DNG File Size Import

[MSB]

:? I historically copy RAW files to a new location and add to the LR catalogue. The file sizes from my Canon 5'D were about 16MB for the native RAW files. I tried switching to convert to DNG and copy to a new location when importing. However, I noticed the DNG files were about 3'MB. Why are the DNG files almost twice the size as the native CR2 RAW files? I thought DNGs were supposed to be a little smaller.

 

[Brad Snyder]

I expect you've selected to 'Embed the Original Raw File' check box in the import preferences. This will add a full, untouched copy of the Original raw file to the DNG conversion, so that the raw file is basically in there twice.

 

[MSB]

Thanks Brad. I'll check on that.

 

[MSB]

Brad,
Checked the Import Setting in Preferences. They are set as follows:
File Extension: DNG
JPEG Preview: Medium
Image Conversion Method: Preserve RAW Image
Compressed: NOT Checked
Embed Original RAW File: NOT Checked

Are there any other setting that would affect the size of the DNG file?

 

[Brad Snyder]

Mark,

No, not to my knowledge. I truly wouldn't expect changes of that magnitude. There have been reports of huge file size increases on TIFFs being converted to DNG, but I haven't seen it before on DNG.

I'm shooting mostly 3'D CR2s, and I see about 1'% (very rough estimate) reduction in file size on DNG conversion.

Perhaps someone else will have an idea.

 

[MSB]

Thanks for the prompt reply.

 

[samdring]

Checking Compressed (lossless) gives me a 12 mb to 1' -ish reduction on 5D

 

[MSB]

Thanks Sam, but my understanding is that the uncompressed DNG should be slightly smaller than the native RAW file. I need to get to the bottom of this.

 

[Brad Snyder]

If you haven't already, perhaps give it a shot with the standalone DNG converter. That may help isolate the issue.

Find it here.

 

[MSB]

Brad,

The standalone DNG converter seems to be working fine. The converter DNG files are slightly smaller than the original RAW files. Where do I go from here?

 

[Brad Snyder]

Wow, I don't know. I don't think I've heard of this one before.

Maybe it's worth making a post at the Adobe U2U forums.

LR2 U2U Forum

[COLOR=#''''ff]DNG U2U Forum[/COLOR]


And of course there are the standard troubleshooting steps of defaulting the preferences, and reinstalling the s/w. Both of these are trivial. If not familiar, read this Troubleshooting LR