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Contrast ratio, on/off contrast, ansi contrast. Πολύ κουβέντα γίνεται και τα νούμερα πάνε και έρχονται. 400/1, 500/1, 1000/1, 1.000.000/1. Σκοτεινοί θάλαμοι, φωτόμετρα, έγκυροι και αναξιόπιστοι, κρυφές μετρήσεις, φανερές μετρήσεις, σκοτεινές μετρήσεις. Κοντεύουν να μας κάνουν να τρέχουμε και να μη φθάνουμε. Που άραγε να βρίσκεται η αλήθεια και που η μπλόφα ;
Θα αρχίσω με μια αιρετική κατά πολλούς άποψη. Έτσι για να ανάψουν τα αίματα.
Why We No Longer Test Contrast Ratio
Contrast ratio is a measure of the difference between the darkest possible areas in an image (read: black) and the lightest possible areas (read: white). We used to test contrast ratio for every projector, with tests based on the ANSI testing procedures. We've now dropped this test for most projectors, however.
Contrast ratio for projectors is a little like dot-per-inch ratings for printers. At one point in the history of each technology, the one specification told you a great deal about image quality. Today, both have become nearly meaningless numbers, because there are so many other factors involved.
All other things being equal, the contrast ratio will tell you how well colors pop and how well you can see details based on small changes in shading. In theory, high-contrast images look sharp and colorful; while low-contrast images look washed out and flat. In today's projectors, however, all other things are almost never equal, and the contrast ratio is only one factor among many that can give an image the same visual impact.
For example, more and more projectors are using dynamic adjustments, changing levels based on what's on the screen in any given frame. Since contrast ratio is measured with a static screen image—a checkerboard pattern of alternating full black and full white squares—the measurements have no way to take this dynamic aspect into account.
As a result, it's not at all unusual for a projector with a low contrast ratio to outdo one with a much higher contrast ratio in precisely those aspects of the image that contrast ratio is supposed to measure. Given that the contrast ratio doesn't really tell you anything today, measuring it is usually pointless. If we notice that a given projector has obviously poor contrast ratio, however, we may still measure and report it so we have a quantitative measurement to back up our qualitative observation.
Από το PC magazine.
http://mobile.pcmag.com/device/arti.../www.pcmag.com/article2/0,2817,2352865,00.asp
Συνεχίζεται...
Θα αρχίσω με μια αιρετική κατά πολλούς άποψη. Έτσι για να ανάψουν τα αίματα.
Why We No Longer Test Contrast Ratio
Contrast ratio is a measure of the difference between the darkest possible areas in an image (read: black) and the lightest possible areas (read: white). We used to test contrast ratio for every projector, with tests based on the ANSI testing procedures. We've now dropped this test for most projectors, however.
Contrast ratio for projectors is a little like dot-per-inch ratings for printers. At one point in the history of each technology, the one specification told you a great deal about image quality. Today, both have become nearly meaningless numbers, because there are so many other factors involved.
All other things being equal, the contrast ratio will tell you how well colors pop and how well you can see details based on small changes in shading. In theory, high-contrast images look sharp and colorful; while low-contrast images look washed out and flat. In today's projectors, however, all other things are almost never equal, and the contrast ratio is only one factor among many that can give an image the same visual impact.
For example, more and more projectors are using dynamic adjustments, changing levels based on what's on the screen in any given frame. Since contrast ratio is measured with a static screen image—a checkerboard pattern of alternating full black and full white squares—the measurements have no way to take this dynamic aspect into account.
As a result, it's not at all unusual for a projector with a low contrast ratio to outdo one with a much higher contrast ratio in precisely those aspects of the image that contrast ratio is supposed to measure. Given that the contrast ratio doesn't really tell you anything today, measuring it is usually pointless. If we notice that a given projector has obviously poor contrast ratio, however, we may still measure and report it so we have a quantitative measurement to back up our qualitative observation.
Από το PC magazine.
http://mobile.pcmag.com/device/arti.../www.pcmag.com/article2/0,2817,2352865,00.asp
Συνεχίζεται...
