Are More Megapixels Better?

Here it is folks, the million dollar question: are more megapixels better?

More megapixels means more information in each picture you take which means the images are just plain better, right?

If you compare a 6 megapixel photo to one with 12, you'd easily be able to tell the difference in quality...at least it seems like you should.

But here's the fact of the matter: cameras with more megapixels don't necessarily capture higher quality images.

Instead, a higher megapixel count can be used to make larger prints.

In the Beginning...

The foundation of the megapixel is a solitary entity: the pixel.

A pixel is one tiny dot of color that makes up a digital photo. When you take millions of individual color points and place them in a rectangular grid, they create a digital image.

Obviously, it takes a lot of individual dots to create a photo: in fact, millions.

This is what the mega part in megapixel refers to. A 10 megapixel camera captures photos with 10 million individual pixels.

These pixels are contained within a rectangle that represents the width and height of your photo.

For example, when you take a photo with your digital camera, you might find that the exact dimensions of the image are 3,888 by 2,592 pixels. Multiply these two numbers together and you get the total number of pixels in the image: 10,077,696.

That's the math. The logical assumption that follows from this is that more megapixels = more individual pixels = higher quality image.

But this is only partly true.

It's All About the Medium

Imagine that you're looking at a 6 megapixel and a 12 megapixel photo of the same subject on your computer monitor.

If you are viewing the 6 megapixel image at full size (100%), you will have to view the 12 megapixels image at half size (50%) for the two images to appear the same size.

Looking at these two photos side-by-side on a monitor, you will have a tough time seeing any pronounced quality difference between them. If you view the 12 megapixel image at 100% it will be larger on your monitor, but not necessarily of higher quality than the 6 megapixel alternative.

However, if you now make prints of both images at a large size - say 20 x 30 inches - you WILL see that the 6 megapixel image produces a lesser quality print.

The above only applies when you make large-scale prints.

If you want to make prints at size 8x10, 5x7 and 4x6 then you will again have a hard time telling the difference between a 6 and 12 megapixel photo.

Put another way:

Large prints require more megapixels to preserve image quality.

This is because most high-quality printers will require between 200 and 300 pixels to print an inch of your digital photo.

If we take the 10 megapixel example from above and apply some more math to it we get the following:

  • 3,888 / 200 = 19.4
  • 2,592 / 200 = 13

This tells us that the maximum print size for a 10 megapixel image at 200 pixels per inch - still pretty high in terms of print quality - is 13 x 20 inches.

You certainly CAN print this 10 megapixel image LARGER than 13 x 20, you just have to use less pixels per inch. And guess what? The less pixels per inch you use, the LOWER the quality of the print.

Cropping Out

Perhaps you're one of those people who just never gets close enough to your subject.

Your subjects wind up looking too small in your photos and you often want to cut out a lot the surrounding image in order to focus on your primary subject.

Another benefit to images with high megapixel counts is that you can cut out - or crop - large portions of the photo, and you'll still be able to make large prints.

For example, if I don't crop a 10 megapixel image at all, I can print at 13 x 20 inches. But if I crop out 50% of my photo - and that's quite a lot - I can still print at 6.5 x 10 inches or smaller without losing quality.

Bottom Line

If your goal is to make museum-size prints OR crop your photos aggressively, then you definitely should pay attention to the number of megapixels.

If you want to share photos in online galleries, e-mail shots to friends and make smaller prints, then don't fret too much about the megapixel count of a camera.