I am often asked about megapixels.
They are not interesting, not anymore. Any camera over, say, 12 megapixels (Mp) will have enough resolving power to make nice big prints. Sure, if you shoot fashion you may want a 50 Megapixel camera, but for most of us, megapixels are no longer important.
They can even work against us – images get larger and take more disk space to store; transferring is slower; and so on. And there is another reason I say that megapixels no longer rule. A very important reason: electronic noise.
The more pixels you cram onto a sensor, and the smaller you make that sensor, the denser, and hence the smaller the pixels are. And small sensors create more such noise, leading to a lower signal to noise ratio. Basically, this means less quality at high ISO values. A small sensor camera with a lot of pixels crammed onto the sensor is not very good at high ISOs: it produces grainy images.
A modern top camera therefore often has fewer pixels. My Canon 1Dx has fewer Mp (18.1) than my previous camera, the older 1D MkIII which had 23 Mp. Hence, the new camera has truly great low noise performance at high ISO values.
Here’s a snap at 3200 ISO:
And I can go much higher.
So when you buy your next camera, do not ask about Megapixels: ask “how large is the sensor” (larger is better) and “how good is it at high ISO” (fewer Mp means better). Because when you can take pictures at night without having to worry about grainy images, you will be a happy camper.