Hello,
> below follows the patch for adding noise profiles for the "Olympus E-P5" to
> darktable. The non-native reduced ISO 100 as well as ISOs above 12800 were
> excluded. Multiple lines with the same ISO value mean multiple images were
> used for calibration. Maybe these should be averaged?
I have consolidated the parameters. I also noticed that the standard fit
ranges in profile_image() are apparently meant to be used with daylight. I
took the profiling images with artificial lighting (bulb) since that seemed
the more realistic scenario (at least for high ISO) to me and it yields a
stronger red channel where I find chroma noise typically to be more disturbing
than in the blue channel. I had to adjust the fit ranges accordingly to get
more stable fits. The highest ISOs (10000, 12800) needed another slight
adjustment of the fit ranges.
Here is the improved presets.txt with multiple ISO lines joined (mostly picked
the best looking fit):
// olympus e-p5, no low ISO 100 or above 12800
// generated with artificial light to obtain a stronger red channel
// adjusted fit ranges to [0:0.55] / [0:0.8] / [0:0.3] accordingly
{"E-P5 iso 200", "OLYMPUS IMAGING CORP.", "E-P5", 200,
{4.44424187741465e-06, 2.99855385072016e-06, 1.08317199045895e-05},
{1.09677288263148e-08, 9.04107099379896e-09, 1.30291773934123e-08}},
{"E-P5 iso 250", "OLYMPUS IMAGING CORP.", "E-P5", 250,
{5.56404568178042e-06, 3.88782991026818e-06, 1.52908824923757e-05},
{1.27627405571592e-08, 1.06119420248892e-08, 1.27942248601444e-08}},
{"E-P5 iso 320", "OLYMPUS IMAGING CORP.", "E-P5", 320,
{6.78322923719586e-06, 4.75643030927288e-06, 1.85181122371483e-05},
{1.87557682468392e-08, 1.53786861708833e-08, 1.88038157506827e-08}},
{"E-P5 iso 400", "OLYMPUS IMAGING CORP.", "E-P5", 400,
{1.04253812695938e-05, 7.02374112282618e-06, 2.31162817450733e-05},
{9.25984889839442e-09, 7.79100363069323e-09, 1.10494506611547e-08}},
{"E-P5 iso 500", "OLYMPUS IMAGING CORP.", "E-P5", 500,
{1.26764254735444e-05, 8.77815265904943e-06, 3.24627782499901e-05},
{1.28713080714169e-08, 1.05051836289739e-08, 1.56390030553272e-08}},
{"E-P5 iso 640", "OLYMPUS IMAGING CORP.", "E-P5", 640,
{1.50679168050577e-05, 1.05737316413622e-05, 4.06051974483925e-05},
{1.88179942046864e-08, 1.54452060621139e-08, 2.16370443491548e-08}},
{"E-P5 iso 800", "OLYMPUS IMAGING CORP.", "E-P5", 800,
{1.85649982247609e-05, 1.28150239502753e-05, 5.08890579846725e-05},
{2.79079089036449e-08, 2.28431098551382e-08, 2.89754478125412e-08}},
{"E-P5 iso 1000", "OLYMPUS IMAGING CORP.", "E-P5", 1000,
{2.588685845435e-05, 1.73818666739912e-05, 6.39979523258199e-05},
{2.96740728193177e-08, 2.38036561743747e-08, 3.35456323419447e-08}},
{"E-P5 iso 1250", "OLYMPUS IMAGING CORP.", "E-P5", 1250,
{3.15717606338564e-05, 2.19365827330852e-05, 8.54927744902944e-05},
{4.0904651722172e-08, 3.14323709142334e-08, 4.25515306524108e-08}},
{"E-P5 iso 1600", "OLYMPUS IMAGING CORP.", "E-P5", 1600,
{3.81893590563908e-05, 2.65713214081756e-05, 9.79425216236713e-05},
{7.69151262328425e-08, 6.22034013445868e-08, 8.26285789994819e-08}},
{"E-P5 iso 2000", "OLYMPUS IMAGING CORP.", "E-P5", 2000,
{5.05306120757209e-05, 3.77049303988498e-05, 0.000136001257466992},
{9.36349966938621e-08, 7.1397612621607e-08, 1.07149354741741e-07}},
{"E-P5 iso 2500", "OLYMPUS IMAGING CORP.", "E-P5", 2500,
{6.10291318571623e-05, 4.05546149865647e-05, 0.000135298475680528},
{9.67001727379876e-08, 6.74763362268718e-08, 1.10272344388142e-07}},
{"E-P5 iso 3200", "OLYMPUS IMAGING CORP.", "E-P5", 3200,
{7.07150976715582e-05, 4.84280738873547e-05, 0.000157879395132559},
{1.14458973588607e-07, 7.10891425269051e-08, 1.26281774710791e-07}},
{"E-P5 iso 4000", "OLYMPUS IMAGING CORP.", "E-P5", 4000,
{0.000104621666701426, 6.10851569889013e-05, 0.000200520644053834},
{1.64926977693232e-07, 1.07097866815198e-07, 1.88935612885867e-07}},
{"E-P5 iso 5000", "OLYMPUS IMAGING CORP.", "E-P5", 5000,
{0.000155023418468101, 0.000127750815231256, 0.000289810885864649},
{2.64271269003561e-07, 1.69423371258086e-07, 2.94429977510558e-07}},
{"E-P5 iso 6400", "OLYMPUS IMAGING CORP.", "E-P5", 6400,
{0.000139542899549738, 9.63564051003203e-05, 0.000307751147062418},
{3.55545863858681e-07, 2.14196621792007e-07, 3.68309469223969e-07}},
{"E-P5 iso 8000", "OLYMPUS IMAGING CORP.", "E-P5", 8000,
{0.000244436488769286, 0.000130007112785455, 0.000387159500653682},
{4.60616790189685e-07, 2.65493005763617e-07, 4.78607186628961e-07}},
// the following two highest ISOs fitted with [0.1:0.5] / [0.1:0.6] / [0.0:0.3]
{"E-P5 iso 10000", "OLYMPUS IMAGING CORP.", "E-P5", 10000,
{0.000289365872315861, 0.000154285743005418, 0.000454407855408172},
{4.52846213810293e-06, 3.07664963070376e-06, 7.85852002087236e-07}},
{"E-P5 iso 12800", "OLYMPUS IMAGING CORP.", "E-P5", 12800,
{0.000358362598252066, 0.00018803731599601, 0.000469162340435641},
{4.61868441354983e-06, 3.80000488555163e-06, 1.14684667121615e-06}},
--
Christoph Scheurer GnuPG key Id: 0x6128C6B6
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