A megapixel is one million pixels. It is a unit of image resolution. A camera with a 24-megapixel sensor captures 24 million pixels. A 50-megapixel camera captures 50 million. More megapixels mean more detail, which allows for larger prints and more aggressive cropping. But more megapixels are not always better. Smaller pixels collect less light, which can increase noise. More megapixels also mean larger files, which require more storage and faster computers to process.

The megapixel race has slowed in recent years. Most cameras now have enough resolution for most purposes. A 24-megapixel image can print at 300 pixels per inch up to 12 by 18 inches. That is larger than most people need. Higher resolution matters for landscape, architectural, and commercial photography, where large prints or heavy cropping are common. It matters less for social media, where images are compressed and displayed small. The quality of the pixels matters more than the quantity. A 12-megapixel image from a good sensor can look better than a 24-megapixel image from a poor one.

Megapixel facts

• Definition. One million pixels.
• Resolution. More megapixels mean more detail.
• Trade-off. More megapixels can mean more noise.
• Print size. 24MP prints up to 12x18 inches at 300 ppi.
• File size. More megapixels mean larger files.

Megapixels are a measure of quantity, not quality. A good lens, a good sensor, and good technique matter more than the number on the box.