Thanks for the answer. I don't know for LR, I don't have it. I can understand that you try to match exposure between LR and DT for the situations where users want to import images and their treatment in DT, and not have to tweak the results too much to obtain what they had in LR. The problem I see with this method is very specific to the use I have of the xmp files (timelapse with the Ramperpro controller): those xmp files and the exposure correction they convey are used to smooth the exposure over the series of images. Indeed, since the cameras, when not in bulb mode, use 'discrete' exposure time (say, 1/100s, 1/80s but not 1/90s for example), those exposure corrections compensate for that and smooth the exposure all along the series. So, if the exposure compensation is modified, I suspect (but have not checked, yet) it's going to ruin the objective. I hope my explanations are not too confusing. Anyway, this is certainly a border case, and you should favor the majority of use cases: make the import from LR to DT consistent.
But if you don't mind, I'll give my feeling about the method. I'm surprised that the parameter which is tweaked to match LR and DT results is the exposure compensation. Indeed, exposure compensation is, at least to me, a parameter that can be physically explained and calculated (because totally correlated to physical and camera parameters such as ISO, time, aperture). And I would expect this parameter (and maybe only this one) to be consistent across the various softwares. There are so many parameters that can have an impact on the results**, that I wouldn't touch exposure compensation which is the only one with a 'physical' meaning. ** such as a very small tweak of the base curve. For all the cameras I have (Nikon D700, D810 and Panasonic LX100) I never use the default base curve for that matter. I hope you see my point. I don't mean to be negative. Thank you so much anyway! Denis Le 08/03/2016 22:38, Pascal Obry a écrit : > > Denis, > > > Following the topic we discussed one month ago (support of xmp files > > from the Ramperpro timelapse controller), and seeing that DT 2.0.2 > > now > > supports this functionality (thanks for the very quick integration!), > > I > > gave a try with some files (one sample below, NEF and xmp). The > > exposure > > correction I see in DT after import does not match the value in the > > xmp > > file (in the example below, exposure correction is 0.29048 in the xmp > > file, but I read 0.26eV in DT). > > Right indeed. The exposure compensation done in Lr and dt does not > match. All changes in Lr and dt btw, not just exposure. This means that > what I have done is to "match" the values by looking at the results > from both software. This is not perfect and will never be. > > Are you saying that using the same value on Lr and dt give the same > result to you? Try with -1, -.5, +.5 and +1 EV in both softwares and > compare the output, is that really the same? > > It was not for me (Lr 3.x at the time) but I cannot check now as I have > moved away from Lr since a long time. > > Cheers, > > ____________________________________________________________________________ darktable user mailing list to unsubscribe send a mail to darktable-user+unsubscr...@lists.darktable.org
