spersky Posted November 24, 2009 Share #1 Posted November 24, 2009 Advertisement (gone after registration) I was reading lightroom tutorial and when you convert to DNG it said you could convert to to compressed DNG with no loss in image quality. Does anyone know if that is the same with the M9 when shooting in DNG. Should I use DNG or compressed DNG. Is there any change in image quality? Thanks Link to post Share on other sites More sharing options...
Advertisement Posted November 24, 2009 Posted November 24, 2009 Hi spersky, Take a look here DNG vs compresses DNG in M9. I'm sure you'll find what you were looking for!
jaapv Posted November 24, 2009 Share #2 Posted November 24, 2009 I know where this question came from I don't know about LR, I never use it, but any DMR user would not consider anything but an uncompressed file. A halfway decent computer can handle it effortlessly and disk space is cheap. Link to post Share on other sites More sharing options...
sandymc Posted November 24, 2009 Share #3 Posted November 24, 2009 There are two forms of compression that can be done to a DNG: 1. Level compression - this is what the M9 does in-camera. It is lossy - how much is lost, you need to decide for yourself. 2. Arithmetic lossless compression - that is what LR can do for you. As the name implies it is lossless, so you can use it without losing any image information. However be aware that a file that has been compressed in this way may no longer be readable by other non-Adobe software, e.g., C1. Sandy Link to post Share on other sites More sharing options...
spersky Posted November 24, 2009 Author Share #4 Posted November 24, 2009 Thanks for answering my question. That helps a lot. I will shoot with uncompressed DNG and use compressed DNG for lightroom. Link to post Share on other sites More sharing options...
chris_tribble Posted November 24, 2009 Share #5 Posted November 24, 2009 I use a similar approach - but be warned if ever you want to bring these into Aperture as this can't read LR DNG conversions apparently. THis doesn't worry me too much... Link to post Share on other sites More sharing options...
jaapv Posted November 24, 2009 Share #6 Posted November 24, 2009 Out of interest: what is there to gain with compressing the files, except some cheap disk-space? It makes them less future-proof. Link to post Share on other sites More sharing options...
spersky Posted November 24, 2009 Author Share #7 Posted November 24, 2009 Advertisement (gone after registration) Out of interest: what is there to gain with compressing the files, except some cheap disk-space? It makes them less future-proof. Nothing to gain except disk space. Good point. disk space is cheap. Link to post Share on other sites More sharing options...
James R Posted November 24, 2009 Share #8 Posted November 24, 2009 Out of interest: what is there to gain with compressing the files, except some cheap disk-space? It makes them less future-proof. Depends upon the camera and the person. A Nikon D3 compressed or not compressed RAW file is virtually the same. So, the question can also be stated why not compress? The question I have is can you tell the difference between a print made from a compressed vs non-compressed DNG created by an M9? Some one said it was "lossy," but that doesn't help much. Are we just pixel peeking and talking about "lossy" in terms that don't matter to the final print? Not sure what is gained, maybe some SDHC space. I'm just curious. Actually, I would suspect that the M9's write speed might take a hit. Link to post Share on other sites More sharing options...
spersky Posted November 24, 2009 Author Share #9 Posted November 24, 2009 Currently, all of my shots are taken with the DNG compressed. The shots are amazing. I do not pixel peep, but I want the highest "quality" I can get when I take a picture. So buying a few more SD cards is no big deal, and I can shoot in uncompressed. Thanks, Steve Link to post Share on other sites More sharing options...
James R Posted November 25, 2009 Share #10 Posted November 25, 2009 Currently, all of my shots are taken with the DNG compressed. The shots are amazing. I do not pixel peep, but I want the highest "quality" I can get when I take a picture. So buying a few more SD cards is no big deal, and I can shoot in uncompressed. Thanks, Steve Steve, Is the write time from camera to card longer when you are in the compress mode? Link to post Share on other sites More sharing options...
msadat Posted November 25, 2009 Share #11 Posted November 25, 2009 thats's cuz the dmr can not write compressed dng files I know where this question came from I don't know about LR, I never use it, but any DMR user would not consider anything but an uncompressed file. A halfway decent computer can handle it effortlessly and disk space is cheap. Link to post Share on other sites More sharing options...
