What is a megapixel?

Megapixels are interesting things. To get to the answer to the trivia question. A megapixel is simply 1 million pixels. If you want to be pedantic, we will also accept 1,048,576 pixels. But in general, we have all agreed ~1 million pixels is a megapixel.

An example for that in the wild is my EOS M6. It takes photos that are 6000×4000. If we do the math, that makes 24,000,000 pixels, so it is a 24 megapixel camera. And really, for most things, that’s overkill. To give you an idea… if you wanted to make an 8×10 print at 300dpi (really nice quality), that would translate to 300×8 =2400 and 300×10=3000. Now, we take 2400×3000 and find that it requires 7.2 megapixels.

Perhaps more telling, if you are running on a 1920×1080 monitor, that is just over 2 megapixels. Even if you have a new 4k monitor running at 3840×2160. That’s 8.3 meagpixels.

So why do we have 24 megapixel cameras? 60 megapixel cameras? For one, marketing. 24 megapixels sounds a lot better than 12 megapixels. There is also the ability to make really big prints. I just did a 16×20 print. At 300dpi, you are hitting 28 megapixels.

And there is downsampling. In short, if I take that 24 megapixel image and downsample it to 2 megapixels to fit a monitor, there are benefits to be had. Just as anything in the photo appears smaller when you downsample, any noise in the image is also reduced. The effect is what appears to be a cleaner and sharper photo.

But the moral of the story is that you probably don’t really need as many megapixels as you have available. That photo at the top of this post started out at 24 megapixels, but if you view it full size, it is now 2.2.

There are times where you do need more megapixels though. Which brings us to today’s photo. That is my first digital camera. The JamCam 3.0. It outputs .3 megapixels. That is a 640×480 image. And if memory serves, they are terrible. If I can dig up a 9 volt, I might fire it up and get some 2020 examples.

It’s interesting to look at our IT gear in the context of digital cameras, because they have traveled a similar path over the last couple decades. Just as with the JamCam, the performance of our servers from 20 years ago are almost laughable at this point. And what we can do with current models is often amazing.

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