Originally posted by Photo Tramp There is no difference in the image by what you see the only difference is in the file size. But the PEF file would be considered a true RAW file.
I agree with your principal point. There IS no essential difference between the images produced by the two. However there is an important practical advantage to be gained by using the PEF.
PEF is a non-lossy compressed format whereas DNG as saved in the Pentax SLR (unlike the compressed format that DNG converter produces) is Non-compressed. My 4GB card will hold 239 DNG but approximately 350 PEF. Approximately because the degree of compression depende on the subject matter.
When DNG converter copies to my picture folder the compressed file is identical in size to the PEF. Obviously they use the same compression algorithm.
However, as regards the statement that DNG is not a RAW file: It is simply a data file as is PEF, NEF CR1 and so on. Therefore, it is reasonable to consider it a RAW file.
Do not let this distract you from the marvelous picture making ability of our Pentax system. Keep on SHOOTING! Forget about trucking...