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Old October 18th 12, 12:31 AM posted to rec.photo.digital
Rob
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Posts: 236
Default Megapixels - An Explanation of Megapixels and How They AffectPhotos

On 17/10/2012 5:27 PM, Abigail1 wrote:
Camera manufacturers are fond of advertising cameras by the number of
megapixels they have. But what exactly is a megapixel and how does it
affect photos?

A megapixel is 1 million pixels. Pixels are small squares that are put
together like pieces of a puzzle or mosaic to create your photographs.
The resolution of your image will be determined in large part by how
many of these tiny squares are packed together in a small space.

An 8 megapixel camera (8MP) would have roughly eight million tiny
squares of information per inch while a camera phone at 1.5 megapixels
(1.5MP) would only have one and a half millions squares of information
in an inch.

So what does that mean for your photos?
Simply put, the more information the better. The more information
squeezed into an area, the better our eyes blend the edges together to
create a complete image. If too little information is available the eye
will notice the jagged edges of the pixels where they meet, just as you
see the individual squares of mosaic tile designs. The accepted
"standard" for printing images is currently 300dpi (dots per inch).
While dots per inch aren't technically the same as pixels per inch the
difference won't affect you in your day to day photo taking/printing.

How much information do I need?
To figure out how much information you need for a specific print size
all you need do is multiply the print size by the resolution desired.
For example, with the 300dpi rule in mind, to print an 8x10 photo you
would need 2400 pixels by 3000 pixels of information. If you were
displaying an image on the internet (where 72 pixels per inch is
acceptable) you would only need 576 pixels by 720 pixels.

So how many megapixels do I need?
Each camera displays data in slightly different ratios but there are
some "rules of thumb" you can follow. Decide what the largest size image
you will want to print. For most people this will be an 8x10 image.
Determine the number of pixels needed for a 300dpi print (2400x3000 for
an 8x10). Next multiply the two pixel dimensions together. For an 8x10
this comes out to 7.2 million pixels, or 7.2 megapixels. This is the
preferred number of MP you need if an 8x10 print is the largest you are
likely to print.




Where did you get that garbage from?