The nutshell explanation of how a digital camera works is that light lands on a sensor, which converts the light into electrical signals.
Depending on the kind of camera you’re using, how the light reaches the sensor may seem different but the sensor fundamentals stay the same.
The sensor is where most of the megapixel stuff comes from. When you press the shutter button, the sensor (like film in old-school cameras) is exposed to light for however long you have the exposure time set for, which for many ordinary camera users is automatically preset.
Generally, the more pixels packed onto a sensor, the higher the resolution of the images it can produce. A megapixel is 1 million pixels, so a 12-megapixel photo has a resolution of about 12 million pixels. The most recent crop of point-and-shoot digital cameras from manufacturers like Canon, Nikon, Sony etc seem to establish 10-12 megapixels as the new norm for everyday pocket cameras, and some crazy phone manufacturers like Sony Ericsson crammed a 12-megapixel into their Satio mobile phone, the same as Canon’s entry-level XSi DSLR and Nikon’s D700 pro DSLR. DSLR stands for Digital Single-Lens Reflex, which for the purpose of this article should simply mean a professional camera, like the ones those professional photographers use.
Obviously, there’s a world of difference between the image quality you’re going to get out each of those. Most of it comes down to the size of the sensor and the pixels. You can fit a much bigger sensor inside of a DSLR than you can inside of a mobile phone, which not only means you can fit more pixels on the sensor, but also fit much bigger ones. Sure enough, the sensors inside of DSLRs are huge compared to the ones in mobile phones. To get really high-resolution smaller cameras and phones, manufacturers pack as many teeny pixels as tightly as they can onto tiny sensors.
The pixels in standard point-and-shoots are not the same kind of high-quality pixels found on DSLRs. So, on a given sensor size, a lower megapixel count with bigger pixels will produce cleaner images hence the professional Canon or Nikon having only 12 megapixels with way better pictures than your 12 megapixel camera phone.
When it comes down to buying cameras for regular people, just keep in mind that more megapixels isn’t necessarily more better. It’s how good those pixels are that matters.
Source: Daily Monitor News