What is an “Effective Megapixel”?
Introduction
There are a number of digital cameras marketed this year according to their “effective megapixels.”
So what the heck is an “Effective Megapixel”?
Definition of Effective Megapixel
Effective Megapixel is the number of megapixels that a camera sensor has to produce an image of a given size.
The term “megapixel” is used in photography to measure the number of pixels in an image. It’s not just about the number of pixels, but also how much detail is captured by each pixel. The more megapixels, the more detail you will be able to capture in your photo.
Why It’s Important
The reason why this number is important is that it gives the photographer more control over how much detail they want to capture in their photos. For example, if you are taking photos for social media, you might not need as many megapixels as someone who takes photos for print or film.
Effective Megapixel is an important metric when comparing cameras because it determines how much detail the camera will be able to capture.
How Effective Megapixel is Measured
Megapixels are measured by square units and not linear units like inches or centimeters.
This means that a 36-megapixel camera will have 3 times as many pixels as a 12-megapixel camera, but it will take up 6 times less space on your hard drive than the 12-megapixel camera because it has smaller pixels.
The term “effective megapixel” was coined to describe how many megapixels a camera would have if it used different-sized sensors. This is important because different sized sensors can produce images with very different qualities, even though they may have the same number of megapixels.
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.
An Analogy to Understand Effective Megapixels Better
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 of pixels is important only in 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.
Print Chart
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)
Conclusion
Effective Megapixel is an important metric when comparing cameras because it determines how much detail the camera will be able to capture.
