I am currently re-designing by photo-workflow and my plan so far is to convert the RAW-files from my Sony camera (which produces Sony's RAW, ARW) to DNG-format (which is Adobe's RAW). I use Adobe's "Digital Negative Converter" tool for that.
I am now testing my new workflow, using Darktable as the tool to generate the JPGs out from the RAWs. While testing, I found one distinction between the original RAW-files from my Sony and the DNG-files which surprised me a lot and keeps confusing me - I couldn't find a proper explanation for it.
--> It seems that all my pictures I generate from the converted DNG-files are slightly cropped. Just slightly, but visible. To test and verify that, I exported JPGs from the different RAW formats with darktable. I did not apply any modules to them (so not cropping, changing parameters etc, just exporting JPGs from the RAW data). The JPGs from DNG are slightly cropped.
From what I read, the original RAW-data should be untouched by the conversion tool. It's just the format of the file itself, storage of metadata etc which changes.
I am fully aware that the embedded preview-JPG is no benchmark for evaluating the content of the file. I did proper exports from RAW to JPG, and compared those, to evaluate this effect.
This question is not whether it is a good idea or not to convert to DNG. I want to do it because Sony does not offer lossless compression of their RAW files. I am aware of arguments against it (there were already a few questions/discussions here about that).