Megapixel Myth: Do You Need More Megapixels?
The rush for more megapixels has been on for quite a few years now. More pixels are being packed on smaller (or same size) sensors every day. So what does this really mean? Do more megapixels actually mean more better quality images
It’s been a myth for a while now, that more megapixels mean better pictures! Whether on Smartphones, or on Cameras. Let’s go over some facts and see whether this is the case, or not.
Some Basics about Pixels (and Megapixels)
Let’s start with a pixel (short for picture element). A pixel is the smallest element of a digital photograph. It represents a single dot in an array that together make up an electronic image.
Let’s say that you have an image that is 800X600 pixels in size, this means that there are 800 pixels in its width and 600 pixels in its height, totally making 480,000 pixels in the image. A megapixel is one million pixels (1,000,000 pixels) and 800X600 is only 0.48 megapixels.
More megapixels do mean clearer pictures, but only when you’re printing them really big. On a computer screen at 1920×1080, a picture taken by a 2,073,600 pixel camera (2.07 Megapixels) would fill up the entire screen! On a 2048×1080 screen (2k resolution), you would still only need a 2.2 megapixel camera!
Is that interesting or what? So why do we need 13 Megapixel cameras on our phones? We’re never going to use those images for anything more than sharing on Facebook (2 megapixels maximum) or Instagram (1080px width) anyway.
I was recently looking up an entry in the photo.net forum about the maximum size prints that can be made from the Canon 5D’s pictures… and there are a lot of answers out there! Some people come up with ideas that are based on misinformation while others are just too carried away by the techie stuff. So let me give you some basics for printing images from digital files.
The Math Behind Printing
Magazines and books print at 300 DPI (Dots Per Inch) while most photo labs print at 200 DPI (a few print at 300 DPI).
Now, a regular print is about 6in x 4in which means that you need only a picture with 1,800 pixels in its width for an offset print or 1,200 pixels for a photo print. That’s not so large, given that a regular camera frame is in the ration of 3:2, which means that your ideal picture to print at 6 x 4 in a magazine need not be any larger than 1,800X1,200 pixels i.e: 2.16 megapixels.
Pixels Per Inch Vs. Drops Per Inch
But what about these newfangled “photorealistic” inkjet printers that print at 720 and 1440DPI?
Well, they don’t need anything more than 300 DPI either.
When a printer says that it is printing at 300 DPI, it actually means that it is spitting out 300 drops of ink onto a square inch of paper. 300 of those microlitre or picolitre droplets on a square inch of paper is not much, so with ‘photorealistic printing’ you need at least 1440 drops per inch (DPI) to ensure that the paper is covered completely and that you see a smooth gradation of colour even if the print is viewed from close by.
Biggest Print Size
Now, what’s the largest print that you’re going to make with your best picture?
Most people would not enlarge their prints beyond 8″X12″ which translates into about 3.8 megapixel at 200 DPI (photolab quality) or 8.6 Megapixel at 300 DPI (offset print quality).
Everyone who is going to use their cameras to illustrate a coffee table book please put up their hands… I don’t see many… 😉
My suggestion is that the people with the hands in the air buy a dSLR camera with upwards of 20 Megapixel sensors, to ensure a high enough resolution picture for their offset prints.
Everyone else can stay at below 12 Megapixels and still be happy with amazing detail in their pictures, even when enlarged, or zoomed and cropped!
Personally, I am entirely satisfied with photo printing at 200 dpi. They are sharp, clear and have excellent colour contrast.
So well then, what about the better pictures… like I’ve said earlier, it’s the photographer who can make a picture better, not the equipment. Aren’t you so much more likely to enlarge a great picture taken with a simple camera than to enlarge a drab one taken with a sophisticated one? And now you know that it doesn’t take a ridiculously high number of megapixels to get a large print, so don’t worry about the megapixels, worry about how you take the photograph.
Happy shooting Amigos!