They're getting better every year. Camera makers and your local Best Buy salesman are always talking about the next model with more megapixels than the one that came before it. The new numbers make your current model seem obsolete. If you bought a camera with six megapixels a few years ago, you wish you could get a new one that gets twelve. But does it really mean anything? Does having more megapixels amount to better photo quality, or is it all just marketing hype?
Up to a certain point, megapixels do matter. The first digital camera models had horrible resolution. They simply didn't compare to film cameras in terms of image quality. Every picture you took looked pixelated and blocky. I remember my first digital camera. It was a Sony Digital Mavica. I got a whopping half of a megapixel out of that camera, and it was considered revolutionary at the time.
What are Megapixels?
So what are megapixels, and how do they relate to image quality? To put it simply, a single megapixel amounts to exactly one million pixels in an image. If you know the width and height in pixels of an image created by your camera, it's easy to calculate how many megapixels your camera gets. In the case of my Digital Mavica, I simply multiply 640 by 480 to get 307,200 pixels total. So I guess I was wrong. My first digital camera got 0.3 megapixels.
How Many Megapixels do I need?
How many megapixels you need depends on the how you are going to use your images. Here are some common uses:
|Viewing On||Megapixels Needed|
|Computer Monitor / Online||1-3 megapixels|
|6x4 prints||2 megapixels|
|10x8 inch prints||5 megapixels|
|14x11 inch prints or larger||7 megapixels|
If you only enjoy your photos on your computer screen, or uploading to a photo website to share with friends, you really only need a 1 megapixel camera. That is because your computer monitor is usually about 2000x1000 pixels = 2 megapixels! 4k monitors still only have 8 megapixels. I'd err on the safe side and use a 6 megapixel camera or higher to enable cropping though, as I discuss below.
When you print your images, you will need more megapixels. If your megapixel count isn't enough for the size of image you print, your images won't look sharp.
Use the above table as a guide for the number of megapixels you need. Notice how I say "14x11 inch prints or larger" on the last line of the table. You only really need a 7 megapixel camera for any prints larger than 14x11. Even huge 30x40 posters. That's because we normally stand further away from larger prints, so we don't notice when they are less sharp!
Why you might need more megapixels
There are a few reasons why you might want to buy a camera with more megapixels than that listed in the table above. The most important is cropping. Sometimes you don't always capture what you want to capture in the right part of the frame. If you crop the image slightly, it looks a lot better than it would if you just left it alone. This is the main advantage of having a camera with more megapixels. It gives you a little extra room to play around with when you are cropping your photos.
But how much room do you really need? If you were to double the image size, that would be more than enough room to crop photos and still have a great looking image on your monitor screen. Now for a 6x4 print, we are up to 4 megapixels.
The other main reason is for the times when you take a photo you are really proud of. You will want to print it as large as possible to show it off! This is where having taken the shot with a 6 megapixels camera can really help!
The Megapixel Marketing Myth
But wait, I hear you say, these are incredibly small numbers! Why do camera makers keep making cameras with many more megapixels every year? The answer is simple. They need a reason to convince us in the public that the next model we buy will be a big upgrade from the one they we now. What better way to do it than with a number that steadily increases as camera makers make bigger sensors every year?
So, what is the lesson to be learned from all of this? Megapixels are great. They brought digital photography out of the dark ages and allowed photographers to make digital images that compare to film images. But megapixels are no reason to upgrade your current model. Instead, focus on a kind of image you would like to get and consider the limitations of your current camera model. You might need a different lens or a camera body that takes a quicker continuous stream of photos. If you do end up buying a new camera body, do it for reasons other than the fact that you will be getting more megapixels with it.
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