chris_tribble Posted October 3, 2009 Share #1 Posted October 3, 2009 Advertisement (gone after registration) I'm interested in the varying experiences of current users of the M9 in this area as it has a potentially major impact on the kinds of resources we'll need for image processing and storage. One reason for asking the question is that when I first got the M9 I started using uncompressed DNGs and found them unwieldy across the computers I use - older Dual Xeon 4GB machine at one base, fast Dell Precision Workstation (4GB RAM) at another, and a perfectly OK Toshiba laptop with 3GB RAM is use for editing when on the road - all running XP Pro... I know that Windows 7 64 bit is better - but having just shelled out for the M9 (and considering getting a second body) I DON'T want to have to replace all my PC stuff too! Another reason is to get a sense of how critical the in-camera 14 bit image really is... My feeling is that unless I'm working with High ISO and / or really critical landscape or product photography the IQ I get from the downsized DNGs is great - i.e. I can now get beautiful A2 prints from my M9 files. A3+ was the limit for the M8.... I'm aware that Jono Slack's tended to default to compressed DNG - very interested in hearing real world experience from M9 users on what they're doing - and why ... Quote Link to post Share on other sites More sharing options...
Advertisement Posted October 3, 2009 Posted October 3, 2009 Hi chris_tribble, Take a look here M9 - compressed / uncompressed DNG - who's using what?. I'm sure you'll find what you were looking for!
fishblimp Posted October 3, 2009 Share #2 Posted October 3, 2009 This question is a great one. I'm unfamiliar with the difference. I assume "compressed" means that the file undergoes some sort of loss of data, but is it lossless compression? What would be some detectable details in a copmressed DNG vs. an uncompressed DNG? Is there less color range? Quote Link to post Share on other sites More sharing options...
bybrett Posted October 3, 2009 Share #3 Posted October 3, 2009 Compressed: for grace, space and pace... 30x20's are unreal. Quote Link to post Share on other sites More sharing options...
michali Posted October 3, 2009 Share #4 Posted October 3, 2009 I'm working off my MAC Book 2.4Ghz & 4GB RAM, shooting uncompressed, no issues at all with processing speed of the M9 files. Haven't tried shooting uncompressed DNG yet. I'm using 4GB SCANDISK cards on the M9 also trying out an 8GB card. Storing the files in 3 places; the keepers on the computer and also everything on 2 external hard drives. Quote Link to post Share on other sites More sharing options...
melissah Posted October 3, 2009 Share #5 Posted October 3, 2009 Maybe this will help. Note! This is from one w/M8 with no M9 in the the future. That being said. The computer, lightroom, and Photoshop is your darkroom If you have oodles of time and/or not much money then ofcourse continue with an older slower system. But for me post is imtp. And so is catalogue (lesson I'm learning the hard slow way via lightroom) because i'd never properly keyworded anything... I use macs. Why? Because my mac (allbeit w tons of ram) is native to adobe, and my RIPsoftware and my screen. Now that I've digressed mostly my point is this. Ur computer is ur darkroom. Put I to it what u would like to see come out. Best Melissa Quote Link to post Share on other sites More sharing options...
vanhulsenbeek Posted October 3, 2009 Share #6 Posted October 3, 2009 I'm working off my MAC Book 2.4Ghz & 4GB RAM, shooting uncompressed, no issues at all with processing speed of the M9 files. Haven't tried shooting uncompressed DNG yet. . You mean: compressed? Quote Link to post Share on other sites More sharing options...
chris_tribble Posted October 4, 2009 Author Share #7 Posted October 4, 2009 Advertisement (gone after registration) Hi - while I agree with all the stuff about the computer being your darkroom etc, this isn't really the issue. I've been using LR since it came out, have stacks of hard drives + DVD archives held in different physical locations and am contemplating a subscription to Imageshelter... The real issue here is IQ and whether or not there are compelling reasons for shooting uncompressed DNG. Brett's comment "Compressed: for grace, space and pace... 30x20's are unreal" is poetic but not necessarily informative. In an earlier exchange - right at the beginning of the M9 journey there was a discussion which led me to think that uncompressed was the way to go: http://www.l-camera-forum.com/leica-forum/leica-m9-forum/98212-lightoom-mangling-m9-images-there-compression-2.html#post1039231 - in real world use, however, I'm not sure that this is necessarily the case. Experience based comments welcome - Jamie, if you're out there, Jaap. what DNG format are you using? Quote Link to post Share on other sites More sharing options...
erl Posted October 4, 2009 Share #8 Posted October 4, 2009 Chris, currently I am going through the same mental gyrations as you on this and related issues. So far, I have only shot compressed, mostly on extreme or difficult stuff, both work and personal. In the next 24hrs maybe, I will produce some large prints (A2) but I have every confidence they will be better than fine. I am also on the verge of a trip for which I will need more SD cards. My dilemma is "what size". I have been in the habit of limiting myself to 4GB cards with the M8, but I know that will need to drastically increase with the M9. I'm thinking 8 or 16GB. I filled a 4GB card in an hour at a childs party this afternoon. The same the day before on a job. These cameras are space hungry. More HD's for the computer coming up! I am not sure what real benefits the uncompressed DNG's offer in terms of DR and low light shooting. I will experiment in the coming week as their is no work to test it. Quote Link to post Share on other sites More sharing options...
