DNG Compression

[robsonj]

Advertisement (gone after registration)

Does anyone else do this, or see any issue in doing it... After import to Lightroom Classic from the Leica DNGs, which are about 80mb each. Does anyone run the Lightroom convert to DNG command, with lossless compression enabled? This often reduces the size of the new DNG to 15-25mb.

Am I crazy to do this? I mainly discovered this on my Sony cameras which only offered lossy compressed RAWs, so I would shoot uncompressed RAW, then convert them to a lossless compressed DNG, so no information lost, just a savings of disk space.

[Gobert]

Since hard disk space is very cheap nowadays, I don’t care.

[robsonj]

4 minutes ago, Gobert said:

Since hard disk space is very cheap nowadays, I don’t care.

true, but it multiples right, my shots go to a smaller faster more expensive NVME drive, then get backed up to 2 locally attached spinning rust drives which then get mirrored to a nas drive which is also mirrors to Backblaze. so I think saving space is still relevant, plus it also allows me to keep more of my most recent work on the fastest NVME drive

Edited January 10, 2024 by robsonj

[M8X2]

I do this for every image under two stars per my rating system.

[marchyman]

23 hours ago, robsonj said:

Does anyone else do this, or see any issue in doing it... After import to Lightroom Classic from the Leica DNGs, which are about 80mb each. Does anyone run the Lightroom convert to DNG command, with lossless compression enabled? This often reduces the size of the new DNG to 15-25mb.

On my original Q I'd sometimes use save after making my metadata changes (keywords, rating, title, caption, etc) to update the DNG.  A side effect of doing that was shrinking the DNG from a typical 40+ MB to around 25 MB.  That's because the Q doesn't use any compression and LrC always uses lossless compression.   I've never tried that on an M11 file with are compressed out of camera.  I am curious.

M11 image picked at random: 64.5 MB.  After save -- no change. 

Now let me try the convert to to dng command.  On the same image I got a resulting file of 58.2 MB.   If that was a typical reduction it's not something I'd bother doing.  I'm now curious how you went from 80M to 15-25 MB.

[robsonj]

12 minutes ago, marchyman said:

On my original Q I'd sometimes use save after making my metadata changes (keywords, rating, title, caption, etc) to update the DNG.  A side effect of doing that was shrinking the DNG from a typical 40+ MB to around 25 MB.  That's because the Q doesn't use any compression and LrC always uses lossless compression.   I've never tried that on an M11 file with are compressed out of camera.  I am curious.

M11 image picked at random: 64.5 MB.  After save -- no change. 

Now let me try the convert to to dng command.  On the same image I got a resulting file of 58.2 MB.   If that was a typical reduction it's not something I'd bother doing.  I'm now curious how you went from 80M to 15-25 MB.

Are you also embedding the original raw file? I am not

[SrMi]

Advertisement (gone after registration)

23 hours ago, robsonj said:

Does anyone else do this, or see any issue in doing it... After import to Lightroom Classic from the Leica DNGs, which are about 80mb each. Does anyone run the Lightroom convert to DNG command, with lossless compression enabled? This often reduces the size of the new DNG to 15-25mb.

Am I crazy to do this? I mainly discovered this on my Sony cameras which only offered lossy compressed RAWs, so I would shoot uncompressed RAW, then convert them to a lossless compressed DNG, so no information lost, just a savings of disk space.

Original DNG: 72MB

Lossless compressed DNG: 68MB

Lossy compressed DNG is 14MB.

You are accidentally running with lossy compression.

[robsonj]

1 minute ago, SrMi said:

Original DNG: 72MB

Lossless compressed DNG: 68MB

Lossy compressed DNG is 14MB.

You are accidentally running with lossy compression.

O oooo, time to restore a couple of months of photos from the backup.  I did have that selected

[robsonj]

restored, will now recompress with lossy deselected, glad you commented on this!

[Photoworks]

On 1/10/2024 at 3:30 PM, robsonj said:

Am I crazy to do this?

yes

if you look at reviews you will find that in lossless compression you basically remote the jpg preview that is in there and some other optimization.
In some shots, there are real loss of data. I have not tried this myself, but a few people who do astrophotography saw a difference in their photos.

But if you don't care about this, go ahead. I just find it to be more work to process true DNG utility, manage the duplicates, backup, and than use Lightroom.

But probably I am not the right one to comment.
I copy all the images from the card, give the one I like a rating, and edit them not using Lightroom. I find deleting images a waste of time, and in 10 years those imperfect images may be interesting again.

 

[jaapv]

If you see a difference, it is not lossless So either Adobe is lying or these Internet pundits are not as expert as one might wish. Take your choice.