What the Heck is an “Effective Megapixel”?

There are a number of digital cameras marketed this year according to their “effective megapixels.”

So what the heck is an “Effective Megapixel”?

If you think it’s a marketing gimmick, it is, but not in the negative sense that one would expect.

Actually it’s a positive thing for which all digital camera manufacturers and marketers should be congratulated.

An “effective megapixel” is the actual number of pixels which make up the viewable image captured by a digital camera.

If for example a camera has 4.5 megapixels with 4.1 effective megapixels you can safely ignore the 4.5 part. 4.1 megapixels is what you’ll actually see in a photograph.

The difference between these two concepts is expressed beautifully by this food analogy published by digicamguides.com:

Total Megapixels: This is like the full plate of food.

Effective Megapixels: This is the amount that you eat.

And did you know that the number pixels is important only with relation to the ultimate PRINT SIZE?

That is, a 2.0 megapixel camera produces pictures as sharp as an 8.0 megapixel camera if you never print anything larger than 4” x 6”, which is the standard print size in the USA.

So, if you’ll never print anything larger than 8” x 10”, you’ll never need a camera with more than 4.0 megapixels.

But the camera manufacturers of course will never tell you that in order to keep selling more expensive cameras with even more megapixels. I don’t believe the human eye can even tell the difference beyond 4.0 megapixels.

Here is a Print Chart to help you decide what kind of a camera you might need:

Megapixels -- Print Size (inches)

2.0 -- 4 x 6 [standard]

3.0 -- 5 x 7

4.0 -- 8 x 10

5.0 -- 9 x 12

6.0 -- 11 x 14

8.0 -- 12 x 16

(Source: digicamguides.com)