All Megapixel Cameras of the Same Megapixel Number are Not Identical

Any shopping excursion for cameras will reveal a wide selection of seemingly identical x-megapixel digital cameras. Unfortunately, two digital cameras of the same megapixel rating are not necessarily the same.

There are other factors which actually determine what the final resolution of your digital image will be. For a minute lets assume that we are all great photographers, the settings on our cameras are correct, and our optics are top notch. The same megapixel rating will not yield the same number of pixels.

Some manufacturers will advertise the total number of pixels on the image sensor while only using a smaller number of them for the actual image capture. The term to look for in the camera specifications is "effective pixels". This number is actually closer to the real pixel count. It is really all about the actual number of pixels outputted to your memory card that creates the final image.

That number can be very different than the actual number of sensor pixels. For example, Fuji developed a technology which they called: "FujiFilm's SuperCCD". This technology creates 6-megapixel images from 3-megapixel sensors and creates great images.

The main message to this is that when you are comparing similar cameras, read the specifications to see how the manufacturers define their pixel ratings. By doing that you will be able to compare the effective pixels which are the most accurate measure of resolution and thus image quality.

While thinking about megapixel ratings keep in mind that it is not a straight line comparison that 3 megapixels are half as good as 6 megapixels.

While 6 is a better number it does not mean that the final image can be twice as big and at the same quality.

The reason for this is that megapixels measure potential image area. That is the length of a picture multiplied by its width. For a typical 3-megapixel image with a measurement of 2048 by 1536 pixels at 300 dots per inch you could print a 5-by-7-inch print. A 6-megapixel image which is about 3000 by 2000 pixels and can print at about 7 by 10 inches. (Learn More)

The bottom line is that a simple doubling of the megapixel count does not double the size of the image.

By now you are probably saying: "Wait, I have seen great 8x10s from my 3megapixel camera!" I won't argue with that statement.

One of the advantages of digital is that images can be interpolated to increase its size. When an image is interpolated by a computer or printer it uses the information that it has available to create the extra information it needs for the image. While acceptable, this is not perfect.

Another reason you may be receiving images that are better than what this article is saying you can is that you may be printing at less than 300 DPI. I have found that on some printers a 250 dpi setting is as acceptable as 300. However, the bottom line is that these images are simply not as good as they would be with a higher megapixel camera.