Tuesday, June 26, 2012

The MegaPixel Myth

When Nikon announced the new D800 with 36 megapixels, the camera community collectively peed themselves like an over-excited chihuahua.  I would have liked to have been inside the boardrooms at Canon to hear them barking (in Japanese, which I imagined sounded like a cool old Kung Fu movie) to the engineers that Canon must now roll out a camera with more pixels than the D800.

Despite the interesting drama it creates, this over marketing about resolution smells worse than my son's overly filled diaper.  A visitor to my blog asked me what is the advantage to having a camera with large pixel resolution.  I began thinking about it, and decided that there are some advantages, but not as many as they'd like for you to think.

The advertising wants us to believe that more resolution is better than a camera with slightly less.  The first analogy that came to mind is with cars and horsepower.  Guys with cool cars always want more horsepower.  The new 2013 Corvette ZR1 advertises 638 horsepower that will take you whizzing along the highway at over 200 mph.  Not many people have a need to go 200 mph.  The guys who buy this car will probably not drive 200 mph very often... but it's just cool knowing that is what you have.

When it comes to cameras, the pixel resolution is important when we want to print an image, and we want it to look realistic.  The image is made up of little dots... millions of them.  Just like your television screen, the more resolution, the smoother the picture, and higher quality.  The bigger the finished picture is going to be, the higher resolution you'll need.

So how many pixels do you need to make really good looking prints?  I recently made a print at 12" x 18" and it looked beautiful. You'd need a magnifying glass to determine if it was from film or digital.  I didn't use my good Nikon cameras... I used my Android smartphone with a 3megapixel camera.  David Pogue, a writer with the NY Times made prints with low resolution cameras and put them side by side with high resolution cameras and challenged people in Times Square to try to tell a difference.  They couldn't do it.

So you don't need high resolution 15 megapixel cameras to make beautiful poster size prints.  So what's the advantage?  Cropping.  If you want to crop a small portion of an image, you can do it without worrying about the resulting print being pixelated (where you can see the dots).

For example, here's a behind-the-scenes picture from a photo shoot I had.  We were setting up lights, and I took the picture when the model made an interesting pose.
The camera that I was using is a Nikon D3100 with 14 megapixels.  The original dimensions of this picture was 4608 pixels by 3072 pixels.  At that resolution, I can crop out a small part of the picture, and then resize it to make a print.
To make this example, I created two versions of this file.  The original at 14 megapixels, and then a really small one at 1 megapixel. (I don't think I've seen any 1 megapixel cameras in a while, but this is an extreme example to make a point)
The above picture is too pixelated to make a useful print.  It's still not bad, but it's more fuzzy and jagged than most people want from a crop.
This is the crop from the 14 megapixel image.  It's still sharp enough that I could make a beautiful 8x10 print from it.

The moral of the story is that the higher resolution is just a marketing ploy to make you think that you need it to make better pictures, and so that Nikon and Canon can get more money from you.  If you already have a camera with 10 megapixels or more, you've got plenty of horsepower.  Just keep shooting.


  1. Ha! I knew it! My daughter signed up for a basic photography class required for her degree major, and they were telling her she needed to buy a digital camera with a 12.5 megapixel or higher resolution. No, her major is not photography. I thought they were full of...er, um, well, a little overzealous in their requirement for a basic photography class.

    1. I can't imagine a school *REQUIRING* you to purchase a 12mpx camera. (Although most of the new entry level DSLR cameras are at that level now). Even the little point and shoot cameras like the one I bought for my step-son last year has the same resolution as my professional-grade Nikon DSLR.

      The only logical thing I can think of is maybe the teacher wanted the assignment photos to all be the exact size so that all the students are on a level playing field when it comes to the grade... but even that logic doesn't hold up, because like I said, it has nothing to do with the quality of the image.


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