reven Posted October 4, 2009 Share #9 Posted October 4, 2009 Well I think first we have to know what the actual difference is. Is the compressed DNG like the m8, with only 8 bits ? If so I would never shoot it. Why in hell would I throw away useful information. Or is the compressed DNG lossless ? On the other hand I probably would never shoot something compressed if there is a quality loss. I really think if one buys a camera for 6k and lenses from 1k upwards you should have the money for a few SD cards and enough drive space at home. I believe that you can make great 20x30 prints from the m9. Perhaps even larger. So the only question is, do we lose quality through using compressed DNGs. As far as i have read and heard yes, there is some drawback in DR. Quote Link to post Share on other sites More sharing options...
erl Posted October 4, 2009 Share #10 Posted October 4, 2009 Well I think first we have to know what the actual difference is. Is the compressed DNG like the m8, with only 8 bits ? If so I would never shoot it. Why in hell would I throw away useful information. Or is the compressed DNG lossless ? On the other hand I probably would never shoot something compressed if there is a quality loss. I really think if one buys a camera for 6k and lenses from 1k upwards you should have the money for a few SD cards and enough drive space at home. I believe that you can make great 20x30 prints from the m9. Perhaps even larger. So the only question is, do we lose quality through using compressed DNGs. As far as i have read and heard yes, there is some drawback in DR. Agreed Reven. The question not about 'affording' the cards and HD's, but rather what size to choose as optimal when upgrading. This will partly be governed by any decision to shoot compressed and/or uncompressed. Each of us will mostly likely have different 'trigger' points for switching from one to the other. Sharing our observations and experiences accelerates the learning and understanding. Regarding the 'drawback in DR' for compressed, that you refer to. Would it not be fair to put it the other way round? ie. An increase in DR if using uncompressed? Or am I misreading what you meant? Quote Link to post Share on other sites More sharing options...
luigi bertolotti Posted October 4, 2009 Share #11 Posted October 4, 2009 I seem to remember, from other threads, that it has been clarified that M9 DNG compressed uses the same 14 to 8-bit conversion through lookup table / curve, as into M8, so giving the same DR (with more pixels, of course). What me too haven't yet understood completely is in which conditions (print dimensions and tonal range of the scene) the 14 bit uncompressed gives a real visual advantage. About DR/tonal range, I would appreciate if some M9 user would post some comparision shot... as for print, of course, only "spoken" examples can be reported hereby. Quote Link to post Share on other sites More sharing options...
stunsworth Posted October 4, 2009 Share #12 Posted October 4, 2009 ...do we lose quality through using compressed DNGs. As far as i have read and heard yes, there is some drawback in DR. I didn't think there was any loss of dynamic range. Rather the potential loss was in graduations in highlights since fewer bits are assigned to them. Whether this 'loss' is visible is another matter and since I don't have an M9 I don't know Quote Link to post Share on other sites More sharing options...
sandymc Posted October 4, 2009 Share #13 Posted October 4, 2009 I seem to remember, from other threads, that it has been clarified that M9 DNG compressed uses the same 14 to 8-bit conversion through lookup table / curve, as into M8, so giving the same DR (with more pixels, of course). The compression scheme uses the same curve, but because of the way black levels are implemented in the M9, you lose some of the 256 levels to 8-bits gives you, the number depending on ISO setting. At ISO 160 you lose 14 of the 256 levels, at ISO 2500 50 of the 256 levels. Will you ever notice? - Well, the major loss is at high ISO, where the image quality isn't too great anyway, so I suspect that unless you are doing some really aggressive post processing such as a lot of shadow recovery, probably you won't notice. But I think that the compression scheme could have been better implemented by just making it entirely identical to the M8's, rather than having the non-zero black levels. Sandy Quote Link to post Share on other sites More sharing options...
reven Posted October 4, 2009 Share #14 Posted October 4, 2009 If that is true I would never want to shoot compressed. 256-14 are 242, this is horrible, especially if you work with smooth small tonal transitions. After some small post work you would see large differences. Quote Link to post Share on other sites More sharing options...
