MEGA PIXELS MEGAP ARE NOT IXELS
Image sensors have limitations. Two sensors of diferent sizes, a larger one in a DSLR and a smaller one in a smartphone, can have the same number of megapixels, i.e. the same number of pixels on their sensors, but the larger sensor in the DSLR will produce a better image.
That’s because the smaller sensor crams more photosites onto a smaller surface area, thus each photosite is smaller and its ability to capture light is lessened. It’s like two people who each have the same number of buckets to collect rain water, only one has larger buckets and the other has smaller ones.
Generally speaking, larger sensors with larger photosites produce better looking images. This is not always true, but all things being equal, a larger sensor can capture an image with more clarity, a higher dynamic range, more accurate color and with less image noise. So while it looks like you should just have more megapixels on bigger sensors, the reality is that it’s more of a ne balancing act than a simple combination.
But photosite size is just one part of the picture the number of pixels is another. ith fewer pixels you sacrice image detail - there are less pixels to ‘draw’ the same amount of information as a similarly-sized sensor with more pixels. Remember that a digital image is composed of individual dots, or pixels. The more there are, the ner your images can be. A rough example would be the between the -bit NES graphics of yesterday, and today’s fullHD PlayStation 3 games.
The sensors in mobile phones face a double challenge, they aren’t as big as the sensors found in digital cameras, so they
have to compensate with more megapixels to ‘draw’ more detail. But if they cram too many megapixels in a small sensor, they face the risk of degrading the nal image quality.
Further, while sensor size and pixel count are reliable indicators of image quality, they don’t form the entire picture. Improvements in image quality can be made from advances to sensor technology and image processing as well.
The more pixels you have, the finer the detail you can capture in an image.
Imagine that each red block represents 1 million pixels. Even though these two sensors have the same number of pixels, the pixels or photosites on the larger sensor are bigger. This is why, even though a DSLR camera and a smartphone can both shoot at 12MP, the images from the DSLR camera’s larger sensor will look better.