Currently Being ModeratedAug 4, 2013 8:57 AM (in response to Marc.Scholl@uni-konstanz.de)
I think you've just about answered your own question. Go back to PEF!
I'm using Sony cameras now but shot with Pentax for several years. During that time I too experimented with in-camera DNG. At first, it seemed like a great idea — one universal format that future-proofed my raw files. Well, it didn't turn out that way. For one thing, the big camera makers (Canon, Nikon, Sony) don't support DNG: they use their own proprietary formats and will continue to do so for the forseeable future. But the less common formats (like PEF) are still supported by all raw converters like Aperture and Lightroom. DNG files caused me way more problems than PEF ever did. Some of the programs I worked with at that time (Bibble Pro comes to mind) didn't even support DNG, for reasons that they defended on their website. And I too had the experience you've had, of DNG files being rendered a bit differently. I thought that wasn't supposed to happen but it did.
Now I save my Sony .ARW files. I have no intention of converting them to DNG in the future. My sense is that, with no major camera manufacturer supporting DNG, it's really got no future.