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PIXSultan | profile | all galleries >> Technology, Development & Tests >> Canon 20D/30D/5D/1D/1Ds/MKII/N/III tree view | thumbnails | slideshow

Canon 20D/30D/5D/1D/1Ds/MKII/N/III

Testing 1D2/1D2n/1D3 output and results with FLEXSharp, FLEXTone, etc. Samples obtained from other users in DPReview, and other resources.
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Screen_ShotSharpening_Defects-1.jpg
Screen_ShotSharpening_Defects-1.jpg		 _D6H5068.JPG
_D6H5068.JPG		 Screen_Shot1DMKII_vs_20D-JPG-FLEXS_mRadius-c.jpg
Screen_Shot1DMKII_vs_20D-JPG-FLEXS_mRadius-c.jpg		 Screen_ShotDR-1DsMKII_20D-1.jpg
Screen_ShotDR-1DsMKII_20D-1.jpg
SCREEN_SHOT1DMKII_5D_DR_JPG-1.jpg
SCREEN_SHOT1DMKII_5D_DR_JPG-1.jpg		 SCREEN_SHOT1DMKII_5D_DR_JPG-2.jpg
SCREEN_SHOT1DMKII_5D_DR_JPG-2.jpg		 SCREEN_SHOT1DMKII_5D_DR_RAW-1.jpg
SCREEN_SHOT1DMKII_5D_DR_RAW-1.jpg		 SCREEN_SHOT1DMKII_JPG_vs_EVU-1.jpg
SCREEN_SHOT1DMKII_JPG_vs_EVU-1.jpg
SCREEN_SHOT1DMKII_JPG_vs_EVU-2.jpg
SCREEN_SHOT1DMKII_JPG_vs_EVU-2.jpg		 SCREEN_SHOT5D_JPG_vs_RIT-2.jpg
SCREEN_SHOT5D_JPG_vs_RIT-2.jpg		 SCREEN_SHOT5D_JPG_vs_RIT-1.jpg
SCREEN_SHOT5D_JPG_vs_RIT-1.jpg		 SCREEN_SHOT1DMKII_5D_DR_JPG-3.jpg
SCREEN_SHOT1DMKII_5D_DR_JPG-3.jpg
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Norman Koren 25-Nov-2005 18:27
I have made a change to Imatest in version 1.5.5 that affects dynamic range (DR) measurements made with the Stouffer T4110 transmission chart. I have realized that the "indistinct zones" (dark zones where edges between them are not clearly detected) represent valid data. I wasn't sure at first. As a result I have changed Imatest output to report the dynamic range with the indistinct zones as "Total dynamic range," and I changed the former (total) dynamic range to "DR distinct steps only."

This only affects the Total dynamic range display measured with the T4110, where "indistinct zones" are present. It does not affect the DR at the various quality levels (high,...), which may be the best indicators of useable DR.

I am upgrading the documentation to reflect a number of things I've learned. Some publications report the inverse of the f-stop noise as signal-to-noise ratio (SNR). The ISO 15739 noise standard has an extrapolated DR measurement whose intent is to find the dynamic range where SNR = 1, corresponding to "low quality" in Imatest. The ISO measurement, which uses a reflective target with a density of 2, is much less accurate than the Imatest/T4110 technique.

My apologies for the confusion this has caused and is likely to cause in the near future. It will make things clearer in the long run.
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