Jalaj P. Jha Technical & Miscellaneous Ramblings

How Many Megapixels Digital Camera You Actually Need?

How many Megapixels Digital Camera should I buy? This is a question mostly asked by people going in for purchase of a Digital Camera, and you know what's the common answer he gets? "The latest ones are 12 megapixels and you should prefer those over 10 megapixel" etc. Numbers can be misleading!! Don't these numbers make you feel that 12 megapixel cameras are 20% more advanced and capable than 10 megapixel? They really aren't... to know why read later in this article!

It was January 2003 when I purchased my first Digital Camera. In a town with population around two hundred thousand, I was perhaps the first person (apart from one or two photo studios) who possessed a Digital Camera. It was a decent camera with configuration above the entry level cameras of that time. It was a D-Link branded VGA Camera! VGA camera in terms of megapixels is 0.3 megapixel!! (The largest configuration available in market, at that time, was less than 3 Megapixels). Was the configuration of my camera enough?

Dwij - Photo taken from a VGA Camera

"Enough" is a measure that depends on what your requirements are, and what is delivered. This configuration was enough for me for as my basic requirement with camera was getting a picture large enough to be set as wallpaper. A VGA camera delivers an image of size 640x480 and 14" monitors in those times were generally set to 800x600 resolution. A 640x480 image stretched to 800x600 did not reveal any degradation in picture quality. At that time there were only a small number of studios in large cities that provided services for printing digital photos so that was not in my agenda.

Now let's get familiar with what megapixels mean. Mega means 'a million' and Pixel is 'a dot' the basic building block of digital pictures. A large number of dots of different colors group to make a picture. A 640x480 picture would be a picture where length would be 640 pixels and breadth 480 pixels and total number of pixels would be 640x480=307200 or nearly 0.3 millions and hence 0.3 Megapixels. Similarly 1280x1024 would be 1.3 Megapixels.

12 Megapixel and 10 Megapixel cameras thus deliver the largest images of 4000x3000 and 3648x2736. You can see that while 12 seems 20% larger than 10, the length and breadth of the pictures don't actually increase 20% each. Overall it may not help you much in your photo prints. So your basic criteria for Camera selection should be the quality of the picture it captures and not megapixels. A 10 megapixel camera delivering good photo quality compared to12 megapixel camera would be a better choice!

Why do we need higher resolution images for printing compared to those for wallpapers etc.? The reason is number of Dots Per Inch (DPI). While a screen typically has 72-96 dots placed side by side within an inch, good quality printout requires 300 DPI or above. Secondly, while the screen sizes typically limited to tens of inches, the prints can be as small as 6x4 inches prints to large posters, thus larger the image better may be the output. For example if you need to have a 8"x11" print on 300 DPI printer an image of size around 2400x3300 can give you a good printout. Though this doesn't mean that you won't get a proper printout if your camera is of lower resolution. In such cases the image automatically gets stretched to required size interpolating the missing pixels. This too can give you a good quality print with very little noticeable difference with high resolution image print.

Hope this helped you!!