sean_reid Posted October 18, 2006 Share #21 Posted October 18, 2006 Advertisement (gone after registration) Looking at the RAW files I have here from two different M8s, they are all exactly 10.1 MB. I wouldn't worry about this aspect, it's a red herring. Cheers, Sean Link to post Share on other sites More sharing options...
Advertisement Posted October 18, 2006 Posted October 18, 2006 Hi sean_reid, Take a look here M8-why 10MB-vs-DMR 20MB. I'm sure you'll find what you were looking for!
Guest guy_mancuso Posted October 18, 2006 Share #22 Posted October 18, 2006 Actually when firmware 1.3 comes out for the DMR . This is one way they can speed up the DMR by changing the DNG to more like the M8. This would increase read and write times and also make the buffer faster without doing a major overhaul to a existing system , not to mention extend battery life. I actually hope they do it Link to post Share on other sites More sharing options...
marknorton Posted October 18, 2006 Share #23 Posted October 18, 2006 Looking at the RAW files I have here from two different M8s, they are all exactly 10.1 MB. I wouldn't worry about this aspect, it's a red herring. Or should that read....? "Looking at the RAW files from two different M8s I have here, they are all exactly 10.1 MB. I wouldn't worry about this aspect, it's a red herring" Link to post Share on other sites More sharing options...
larry Posted October 18, 2006 Share #24 Posted October 18, 2006 Looking at the RAW files I have here from two different M8s, they are all exactly 10.1 MB. I wouldn't worry about this aspect, it's a red herring. Cheers, Sean Sean, Considering that's what Leica has stated in all of its literature, I'm sure you're correct. However, I'm going to hang on to those 20MB files -- who knows, maybe they'll become valuable Leica "collectibles." ;-) Larry Link to post Share on other sites More sharing options...
stevme Posted October 18, 2006 Share #25 Posted October 18, 2006 Perhaps your 20 mb files are files that contain BOTH the RAW image and the jpeg image. I believe there is an option somewhere to have the camera automatically record two versions of the same image. I know it works this way on my Canon. Steve Link to post Share on other sites More sharing options...
larry Posted October 18, 2006 Share #26 Posted October 18, 2006 Steve, The camera produces separate JPEG and RAW files. (I had it on the setting to produce both.) Larry Link to post Share on other sites More sharing options...
Jamie Roberts Posted October 18, 2006 Share #27 Posted October 18, 2006 Advertisement (gone after registration) Actually when firmware 1.3 comes out for the DMR . This is one way they can speed up the DMR by changing the DNG to more like the M8. This would increase read and write times and also make the buffer faster without doing a major overhaul to a existing system , not to mention extend battery life. I actually hope they do it Ok, I'm confused now... Guy--are you really saying you'd like Leica to use lossy compression and 8 bits per channel (instead of 16?) to speed up the DMR? I always thought this would make a difference, actually, to capture and to final manipulation. Even my Canons are all 12bits per channel in RAW. They are compressed, but losslessly compressed. I know I end up with an 8bit per channel image at the end of everything to print (even the RIPs I use throw away the extra data if you feed it more) but in editing, why do this with less color depth? In other words, won't this severely limit the initial quality of the RAW files? I know I see a huge difference in the way the DMR deals with extreme highlights compared to the 1ds2. The Canon has more headroom, but artifacts quite badly; the Leica has less detail, but manages extreme color shifts "like film"... Given the same RAW converter, I was assuming this was because the Leica captured more information to begin with. Am I missing something here? Why would Leica do this? I don't get it! Link to post Share on other sites More sharing options...
Guest guy_mancuso Posted October 18, 2006 Share #28 Posted October 18, 2006 Jamie i am not so sure they are working the DNG in 8 bit, I think there is something else going on here. I can't see how leica would go to a 8 bit file. I think we need someone from leica to explain what they are doing with the M8 file to make it smaller than the DMR file. i think there are some assumtions here that need to be proved. I may send a e-amil to my leica rep and see if we can get some technical data on why the M8 is 10mgs and why the Dmr is 20mgs and they are both 10 mpx camera's. It simply could be a way they have found a better raw compression method without degrading the image capture. not sure but this a great question being asked because it does sound funky. Link to post Share on other sites More sharing options...
sdai Posted October 18, 2006 Share #29 Posted October 18, 2006 Just my humble 2 cents on this topic ... this type of compression has never been lossless, and it shrinks the file size by extracting "redundant bits" in highlight and it's NOT like winzip as most folks would confuse ... Nikon initially said their compression was "virtually" lossless at the begining but then removed the "virtually" word from every literature they print. Nonetheless ... as Jamie has pointed out, it can't hide the defect from the compressed RAW files ... it's one of the major reasons why Nikon's NEF files are always prone to highlight blowout, and compressed NEF files are almost definitely having less latitude to process than the uncompressed files. Link to post Share on other sites More sharing options...
