In order to perform the lens correction, the pixels have to be de-mosaiced first. The resulting DNG file contains three components (R,G,B) instead of the single component in the raw data; in effect, the amount of image data becomes tripled; this format is mis-called "linear" in the DNG terminology.
Then my guess aboute the lens correction was right. Would be nice to have the option to switch off lens correction in this case, since as i understand the DNG only contains the demosaiced, lens corrected data and no longer the original RAW data.
Thanks for the clarification.
Can not you disable the lens correction feature in your camera?
I am not speaking for Adobe, but I "feel their pain": the Oly lens correction is only one feature of many-many among all native raw files. If the DNG interface contained options for all featires, which may be reasonable candidate for disabling, the dialog would become horrendeous.
The core of the problem is, that the previous DNG version [i]could not[/i] carry the lens correction info, for the specification did not have a respective element for that. Therefor the DNG converter has to perform the correction itself, instead of letting the "real" raw processing do that. This has been mended in the newer version, i.e. the DNG converter can now "pass" the lens correction info to the raw processor in meta format, the raw data itself does not need to be changed during the conversion in DNG.
I am also getting DNG files ranging from 3 to 6 times larger than the original ORF when using DNG Converter on images taken with my OLY M43 17/2.8 lens. The problem is documented (with sample files from both the OLY 17/2.8 and a ZN 28/2.8 on an adapter) in the folder: http://abdallah.hiof.no/photography/oly-ep2-test/. Not only do the files grow to significantly larger, but those from the OLY lens do not have thumbnails that are visible in the Mac OS Finder while those from adapter mounted lenses do.
Do we really have to live with this problem or is there hope that DNG Converter will produced a normal sized file after doing the correction specified by the embedded metadata? Could at least the embedded JPEG thumbnails be made visible?
- Børre Ludvigsen