Google analytic

Wednesday, 23 January 2013

Digital Photography - What Are Pixels and How Many Do You Need?


One of the confusing things about choosing a digital camera is trying to decide how many mega-pixels you need. The number of mega-pixels is one of the major selling points camera manufacturers use in their marketing efforts. But before you can make an intelligent choice, you first must understand what a mega-pixel is and how it is used in digital photography.
What is a pixel?
Short for Picture Element (yes, I know there isn't an "x" in Picture Element), by definition a pixel is "a single point in a graphic image". So when you display a digital image on your computer screen, it is made up of millions of these single points arranged in rows and columns. These single points or pixels are so close to each other that they appear as connected and thus form an image. When an image is made into a print, these pixels are converted into dots per inch. While there is a correlation between pixels-per-inch and dots-per-inch, they are not the same.
Actually each pixel is capable of producing a range of colors from the red, green and blue dots that each pixel is capable of producing.
All pixels are not created equal.
Generally speaking a sensor in 12 mega-pixel Digital SLR (DSLR) camera for example is physically larger than the sensor in the same size digital compact point and shoot. So how can both have 12 million pixels? Each pixel in the DSLR is physically larger. The larger the pixel, the more light it will let in over a given period of time, thus making its signal-to-noise ratio higher, which in turn makes for a smoother and sharper image. Will you be able to see the difference on a computer monitor? Most likely not. So where does the difference show up?
The answer is depends on what you plan on doing with the finished images. And what you plan to do with the finished images should be a deciding factor as far as what kind of camera you need and how many mega-pixels it should have.
The effect on print size
So when camera shopping, first have in mind the size of prints you are most likely to have made from your digital images. Actually a one mega-pixel camera is fine for images you do not plan to print, but just display on a computer monitor. Of course, you can't buy a new one mega-pixel camera anymore. My point is if you are going to just display images on a computer monitor, such as on an online photo sharing website, then you can get by with a smaller mega-pixel camera - probably a compact point-and-shoot. However, if you plan to make a coffee-table photo book, then you will be most likely better off (and happier with your prints) if you use a DSLR.
Where you will really notice the difference between camera pixel size is if you make extremely large prints, such as 16" x 20" or larger. Even though both cameras have the same mega-pixel rating, when you try to spread the smaller pixels from the point-and-shoot over a large area, each pixel gets more blurry than if you would take the larger pixel from the DSLR and do the same thing with it.
So what does all this mean to the consumer-type shooter? When camera shopping, know what you are going to do with your finished images. Instead of focusing on mega-pixels, look for other features that you want and can use, such a 1080 HD video, white balance, shutter and aperture priority, image stabilization, interchangeable lenses, hot shoe, etc.
The bottom line is don't let a camera salesman talk you into a high-priced, large mega-pixel DSLR camera when one with a lesser amount of mega-pixels, but still with the features you use, will suit your needs.
posted by

No comments:

Post a Comment