Originally posted by UncleVanya Both PEF and DNG are true raw formats - they contain the sensor data but formatted in two different ways. The camera can save either format without conversion. As far as I can tell there is no advantage to PEF.
Originally posted by Adam TLDR: there's basically no difference, except fewer programs can open PEFs. Thus we tend to prefer the DNG format
What they said. The two formats are essentially equivalent and there is no real advantage in regards to software support. Both are strictly proprietary with the main difference that the DNG specifications have been published. There is some potential that DNG may become a standard of sorts, except that adoption (camera support), cross-compatibility, and quality of implementations (outside of Adobe products) is mixed.*
Is DNG future proof? Only if the assumption is that Adobe will have significant historical or industry prominence 100 years from now or even ten years from now. (Anyone remember Kodak's KDC?) At present, TIFF would appear to be the safer choice for archived files and has the advantage of preserving the post-processing intent of the artist without needing than a compliant TIFF image reader.**
Steve
* This is difficult to explain except to say that Adobe generated DNG (e.g. Lightroom export) may or may not be readable with non-Adobe product. Similarly Pentax-generated DNG may not be readable or fully supported by software capable of reading Adobe-generated DNG.
** There is little to be gained from archiving a RAW file by itself if the artist had specific intent for image processing. A RAW file is strictly analogous to a film negative. For example, the negative for Ansel Adams "Moonrise, Hernandez, New Mexico" still exists, but even a master printer would have difficulty reproducing a print without Adams notes and maybe even with it.
Adobe DNG may contain processing instructions (e.g. generated on export of developed image from Lightroom or or by metadata save), but those are only validly interpreted by the original or compatible software.