250swb Posted November 25, 2009 Share #12 Posted November 25, 2009 Write speed is improved using compressed files. Shoot a seven frame burst and writing to a Extreme III 16gb card (timing it from end of shooting) it takes 20 seconds to write the seven uncompressed files, and 9 seconds to write compressed. That said, I'd only use compressed when the speed will be needed. Storage is very cheap and I haven't found any significant difference in processing time in CS4/ACR. Steve Link to post Share on other sites More sharing options...
scott kirkpatrick Posted November 25, 2009 Share #13 Posted November 25, 2009 The confusion comes from Leica's finally agreeing to allow the M9 to eliminate the lossy compression step that the M8 used to speed writing to disk -- take the square root of each pixel value before storing it and, presto, half as many bits to deal with. Canon's and Adobe's compression schemes are all supposed to be lossless, so that every bit of the original pixel values can be reconstructed when the file is decompressed for editing. Of course this take some computing power, not so hard to find in your PC but expensive onboard in the camera. I think Nikon's NEF files use a lossy compression scheme, but don't know for sure. After I finish editing a GB or so of M9 files, I use a good general purpose lossless compression scheme to compress them for storage (WinRAR in my case, but gzip and WinZip are almost as good). I get a reduction to about 5/8 of the original size, so the remaining 1/8 difference to the square root compressed files is indeed lost information. scott Link to post Share on other sites More sharing options...
chris_tribble Posted November 25, 2009 Share #14 Posted November 25, 2009 Out of interest: what is there to gain with compressing the files, except some cheap disk-space? It makes them less future-proof. Jaap - I have a number of reasons. write speed - even to top-end SD cards - uncompressed are slower. Also processing speed when working with large numbers of files on location (something I have to do a lot of and where the images are going to be given to clients as JPEGS). HIGH ISO - there's no advantage in using uncompressed. I've now defaulted to using uncompressed for 160 ISO (unless it's reportage) and compressed for everything else. Works for me - but on this one I reckon it's going to be different strokes for different folks ... Link to post Share on other sites More sharing options...
wlaidlaw Posted November 25, 2009 Share #15 Posted November 25, 2009 Out of interest: what is there to gain with compressing the files, except some cheap disk-space? It makes them less future-proof. There is an increase in handling speed as well. I notice, if I am running a slide show from my 2.53 gHz MacBook Pro in iPhoto or FotoMagico, where the images are M9 16 bit TIFF's, as I can't be bothered to keep two sets of images, a low res set for projection at 1080p and high res for printing, the wait for the image to change from the blurry thumbnail to the definitive image is quite long. As an experiment I compressed a few in LR to LR DNG and then ran a slide show from LR - it ran noticeably faster than either the TIFF's or the uncompressed DNG's. Wilson Link to post Share on other sites More sharing options...
jaapv Posted November 25, 2009 Share #16 Posted November 25, 2009 Yes, but for a slideshow on your screen 500Kb Jpgs will do the trick, and faster too. Link to post Share on other sites More sharing options...
wlaidlaw Posted November 25, 2009 Share #17 Posted November 25, 2009 Yes, but for a slideshow on your screen 500Kb Jpgs will do the trick, and faster too. Jaap, You need a bit better than this with a full HD (1920 x 1080) projector but 3MB JPEG's do just fine. However, as I said above, I cannot be bothered to do this, as I tend to make a slide show for the day by flagging various images and then making a smart folder. My next day's slide show may well be different. My images are all either 16 bit tiff's or for M9 ones, 16 bit uncompressed DNG's. I don't want to keep another set of images just for slides. I already have 16 bit tiff's of all the keepers and three archival sets on external HD's of all my DNG's, other than my first 6 months with the M8, which vanished in a lightning strike, when my iBook and attached HD went up in smoke. I also have a standard back ups of all my machines on yet more external HD's. After losing about 4 or 5 HD's over the years from various causes, I have got a bit paranoid about multiple back ups. Sadly I don't seem to be able to infect any of my family and it is difficult to get them to back up their computers at all. Wilson Link to post Share on other sites More sharing options...
bybrett Posted November 25, 2009 Share #18 Posted November 25, 2009 I'm shooting compressed , can anyone illustrate what I might be missing...? Link to post Share on other sites More sharing options...
chris_tribble Posted November 25, 2009 Share #19 Posted November 25, 2009 I'm shooting compressed , can anyone illustrate what I might be missing...? IMHO you're missing little if anything - especially above 200 ISO. So far as I understand it printers can't benefit from any difference, computer screens certainly can't, and I don't think the human eye's much good at telling the difference between compressed and uncompressed DNGs. Again - the discussion here was illumunating back in the early days (): http://www.l-camera-forum.com/leica-forum/leica-m9-forum/100936-m9-compressed-uncompressed-dng-whos-using.html#post1063557 http://www.l-camera-forum.com/leica-forum/leica-m9-forum/100936-m9-compressed-uncompressed-dng-whos-using.html#post1063557 Best... Link to post Share on other sites More sharing options...
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