gives the true count of the number of pixels that are really (In Real) used for capturing an image.