Why is it that the good folks who advertise cameras [and cellphones] keep telling us how many megapixels everything has? And why do they all keep coming up with bigger and bigger numbers every year?
Is that megapixel number the most important thing to keep in mind when buying a new camera?
They keep throwing that number around because somehow the majority of the population has come to think that it is the number of megapixels that makes a great image.
It’s not the megapixels alone, in fact that number isn’t as important as we are lead to believe.
First of all what is a megapixel anyway?
A pixel [picture element] is a unit of color on a computer display or in a digital image. It’s not really a physical unit with a set size as it’s size depends on your image’s resolution [the size of the camera’s sensor]. Think of it like one piece of a puzzle or one small tile in a large mosaic.
A megapixel is the equivalent of one million pixels.
How many megapixels do you really need?
Well; that depends on how you are going to use your images…
If you are simply viewing your images on your computer monitor or sharing on your favorite social media site you really only need 1 to 3 megapixels. Printing a standard 4″x6″ print? You can get away with 2 to 4 megapixels easily. Bump that up to 5 or 6 megapixels for an 8″x10″ print and up to 7 or 8 for a 14″x11″.
There are reasons why you might want a camera with more megapixels; the most important being cropping. Once in a while you capture a wider view than you want to share and you will need to crop away the unwanted background. Those extra megapixels give you room to play and usually just doubling them is enough. Say for that 4″x6″ print you might want to start with a 4 to 8 megapixel camera and for that 14″x11″, to be safe, a 14 megapixel camera should do the trick.
Another reason you might want to use a larger megapixel camera is if you’re planning to make really large prints say wall size; or billboards! Or if you are a professional photographer and need to capture as much information as you possible can before sending those photos off to be used in any number of ways; including those billboards.
Remember when I said it’s not megapixels alone?
Just because two cameras have the same number of pixels, doesn’t mean that the size of their pixels are the same. The difference between a more expensive DSLR and a compact camera [or your cell phone] is that the DSLR has a much larger sensor area. This means that if both the DSLR and compact camera have the same number of pixels, the size of each pixel in the DSLR camera will be much larger. It also means that if your compact has more pixels than the other guy’s DSLR his pixels will actually capture more information than yours because he has a much larger sensor area.
The megapixels in your camera are only as good as the sensor in your camera. The size of the sensor determines how much light it uses to create your prized images. The sensor is made up of millions of tiny light-sensing dots called photosites. Those photosites record the information about what you see through your lens. A bigger sensor can capture more information than a smaller one and therefore produce a better quality image. A bigger sensor means bigger photosites those bigger photosites mean your megapixels are able to gain more information. More information means better image quality.
The megapixel debate is a loaded one for photographers. Many argue that no pro-photographer really needs more than 18 megapixels and others say that the added detail out weighs the extra noise and extra computer processing power needed to work with those extra huge files.
Finding the perfect camera for your needs is a complicated balancing act between the megapixels, the sensor size and processor, the build of the body, the quality of the lenses you choose, and your own ability to make all those things work together.
Yes; megapixels are a great thing; they have moved digital photography into the light [bad pun] and out of the dark ages and allow us to take images that compare to, and even in some cases, surpass, film images. However don’t fall victim to the megapixel myth and purchase a camera based on those numbers alone. Take the time to think about what images you will be taking and what you will ultimately do with those images. It could be you don’t need as many pixels as you thought; you might just need a faster lens, a better body [camera body], or a bigger sensor.
Do a little homework before spending big bucks on big megapixel numbers alone.