What is the relation between megapixels and maximun enlargement size
The number of pixels (measured in megapixels only because there's so many of them, the number would be very long if they didn't shorten it down; much like saying gigabyte for hard drives, instead of bytes) directly correlates to how much data has been recorded for a particular image.
Photos aren't "drawn" with lines (which is known as a vector image). They are recorded in pixels (raster image), and each pixel is just a single dot of a single color at a specific place in that photo.
When you look at that photo at a very small size (such as on your monitor), the computer "interpolates" (a fancy word for "guesses") which pixels to hide from view, and kind of remixes the other colors on the screen so it looks like the original photo. (Kind of weird, but it's true.)
The photo is "perfect" when it is the full size (one pixel on-screen to one pixel in-photo ratio). No interpolation is done, so you see exactly what you photographed.
If you enlarge a photo beyond the number of pixels you have, you again have to do interpolation, where the computer has to "guess" which color pixels would blend properly between the real pixels in the gaps that are created when it's stretched beyond what data is there.
So, to answer your question:
The direct relationship is this: If you have too few pixels (as rated in megapixels), and you enlarge the photo too much, then there's too much guesswork done by the computer. It is just kind of filling in colors, and this makes the photo look blurry. It can't create detail where no detail existed before.
The more pixels you have, the larger the print you can make WITHOUT enlarging (or interpolating) it. This makes the result very crisp indeed, because all of the pixels are coming from the photo, not from the guesswork of the computer. Even if you are only enlarging it a small amount, it's going to be infinitely better than enlarging it a larger amount. The more interpolation, the fuzzier it gets.
Oct 02, 2014 |
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