When you crop, you are throwing away parts of the photo. This means that you're left with fewer pixels than you started with. If, for example, you started with a 6 megapixel image and cropped away 50% of the image, you'd be left with a 3 megapixel image. As we discussed, those 3 megapixels remaining would be plenty to make a good 4x6 inch print. If, however, you'd started with only a 3 megapixel image before you made your 50% crop, then you'd be left with only a 1.5 megapixel image which would not make a good quality 4x6 print.

Can You Have Too Many Megapixels?

So we've established that high megapixel cameras are useful for large prints and big crops. We've also established that having more megapixels won't be of any benefit beyond certain print sizes. But shouldn't you still try to get the most megapixels for your money? Can you have too many megapixels? Unfortunately, there are some drawbacks to having more megapixels.

First, a higher megapixel count means that the camera is trying to record a larger amount of data for each picture. The camera may take longer to write the data to your memory card, slowing your ability to take consecutive shots. More data also means larger files. With larger files, you won't be able to fit as many pictures on your memory card before you have to offload the pictures to a computer. Transferring those pictures

to your computer will also take longer with bigger files.

The other concern with high megapixel counts is the introduction of noise into pictures. Manufacturers' marketing departments understand that most people equate more megapixels with better cameras. They push hard to get higher and higher megapixel cameras out the door to keep pace with their competitors. Unfortunately, technological development can't always keep up with marketing zeal.

As manufacturers cram more and more photosites onto their tiny sensor chips, some of those photosites interfere with adjacent sites. The result is noise. Noise shows up in your pictures as little off-color dots. I've included a rather extreme example of image noise below.

Click for full size

Notice all the off-color red, blue, and green pixels? The speckled, grainy look absolutely kills the image quality of this picture. Some high megapixel cameras struggle more with noise than others, so be sure to examine sample pictures from any camera you're considering purchasing.

<< Return to page 1 | Continue to page 3 >>

Page « Previous 1 2 3 Next »