dkaye Posted July 13, 2015 Share #1 Posted July 13, 2015 Advertisement (gone after registration) I was surprised to see that the RAW/DNG files from the 24MP Leica Q run about 41MB in size. That's comparable to the 36MP Sony a7r and Nikon D800E, which I previously owned. I just don't need images with that many megapixels. I wondered what would happen if I used Lightroom CC to export the Leica Q DNG files as new DNG. Good news! If you export as an uncompressed DNG using compatibility with Camera RAW 5.4 or later, your DNG file sizes will be reduced by roughly 50%. Not sure why, but it's consistent. And I can't see any loss of quality. So then I tried exporting the DNGs to new DNGs using lossy compression, which is supported in Camera RAW 6.6 and later. The results: the 41MB RAW files shrink to roughly 5MB, depending on image complexity. That's only 12% of the original file size! I've studied the compressed DNGs at the 1:1 and even 2:1 view. I keep thinking I can see the difference, but when I use a blind test in which I don't know up front which is which, I'm wrong half the time. I'm sure some pixel gurus can see the difference in this amount of compression, but I can't. At least not reliably. My Lightroom import process now includes the added steps of exporting everything to new DNG copies and deleting the originals. Takes a while, of course. I'll be interested to hear what others think of the quality of the compressed DNGs. 2 Quote Link to post Share on other sites More sharing options...
Advertisement Posted July 13, 2015 Posted July 13, 2015 Hi dkaye, Take a look here Leica Q RAW/DNG File Size & Compression. I'm sure you'll find what you were looking for!
jaapv Posted July 13, 2015 Share #2 Posted July 13, 2015 I think deleting the originals is not a good idea, especially not if you are using lossy compression. You may not see a difference now, but you will see a difference if the time comes to process a file more extensively. Moreover, postprocessing software is progressing all the time - there will come a moment that you will regret throwing data away. There is no real reason to delete the originals either. Memory is cheap and getting cheaper all the time. A 4 terabyte disk will not break the bank and a second one for backup neither. Process compressed files by all means for speed and convenience, but don't throw your data away - you paid enough for the camera that produced them not to waste them. 1 Quote Link to post Share on other sites More sharing options...
mjh Posted July 13, 2015 Share #3 Posted July 13, 2015 (edited) I was surprised to see that the RAW/DNG files from the 24MP Leica Q run about 41MB in size. The Q doesn’t compress, neither losslessly nor lossy. 24 MP multiplied by 14 bits per pixel divided by 8 bits per byte yields 42 MB. Edited July 13, 2015 by mjh Quote Link to post Share on other sites More sharing options...
bernie.lcf Posted July 13, 2015 Share #4 Posted July 13, 2015 The Sony uses lossy compression in the A7 series, which is critisized quite frequently overe there with the orange folks I would keep the originals as storage is not the issue today: 3 Tb can be purchased at around €150 these days; at least I would keep the original file somewhere and maybe use higher compressed files in the libraray for daily use and until I need the OOC DNG file Quote Link to post Share on other sites More sharing options...
digitalfx Posted July 13, 2015 Share #5 Posted July 13, 2015 Converting a 41MB file to a 5MB file is going to result in degradation...I would suggest you avoid this unless quality is not important. Hopefully Leica will add a lossless compression option to upcoming FW similar to the M240 1 Quote Link to post Share on other sites More sharing options...
piran Posted July 13, 2015 Share #6 Posted July 13, 2015 There does seem to be some scope in the Leica Q DNG files for compression - not sure quite how lossless it might be manifested. If you wanted to save space have you considered the right click drive compression in a Windows box? It's lossless AFAIK and does the compress/expand in real time. It's a long time since I looked at compression logistics - given modern drive capacities. Quote Link to post Share on other sites More sharing options...
thighslapper Posted July 13, 2015 Share #7 Posted July 13, 2015 (edited) Advertisement (gone after registration) Not really sure why Leica has done this ....... Speculatively I assume that the beefed up Maestro 2 processing power and better electronics means that it can write to the card sufficiently fast that compression isn't required. File size and storage isn't really an issue these days as Jaap says ....... so there can't really be any other explanation ..... Edited July 13, 2015 by thighslapper Quote Link to post Share on other sites More sharing options...
Peter Pan Posted November 9, 2015 Share #8 Posted November 9, 2015 Converting a 41MB file to a 5MB file is going to result in degradation...I would suggest you avoid this unless quality is not important. Hopefully Leica will add a lossless compression option to upcoming FW similar to the M240 A firmware upgrade allowing for 12-bits DNG files would be good. I used 12 bits on my Nikon D800 reducing from 75mb to 35 mb, never saw any difference for my use. Quote Link to post Share on other sites More sharing options...
mjh Posted November 9, 2015 Share #9 Posted November 9, 2015 (edited) A firmware upgrade allowing for 12-bits DNG files would be good. I used 12 bits on my Nikon D800 reducing from 75mb to 35 mb, never saw any difference for my use. On its own, going from 14 to 12 bits would only achieve a fairly modest reduction in file size that wasn’t worth the effort. This is different if the reduction in bit depth is combined with (lossy or lossless) compression. But as a state-of-the-art lossless compression scheme would cut the file size in half (on average), reducing the number of bits would probably not be worth the effort even then (although it might increase the effectiveness of a lossless compression as it reduces hard to compress noise). Edited November 9, 2015 by mjh Quote Link to post Share on other sites More sharing options...
Peter Pan Posted November 9, 2015 Share #10 Posted November 9, 2015 On its own, going from 14 to 12 bits would only achieve a fairly modest reduction in file size that wasn’t worth the effort. This is different if the reduction in bit depth is combined with (lossy or lossless) compression. But as a state-of-the-art lossless compression scheme would cut the file size in half (on average), reducing the number of bits would probably not be worth the effort even then (although it might increase the effectiveness of a lossless compression as it reduces hard to compress noise). Is there a difference in DNG vs Nikon NEF files? When changing from 14 to 12 bits on Nikon D800 the file size was reduced from approx. 75mb to 35 mb Quote Link to post Share on other sites More sharing options...
mjh Posted November 9, 2015 Share #11 Posted November 9, 2015 Is there a difference in DNG vs Nikon NEF files? When changing from 14 to 12 bits on Nikon D800 the file size was reduced from approx. 75mb to 35 mb Of course there is a difference but the point is that 12 bits take up 14% less space than 14 bits – not enough to account for reduction in file size from 75 to 35 MB. There must be some compression at work (NEF supports both lossless and lossy compression although not all Nikon cameras offer both options) to explain the difference. Quote Link to post Share on other sites More sharing options...
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