Why More Megapixels Is Sometimes Bad

For digital SLR owners, the megapixel war is over. Six megapixel is the magic number for most consumers who want “big prints” (ie. 8×10) and ten megapixel is the magic number for publication. Anything more is gravy.

Much more, and you could be running into alternate problems. When you cram more pixels onto a sensor of the same size, you’re making the pixels smaller, and smaller pixels have less capacity to handle light.

Think of sensors as a field of buckets. Light is rain, and when it rains, the buckets fill up with water. Bigger buckets can handle more water before they start spilling over than smaller ones. When water spills over, you get digital noise.

The new digital SLR war is in the realm of noise, and more accurately, the cameras ability to handle noise at higher ISO sensitivities. What good is a 20 or 30 megapixel camera if the pictures you take at ISO 1000 are noisy to the point of being unusable? That’s why a large format sensor is typically a better noise handler, and why cameras will more megapixels are generally not able to contain noise as well as their lower megapixel brethern.