Digital Cameras - Best Picture Quality: 6 MP!

“The more pixels, the worse the image!”

But why? Well, compact cameras are supposed to be small and reasonably priced. Therefore small image sensors, e.g. format 7.5 x 9.4 mm or 5.4 x 6.8 mm, are built into the cameras. To increase the pixel count, the sensor has to be divided into smaller and smaller pixels.

The result is a decrease in sensitivity of the camera and an increase in noise because the amount of light collected by a single pixel is smaller. At the same time, increasing the number of pixels is supposed to lead to more details (resolution), but in order to achieve that better lenses with high resolution and a lower lateral chromatic abberation are needed. However better lenses are bigger and don’t fulfill the requirements for ’small’ cameras any more.

In the meantime, the pixels have become so small that the physical phenomenon of diffraction causes a loss of details with smaller apertures (with pixels below 2 microns already from f-stop 3.5). In addition, the data sizes of uncompressed images from cameras with 12 megapixels are approx. 36 MB/ picture. This data flood results in long editing times and requires huge storage capacities. So actually, what is critical for the listed problems isn’t the number of pixels but the size of each one. But in order to make pixels bigger, the sensor must be enlarged and along with that the camera with the lens gets bigger. That defeats the point of how big a ‘compact’ camera should be for consumers.

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