Yes, if you convert the dng files form your camera by the Adobe dng convertor, they are about 40 % smaller. That makes it easier and cheaper to store them. At least if the quality is still the same...

When I use my K10D and take photos in the dng format, their size is about 16 MB. When, on my computer, I upload these photos in the Adobe dng converter and 'convert' them to a new dng file, they are much smaller: 10 - 12 MB. That's nice as it saves space on my internal and external hard disk.
But can I trust this conversion? I have already noticed that after the conversion, the photos in the 'portrait' modus have to be rotated 90 degrees CCW to display them properly. So at least this information was lost.
So my question: can I totally trust the conversion by the Adobe dng convertor? Is it an 100 % lossless compression?

Thanks,

Myrdinn

I guess you're right: it's just a sales pep talk. Alas, it would have been nice if it were true...

I just bought the Pentax 50 mm lens. In the shop they told me that since Hoya has taken over Pentax completely, the prices went down and the quality even became better. Is there anyone who can confirm this?

I was thinking: because the sensor "saw" colours with a certain colour temperature. Maybe that could affect the quality of the final pic, if you have to make huge corrections of the white balance?
I don't know...

One of the advantages of taking pics in raw is that it gives the possibility to correct the white balance by using the raw convertor. But I wonder if these corrections create a (small) loss of quality, or not.
Even a raw file must contain some colour information. The colours of the objects we see differ depending of the colour temperature. A red flower in the evening sun looks different than a red flower under a cloudy sky. The colour temperature of the ligth affects the colours of what we see and photograph.
So, is there a limit in the corrections of the white balance we can make without losing some quality?

Thanks for the answers.
So the conclusions might be: we can convert from AdobeRGB to Lab Colour Spaceand back, but only once and only if necessary. The idea of doing it in a copy layer is always useful.

For some adaptations in Photoshop we have to change the modus from AdobeRGB tot Lab Colour Space. After the adaptations we have to switch back tot AdobeRGB. Does this have an influence on the quality of the picture?

Try here. I don't know if you find an answer here but it's worth looking:
http://www.pentax.co.jp/english/support/download_digital.html

Ok,

I 'm beginning to understand it. Thanks!

Myrdinn