DNG in-camera vs DNG from Lightroom?

rfortson · 10-28-2008, 08:22 PM

Does anyone know the difference between the DNG format directly from my camera, and a DNG created in Lightroom from a PEF? Kelby recommends converting your raw files to DNG upon import to the computer and one of the reasons he uses is the DNG is smaller than the original raw file. I know the DNGs created in-camera are larger than the PEFs, so I was wondering if that's always the case, or just the case with the in-camera files.

mithrandir · 10-28-2008, 08:55 PM

In the case of the K10D, the PEF RAW files are created with lossless compression. The DNG RAW files are not compressed and are larger. If you import PEF RAW files into DNG in lightroom, the files get a second dose of lossless compression and are even smaller.

rfortson · 10-29-2008, 07:37 AM

Originally Posted by mithrandir

In the case of the K10D, the PEF RAW files are created with lossless compression. The DNG RAW files are not compressed and are larger. If you import PEF RAW files into DNG in lightroom, the files get a second dose of lossless compression and are even smaller.

Makes sense. Thanks for the clarification. I may start converting all my PEFs to DNG upon import.

Wulifou · 10-29-2008, 08:49 AM

Originally Posted by rfortson

Kelby recommends converting your raw files to DNG upon import to the computer and one of the reasons he uses is the DNG is smaller than the original raw file.

since I haven't read his book, what are the other reasons to convert to DNG? (other than beeing an Adobe product .....)

rfortson · 10-29-2008, 04:05 PM

Originally Posted by Wulifou

since I haven't read his book, what are the other reasons to convert to DNG? (other than beeing an Adobe product .....)

Size/space was by far the overriding factor, but he also talked about the DNG containing all the metadata (including adjustments) inside the file, while the raw file needed an XMP sidecar file. Finally, I think he mentioned the open format for DNG.

So far, it's a very helpful book. I read "The Digital Photography Book" by him (and liked it) and this is written in much the same conversational style. However, this is a linear book. He says it's intended to be read in order from front to back, rather than jump around. Makes sense, since it follows a typical workflow approach. However, you can still pick it up and figure out whatever he's talking about.

walter · 10-29-2008, 06:32 PM

Originally Posted by Wulifou

since I haven't read his book, what are the other reasons to convert to DNG? (other than beeing an Adobe product .....)

I think DNG is probably more likely to be supported in future versions of software, especially if you use Adobe software. There's always a chance that new software will not be able to open files from an old camera.

*LaRee* · 10-30-2008, 11:15 PM

Originally Posted by rfortson

Size/space was by far the overriding factor, but he also talked about the DNG containing all the metadata (including adjustments) inside the file, while the raw file needed an XMP sidecar file. Finally, I think he mentioned the open format for DNG.

So far, it's a very helpful book. I read "The Digital Photography Book" by him (and liked it) and this is written in much the same conversational style. However, this is a linear book. He says it's intended to be read in order from front to back, rather than jump around. Makes sense, since it follows a typical workflow approach. However, you can still pick it up and figure out whatever he's talking about.

The big thing for me is having all the metadata and lightroom adjustments inside one file instead of having the XMP sidecar file. No worry about them getting separated if they are one file.
I've been shooting DNG, maybe I'll try a shoot with PEF and convert on import to lightroom to save some card space when shooting. hmmmm...

JonPB · 10-31-2008, 05:28 AM

For what it's worth, you can compress a camera DNG in Lightroom by using "Update DNG Preview & Metadata" from the Metadata menu or the contextual menu. This is a standard part of my workflow, as it reduces the file from 16MB to 7-11MB. I'd be curious to know whether a PEF -> LR DNG is smaller than a camera DNG -> LR DNG; my GX-10 doesn't produce PEFs.

Wulifou · 10-31-2008, 07:09 AM

Originally Posted by LaRee

The big thing for me is having all the metadata and lightroom adjustments inside one file instead of having the XMP sidecar file. No worry about them getting separated if they are one file.
I've been shooting DNG, maybe I'll try a shoot with PEF and convert on import to lightroom to save some card space when shooting. hmmmm...

Good point. I didn't realize the sidecar file aspect until now. I think I remember a post where the discussion DNG vs. PEF was related to color aspects(maybe due to some kind of compression ?). Does someone has any kind of experience with that ?

rfortson · 11-02-2008, 11:06 PM

Okay, I shot a couple of test shots today. First was PEF and it was 15.8 mb. The second was in-camera DNG and it was 23.4 mb. I then had both files converted in Lightroom 2.1 to a DNG and they both ended up smaller. The PEF finished up at 13.6 mb and the in-camera DNG wound up at 13.9 mb.

So, I've decided that I'll shoot in PEF and then convert to DNG when I import them. That way I'll save space on my cards while shooting, and then save space on my HD for storage.