From:
http://www.kenrockwell.com/tech/mpmyth.htm
INTRODUCTION
Forget the silly debate over pixel counts among digital cameras.
There is little visible difference between cameras with seemingly different ratings. For instance, a 3 MP camera pretty much looks the same as a 6 MP camera, even when blown up to 12 x 18!" I know because I've done this. Have you? NY Times tech writer David Pogue did this here and here and saw the same thing - nothing!
Joe Holmes' limited-edition 13 x 19" prints of his American Museum of Natural History series sell at Manhattan's Jen Bekman Gallery for $650 each. They're made on a D70.
There are plenty of shows selling shots from fuzzy Holgas for a lot more money, just that those folks don't tell me about it. Holgas sell for $14.95, brand new, here. You can see an award-winning shot made with a Holga hanging in Washington, D.C.'s Hemicycle Gallery of the Corcoran Museum of Art in their 2006 Eyes of History competition of the White House News Photographers Association here.
Resolution has little to do with image quality. Color and tone are far more important technically. Even Consumer Reports in their November 2002 issue noted some lower resolution digital cameras made better images than some higher resolution ones.
PIXELS, RESOLUTION and PIXEL COUNT (MEGAPIXELS)
Pixels
Images are made up of little dots called pixels. Pixel stands for PICture ELment. Put enough of them together and you have a picture. They are arranged horizontally and vertically. Get close enough to your computer screen (or use a magnifier) and you'll see them.
Resolution (Linear Resolution)
Image Resolution
Resolution is how many pixels you have counted horizontally or vertically when used to describe a stored image. Digital cameras today have between 2,048 and 4,500 pixels horizontally. 3 MP cameras have 2,048 pixels horizontally and 14 MP cameras have 4,500 pixels. They have fewer pixels vertically since the images aren't as tall as they are wide.
That's not much of a difference, is it? That's the whole point of this article. I'll explain that a little further down.
Print Resolution
Resolution is also how many pixels you have per inch or other linear unit when you print on paper. Most prints are made at 200 - 300 pixels per inch (PPI or DPI, dots per inch). This is the image resolution and has nothing to do with the technology by which the print is made. (For instance, inkjet printers' nozzle sizes are the silly 2880 DPI or other numbers you see. These printer numbers are often used by hucksters to hoodwink and distract you when talking about resolution. These only refer to how the ink is spat out on the paper.)
Screen Resolution
Most computer screens today are about 100 DPI, dots per inch. There isn't much variation from screen to screen so we rarely discuss this. It's easy to figure out: most computer screens are about 1,024 x 768 pixels. If your screen is 10" wide then divides 1,024 by 10 and you have a 102.4 DPI screen. Bigger screens tend to have more pixels, for instance, my 22" CRT has 1,600 x 1,200 pixels and has a viewing area of 16 x 12."
Yes, laptops with bigger screens tend to have lower linear resolution. No big deal.
Pixel Count, expressed as Megapixels
Pixel Count, expressed as Megapixels, is simply multiplying the number of horizontal pixels by the number of vertical pixels. It's exactly like calculating area. A 3 MP camera has 2,048 (horizontal) x 1,536 (vertical) pixels, or 3,145,728 pixels. We call this simply 3 MP.
Small differences in pixel count, between say 5 MP and 8MP, are unimportant because pixel counts are a square function. It's exactly like calculating area or square footage. It only takes a 40% increase in linear dimensions to double the pixel count! Doubling pixel count only increases the real, linear resolution by 40%, which is pretty much invisible.
THE MYTH
The megapixel myth was started by camera makers and swallowed hook, line and sinker by camera measurebators. Camera makers use the number of megapixels a camera has to hoodwink you into thinking it has something to do with camera quality. They use it because even a tiny linear resolution increase results in a huge total pixel increase, since the total pixel count varies as the total area of the image, which varies as the square of the linear resolution. In other words, an almost invisible 40% increase in the number of pixels in any one direction results in a doubling of the total number of pixels in the image. Therefore camera makers can always brag about how much better this week's camera is, with even negligible improvements.
This gimmick is used by salespeople and manufacturers to you feel as if your current camera is inadequate and needs to be replaced even if the new cameras each year are only slightly better.
One needs about a doubling of linear resolution or film size to make an obvious improvement. This is the same as a quadrupling of megapixels. A simple doubling of megapixels, even if all else remained the same, is very subtle. The factors that matter, like color and sharpening algorithms, are far more significant.
The megapixel myth is also prevalent because men always want a single number by which something's goodness can be judged.
Unfortunately, it's all a myth because the number of megapixels (MP) a camera has has very little to do with how the image looks. Even worse, plenty of lower MP cameras can make better images than poorer cameras with more MP.
THE PROFIT-DRIVEN HYPE TO MAKE YOU PAY TOO MUCH
Here's a complete fabrication by a company who is trying to spread the myth to get you to buy too much camera. There's a similar page here. That page is brilliantly done, however it's done with completely incorrect data to exaggerate the differences. At the low magnifications shown on the screen any and all of those examples should look perfect. Instead the two lower resolution examples have been severely degraded. Their page displaying results for a 5 x 7" print actually show how the 4 MP camera would look blown up to 12 by 9 feet, not 5 x 7 inches!...
.... read complete article here:
http://www.kenrockwell.com/tech/mpmyth.htm
So, what do you think??
The Megapixel MYTH
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