+ fujifilm_dynamic_range +
+ +đź”—Name
+fujifilm_dynamic_range.lua -
+đź”—Description
+Support for adjusting darktable exposure by Fujifilm raw exposure +bias. This corrects for a DR100/DR200/DR400 “dynamic range” setting.
+Based upon fujifilm_ratings by Ben Mendis
+The relevant tag is RawExposureBias (0x9650). This appears to +represent the shift in EV for the chosen DR setting (whether manual or +automatic). Note that even at 100DR (“standard”) there is an EV shift:
+100 DR -> -0.72 EV +200 DR -> -1.72 EV +400 DR -> -2.72 EV
+The ideal would be to use exiv2 to read this tag, as this is the same +code which darktable import uses. Unfortunately, exiv2 as of v0.27.3 +can’t read this tag. As it is encoded as a 4-byte ratio of two signed +shorts – a novel data type – it will require some attention to fix +this.
+There is an exiv2-readable DevelopmentDynamicRange tag which maps to +RawExposureBias as above. DevelopmentDynamicRange is only present +when tag DynamicRangeSetting (0x1402) is Manual/Raw (0x0001). When it +is Auto (0x0000), the equivalent data is tag AutoDynamicRange +(0x140b). But exiv2 currently can’t read that tag either.
+Hence for now this code uses exiftool to read RawExposureBias, as a +more general solution. As exiftool is approx. 10x slower than exiv2 +(Perl vs. C++), this may slow large imports.
+These tags have been checked on a Fujifilm X100S and X100V. Other +cameras may behave in other ways.
+đź”—Usage
+Start this script from script manager
+đź”—Additional Software Required
+exiftool (https://www.sno.phy.queensu.ca/~phil/exiftool/)
+đź”—Limitations
+đź”—Author
+Dan Torop dant@pnym.net
+