Nothing’s super about superfluous pixels

Nothing’s super about superfluous pixels
If you think you can never be too rich, too thin, or have too many megapixels,
think again. Megapixels have a dark side, too, Luke. Unnecessary pixels
lead to bigger image files, usefulewhen you actually need all those pixels, but
they’re a potential nuisance if you don’t. Few people have the problem of
being able to afford a camera that has a resolution significantly higher than
they really need, but if you’re in that elite class, consider these caveats:

1. Excess megapixels eat up your memory cards. All dSLRs store images on
solid-state memory cards. I own three cards for my 10MP camera, each of
which can store about 272 pictures in the best high-resolution shooting
mode. Most of the time, I have plenty of digital film for any day’s shooting,
and I can always drop to a lower resolution mode to stretch my memory
cards further. However, if I used the same vendor’s top-of-the-line 24.5MP
dSLR, each of those cards could hold only 85 images at the top quality setting.
I’d have to own a lot more memory cards to do the same work!

2. Extra resolution taxes your computer. Fat photo files take a long time to
transfer to your computer, and your image editor needs fast processing
speeds and a lot of memory to manipulate those files. That high-end digital
camera that you’re lusting after might call for a high-end computer, too.

3. More pixels need more storage. Very high-resolution files can be several
times larger than your run-of-the-mill high-resolution image files. If
you want to keep a lot of these files available on your hard drive, you
need a large disk — and probably a lot of extra CDs, DVDs, or external
hard drives to which you can archive them for permanent storage.

Article From : Digital SLR Cameras and Photography For Dummies 3rd Ed. (Book)