If you only enjoy your
photos on your
computer screen, or
uploading to a photo
website to share with
friends, you really only
need a 1 megapixel
camera. That is
because your computer
monitor is usually about
1000×1000 pixels = 1
megapixel! I’d err on the
safe side and use a 3
megapixel camera or
higher to enable
cropping though, as I
discuss below.
When you print your
images, you will need
more megapixels. If
your megapixel count
isn’t enough for the
size of image you print,
your images won’t look
sharp.
Use the above table as
a guide for the number
of megapixels you need.
Notice how I say
“14×11 inch prints or
larger” on the last line
of the table. You only
really need a 7
megapixel camera for
any prints larger than
14×11. Even huge 30×40
posters. That’s
because we normally
stand further away
from larger prints, so
we don’t notice when
they are less sharp!
Why you might
need more
megapixels
There are a few
reasons why you might
want to buy a camera
with more megapixels
than that listed in the
table above. The most
important is cropping.
Sometimes you don’t
always capture what
you want to capture in
the right part of the
frame. If you crop the
image slightly, it looks a
lot better than it would
if you just left it alone.
This is the main
advantage of having a
camera with more
megapixels. It gives you
a little extra room to
play around with when
you are cropping your
photos.
But how much room do
you really need? If you
were to double the
image size, that would
be more than enough
room to crop photos
and still have a great
looking image on your
monitor screen. Now for
a 6×4 print, we are up
to 4 megapixels.
The other main reason
is for the times when
you take a photo you
are really proud of. You
will want to print it as
large as possible to
show it off! This is
where having taken the
shot with a 6
megapixels camera can
really help!
The Megapixel
Marketing Myth
But wait, I hear you
say, these are incredibly
small numbers! Why do
camera makers keep
making cameras with
many more megapixels
every year? The
answer is simple. They
need a reason to
convince us in the public
that the next model we
buy will be a big upgrade
from the one they we
now. What better way
to do it than with a
number that steadily
increases as camera
makers make bigger
sensors every year?
So, what is the lesson
to be learned from all of
this? Megapixels are
great. They brought
digital photography out
of the dark ages and
allowed photographers
to make digital images
that compare to film
images. But megapixels
are no reason to
upgrade your current
model. Instead, focus
on a kind of image you
would like to get and
consider the limitations
of your current camera
model. You might need a
different lens or a
camera body that takes
a quicker continuous
stream of photos. If
you do end up buying a
new camera body, do it
for reasons other than
the fact that you will be
getting more
megapixels with it

source:www.digital-photo-secrets.com/tip/333/do-more-megapixels-mean-better-photo-quality/