Adjusting aspect ratios
An image, shot with a digital camera held in normal horizontal orientation
(a.k.a. landscape orientation), has an aspect ratio of 3:4.
This means, that the picture is exactly 3/4 as high as it is wide. The image, depending on the camera's megapixel
setting, can have a size of 480x640,
600x800, 768x1024 or 1536x2048 pixels, or perhaps even more. But, no matter what the absolute size is, the aspect
ratio of the digital image will always be the same, precisely 3:4.
If a 3:4 image is shown in full screen mode on a standard computer monitor or on a regular TV set, then
the aspect ratio of the photo is the same as the aspect ratio of the picture tube. The entire image is visible,
there are no "bars" on top or bottom, and no parts of the picture get cut off.
For printed photos, however, it's a different story.
The most common size for photos in North America is 4x6 inches, having an aspect ratio of 2.67:4.
This means, that when a 3:4 image is printed over the entire width of the paper, there will not be enough space to
print the image's full height. As a result, when a digital image is printed, the picture will lose about 11% of its
original content. Most often, the picture will be centered on the paper, which causes equal portions on top and
bottom to be dropped. Occasionally the operator might shift the print window up or down, so a person's head or feet
don't get cut off.
But sometimes it might be important to keep the entire picture.
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