Why Megapixels Matter Less Than You Think

There is often a big price difference between a 20-megapixel camera and a 50-megapixel camera. Understanding the value of megapixels is essential to avoid wasting money. 

Coming to you from Nathan Cool Photo, this insightful video explores how you might be spending unnecessarily on high-megapixel cameras. Cool explains the concept of visual acuity—how sharp our vision is and how it relates to megapixels and sensor size. He starts with a simple calculation based on the common eye chart, using an angle known as arc minutes. This basic trigonometry helps understand how far we see something clearly and translates it into a constant, which is used in a simple formula to determine the necessary pixels per inch for printing or viewing images.

This video shows how distance impacts perceived sharpness. At one foot away, 300 pixels per inch (PPI) is needed for a sharp image. But as you move back to two feet, this drops to about 150 PPI, and at three feet, it’s around 100 PPI. This demonstrates that for most practical purposes, high megapixel counts don’t always translate to noticeable improvements in image quality, especially when viewed from a typical distance.

A comparison of cameras highlights that higher cost doesn't provide proportionate benefits for most use cases. For example, a 24-megapixel image printed at 300 DPI can look very sharp up to about 17 inches wide. However, when printed at 150 DPI, suitable for viewing from two feet away, the print can be around 34 inches wide. Therefore, for most prints and viewing distances, a 24-megapixel camera suffices, and the benefits of 45 megapixels are minimal unless you're printing very large images.

When considering large prints, megapixels do make a difference, but often not as much as you'd think. For instance, a 48-megapixel camera might offer better cropping ability for wildlife photography, where heavy cropping is sometimes necessary due to distance from the subject. However, for genres like real estate, portrait, or landscape photography, a 24-megapixel camera is often more than adequate.

Cool also points out the diminishing returns of high megapixel counts. More megapixels mean smaller photo sites on the sensor, which can lead to less light capture and more noise, particularly in low light. This is why video cameras don't need high megapixels—4K resolution, common in high-quality video, is only 8 megapixels. Thus, for video work, fewer megapixels can be advantageous.

Understanding these factors helps in making an informed decision about purchasing a camera. The need for higher megapixels depends largely on your specific use case, such as extensive cropping or large print sizes. For most, investing in lenses and other equipment might offer better value than chasing the highest megapixel count. Check out the video above for the full rundown from Cool.