PEF or DNG ?

OK shot two identical shots with K-5. ISO51200

DNG = 31.466Mb
PEF = 29.800Mb

After DNG conversion ....

DNG -> DNG = 20.399Mb
PEF -> DNG = 20.484Mb

Hmmmm. so not as much difference with high ISO stuff

It's worth looking at compressing PEF and DEF files. I've just tried a 23MB DNG off a GX-20 and it compressed to:

RAR 14.9MB
ZIP 17.6MB

RAR has a batch like facility to "Put each file in a separate archive" where it uses the filename and adds RAR to the end of each compressed file.

So gb_0236.dng gets compressed into gb_0236.rar
gb_0236.dng can then be deleted and space on the HDD saved.

RAR can also uncompress RAR and ZIP files to a Directory with the
same name as the file so gb_0236.RAR would uncompress into a Directory called gb_0236 if so required, keeping all the later edited files
together in one Directory.

Personally I would trust Pentax more than Adobe, so PEF over DNG is the preference for me.

With regards to file sizes, why waste effort with 2TB drives @ £60?

I'm surprised that anyone uses PEF now to be honest, DNG is less processing and more future proof - as unlocker mentions storage costs are now pretty insignificant so why not make life easy

Simon

? or ? or even ?

Glad that is only your preference. As for trusting Pentax over Adobe, could you expand that a little or should I wait for Pentaxoshop 1 or Pentacrobat 1?

Best regards

Pentax should know their file format better than Adobe. If they need, or want to change things to support anything new they might do, they can just do it and not wait for Adobe to change things several months later.

It's just a preference based on belief on one part and lack of belief on the other.

Less processing?

In what way?

G

Fair enough, I know normally there's no difference but the post by Smeggy etc about converting PEFs to DNG caught my eye - seems effort for no gain

Poking around inside a theoretically identical PEF and DNG off the K20D reveals that the DNG contains both a full size JPEG (4672x3104) and a
thumbnail JPEG (640x480) embedded in there in addition to the raw data. The thumbnail has black bars on it to adjust to the 2:3 aspect ratio. Meanwhile the PEF file has raw image data, a 640x480 JPEG and a 160x120 JPEG thumbnail. I'm guessing that your DNG->DNG conversion shrinks the files by losing the full-size JPEG image?

Cheers,
Paul

But does that JPEG exist before you view the file on the PC? If you have the Pentax Codec then it might add data to the file to enable it to have a thumbnail.

Just a theory...

Do you mean that Adobe will actually change their files because Pentax want something?

If read the rules of use off DNG there is a lot that Pentax can add to the file as long as the key things are in it that are needed to create the photo.

DNG is actually more a container then a file, the image information itself is based on the TIFF/EP standard, you can make DNG fully TIFF/EP compatible but you also have the options to embed the PEF file also in the DNG file for example.

ps. aren't most RAW files not based on TIFF so what is the real difference in quality?

If you look at the RAW photos on your camera you're actually looking at the JPG thumbnail.

I don't think a program on the PC adds data to your RAW file because it creates the photo from the raw data and not from the JPG file and if you save the edits you most of the time end up with a sidecar with DNG the side car is embedded so it might become slightly larger (few KB).

ps. if you change the image settings like contrast, saturation sharpness while you shoot in RAW those are actually applied to the JPG thumbnail. Not sure if you can change the size...

All makes sense.

Well, I would agree that there is little point in shooting PEF then converting to DNG, but does anybody do that?

For processing a RAW file, I would expect there to be little difference between PEF and DNG.

G

I've found no difference between PEF and DNG files IQ wise, even with the most microscopic pixel peeping