chris_tribble Posted October 4, 2009 Author Share #15 Posted October 4, 2009 (edited) Hmmm - I give below a quickly done set of shots at a space across from where I'm sitting. All taken at 400 ISO 1/60th second f2.8 using a monopod as stabiliser. NO sharpening applied. First set are DNG compressed / Second set DNG uncompressed. I'm fairly sure that in prints I'd not notice a difference. Interesting to see if others are up for doing some parallel tests... I've copied the original DNG's to: http://dl.getdropbox.com/u/862415/Leica_M9/L1001098.DNG http://dl.getdropbox.com/u/862415/Leica_M9/L1001101.DNG NB - you have to register with DropBox to access the files... also - the DNGs are currently uploading (11.43 London time) and won't be available for a little while... Welcome, dear visitor! As registered member you'd see an image here… Simply register for free here – We are always happy to welcome new members! Edited October 4, 2009 by chris_tribble 1 Quote Link to post Share on other sites Simply register for free here – We are always happy to welcome new members! ' data-webShareUrl='https://www.l-camera-forum.com/topic/98921-m9-compressed-uncompressed-dng-whos-using-what/?do=findComment&comment=1061051'>More sharing options...
Overgaard Posted October 4, 2009 Share #16 Posted October 4, 2009 (edited) Without being an expert, JPG can only be stored in 8-bit JPG why comparing JPG files will not show any difference. I've never really been able to notice a (big enough) difference on screen when changing a scanning from 16 to 8 bit. I wonder if any Apple screens can actually show other than 8 bit. Eizo mention 12 and 16 bit for their top range screens - but as 12 bit/16 bit hardware color correction so one would expect you can also see 16 bit files. But "traditionally" 16 bit is for print files, for obvious reasons they're of no use for online web use (as JPG doesn't support more than 8 bit). I shoot uncompressed DNG because I want the biggest and most defined files for the future. If we look around at television and music industry, the highest possible resolution possible would be the only choice for any media used in the future. My workflow is sRGB 8bit for the compatibility and speed of today, but I like to keep the original files in storage for later re-edits in Adobe RGB, 16 bit and whatever may come. Also, though I haven't tested the actual speed difference, I would expect uncompressed DNG files to require no processing/scaling in camera (but more writing time to the card) whereas I would expect compressed DNGs to require processing/scaling power in camera. Why logically, uncompressed should be less work for the M9 to process. I use 16GB card in the M9. The price of the Sandisk Extreme III 16GB card today is the same as the 512 MB card was 7 years ago. So that gives a hint that one should not save on file sizes for storage reasons. Hard drives will continue to expand so todays 2TB drives will be 64TB in less than 10 years. Plenty of space for uncompressed files ;-) Edited October 4, 2009 by overgaardcom Quote Link to post Share on other sites More sharing options...
michali Posted October 4, 2009 Share #17 Posted October 4, 2009 You mean: compressed? Thank you for correcting me, it should read: "Haven't tried shooting compressed DNG yet" Quote Link to post Share on other sites More sharing options...
michali Posted October 4, 2009 Share #18 Posted October 4, 2009 Chris- thanks for doing the comparative shots, however it is very difficult to pick up any significant differences, I suppose we're limited by the computer's screen resolution. I fully agree with Thorsten's point, which IMO, concisely sums it all up: "I shoot uncompressed DNG because I want the biggest and most defined files for the future. If we look around at television and music industry, the highest possible resolution possible would be the only choice for any media used in the future. My workflow is sRGB 8bit for the compatibility and speed of today, but I like to keep the original files in storage for later re-edits in Adobe RGB, 16 bit and whatever may come. " Quote Link to post Share on other sites More sharing options...
chris_tribble Posted October 4, 2009 Author Share #19 Posted October 4, 2009 Chris- thanks for doing the comparative shots, however it is very difficult to pick up any significant differences, I suppose we're limited by the computer's screen resolution. [/i] Michali - I agree re the problems of on-screen viewing - do download the DNGs and have a look though - again, I'm not sure how significant the benefit is in normal shooting conditions... Quote Link to post Share on other sites More sharing options...
lars_bergquist Posted October 4, 2009 Share #20 Posted October 4, 2009 The FDA would not approve even a deodorant on the basis of the opinions and 'facts' we have seen here. The only chance of resolving the question would be a proper double-blind test, the way it is done with new medical drugs. Here is how: 1. A number of subjects are shot identically (same camera and placement, same lens, same lighting, same everything) and each pair of exposures are stored uncompressed, and compressed. 2. The exposures are printed identically (ideally, no PP) and the prints are coded. A protocol shows which print is what, but it is kept secret. 3. The prints are handed to a test administrer, wo shows them to the test subjects, asking them which prints they think are compressed, and uncompressed. Note that the administrer is just as 'naive' as the test subjects, so he cannot unintentionally bias either the subjects or his own protocol. 4. The answers are checked against the secret protocol. Standard statistical methods are used to determine if the answers are really different from just random chance, and in that case, by how much. 5. The whole thing is written up in a paper, with complete procedures, and published so that other workers can repeat the experiment. This is called 'peer review' and is mandatory in the scientific world. This, as you can see, is somewhat different from "nine out of ten pro photographers say that uncompressed DNG puts stars into your hair". I am waiting. The dour old man from the Age of Evidence Quote Link to post Share on other sites More sharing options...
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