fiftyonepointsix Posted July 26, 2015 Share #81 Posted July 26, 2015 Advertisement (gone after registration) The compression scheme (compressed DNG) of the M9 is identical to that of the M8. The 14-bit values are converted to 8-bits by first multiplying times 4 and then taking the square root. This produces an 8-bit value. Uncompressed DNG stores full values, no compression is used. It is the M240 that moved to a lossless compression scheme. Link to post Share on other sites More sharing options...
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mjh Posted July 27, 2015 Share #82 Posted July 27, 2015 The compression scheme (compressed DNG) of the M9 is identical to that of the M8. The 14-bit values are converted to 8-bits by first multiplying times 4 and then taking the square root. This produces an 8-bit value. Uncompressed DNG stores full values, no compression is used. It is the M240 that moved to a lossless compression scheme. Exactly. And taking the square root of a 14 bit value would yield a 7 bit value, not a 12 bit one. There is nothing to suggest that the M Monochrom (Typ 246) employs anything like the square root compression scheme of the M8 and M9. Neither did the original M Monochrom, by the way, as that kind of lossy compression isn’t suited to monochrome data. There was little advantage (if any) to saving uncompressed data with the M9 but the MM was different. Link to post Share on other sites More sharing options...
CheshireCat Posted July 27, 2015 Share #83 Posted July 27, 2015 Exactly. And taking the square root of a 14 bit value would yield a 7 bit value, not a 12 bit one. There is nothing to suggest that the M Monochrom (Typ 246) employs anything like the square root compression scheme of the M8 and M9. Tell Erwin. Link to post Share on other sites More sharing options...
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