ho_co Posted October 18, 2006 Share #30 Posted October 18, 2006 Nikon initially said their compression was "virtually" lossless at the begining but then removed the "virtually" word from every literature they print. Nonetheless ... as Jamie has pointed out, it can't hide the defect from the compressed RAW files ... it's one of the major reasons why Nikon's NEF files are always prone to highlight blowout, and compressed NEF files are almost definitely having less latitude to process than the uncompressed files. Thanks for that info, Simon. You've cleared up a question for me. I haven't tried the compressed raw setting on my D200, but in its manual Nikon is still saying "virtually" lossless. Seems to me that brand is largely driven by marketing--such things as "3D Color Matrix Metering" for example. Why not just say, 'In this camera we have improved our already widely praised metering system yet again'? What the heck is a 3D Color or a Color Matrix anyway? (Snipe, snipe, snipe.) Why don't they spend more time on telling me before I buy whether a lens is going to be any good or not? That may be Leica's best advantage--it's never bad if it says "Leica." And that brings me back to the topic: This speculation is terrifying. The DMR performs as it does because it's 16-bit. (Is anybody else's RAW true 16-bit? I don't think so.) Leica would not back down to 8-bit quality on the M8. Andreas remarked that the ban is on posting RAW images, not on JPGs. Similarly, an acquaintance who visited Solms and got to shoot with the M8 was able to bring home his JPGs but no DNGs. Sounds to me as if M8 RAW may at the moment be only 8-bit; but cameras for delivery I'm sure will be 16-bit. (Of course I may be wrong ) --HC Link to post Share on other sites More sharing options...
sdai Posted October 18, 2006 Share #31 Posted October 18, 2006 Sounds to me as if M8 RAW may at the moment be only 8-bit; but cameras for delivery I'm sure will be 16-bit. (Of course I may be wrong ) Frankly, I've gone through the publicly available Leica M8 literatures (except the instructions) ONLY after reading this thread and curiously I can't find anything on the web with regards to the M8's color bit depth when capturing images ... not even Phil Askey's preview has anything about it. My best guess is, if they're doing 8-bit per channel "uncompressed" now, there must be some severe limitations in the hardware, namely the camera's DSP (just like the DIGIC chip people are familiar with in Canon's DSLRs) ... otherwise, I can think of any good explanation why they would do this even at alpha or beta stage. I kind of hope Mr. Kolev's findings was wrong ... I wouldn't mind a noisy sensor, just like many folks insist that the LX-2 is a great camera but, paying 5000 dollars for a camera only captures 8bit per channel (even it captures 14 bit or 16 bit per channel but downsampled to 8 bit channel) is plain stupid. Link to post Share on other sites More sharing options...
marknorton Posted October 18, 2006 Share #32 Posted October 18, 2006 I'm half-minded to send an email to Stefan Daniels and Otto Domes and ask them to look at this thread and make a statement here as to how it's being implemented. If we're going to end up with 8 bit data in the DNG, we may as well pack up now and go home. Link to post Share on other sites More sharing options...
larry Posted October 18, 2006 Share #33 Posted October 18, 2006 I'm pretty sure the bit depth for DNG is listed on the specifications page of the M8 brochure. There's a PDF available on Leica's Web site, but I can't download it here because of our firewall. Maybe someone could check this out? Larry Link to post Share on other sites More sharing options...
nemeng Posted October 18, 2006 Share #34 Posted October 18, 2006 I've done a bit of research about this. If you look at the Adobe DNG spec, downloadable from: http://www.adobe.com/products/dng/pdfs/dng_spec.pdf You'll notice DNG uses "lossless Huffman JPEG compression" to achieve the filesize saving. (p.15, "3. Restrictions and Extensions to Existing TIFF Tags" / "Compression") Although it sounds bad to use JPEG compression - doesn't it imply "lossy"? - if you look up "lossless Huffman" you'll see the compression is indeed truly loss-less and done without discarding any bits. See: 1. The Huffman compression algorithm 2. Image Compression: JPEG Huffman... So... don't worry about it. Huffman compression is merely an efficient way to save disc-space by mapping redundant bits to achieve approx 2:1 compression. Nothing is discarded and the image is not remapped or downgraded to 8-bit! It appears Leica were ultra-conservative with the DMR and switched off the DNG-compression option. With the M8, they got with the program and switched it back on. They pay a small cost in increased processing time, but with faster chips this is a moot point, and ultimately they save time by writing 50% less data to storage. :?) Link to post Share on other sites More sharing options...
sdai Posted October 18, 2006 Share #35 Posted October 18, 2006 But Andrew, the question is not about compression or not ... where does this 8-bit thing come from? was it just an incorrect tag in the DNG file or simply another Internet rumor? Link to post Share on other sites More sharing options...
Jamie Roberts Posted October 18, 2006 Share #36 Posted October 18, 2006 Simon... exactly right. I don't care if Leica uses truly lossless compression (TIFFs can be compressed, after all) but I *do* care if the DNG file is being produced at 8 bits per channel. As to this being a hardware problem, well, it certainly doesn't have to be! I tend to agree (or is that hope!?) that this might be the software / firmware limitation, and this is exactly why Leica doesn't want them passed around. Yes, I *hope* that's the case! This kind of bug is easy enough to create in software. I remember not too long ago when Canon's DPP software was outputting 8 bit TIFFs due to a bug. Let's hope an 8bit DNG was Leica's way of working quickly while they were optimising the image chain, and that they'll turn it back to the way it "should" be for production. Maybe that means the manual is incorrect on file size. That would OK with me Guy--if you know someone (and I know you do), well, now's the time to ask! Thanks in advance! Link to post Share on other sites More sharing options...
gravastar Posted October 18, 2006 Share #37 Posted October 18, 2006 What seems to be the clincher is that Mr Kolev says the non linear 16 to 8 bit transformation table is included in the RAW file. If his observations are correct, then Leica does need to address peoples concerns over this. Bob. Link to post Share on other sites More sharing options...
jrc Posted October 18, 2006 Share #38 Posted October 18, 2006 I'm not a technical guy, so I don't know what I'm talking about here, but under Technical Information on the Leica website for the M8, there's this: Data formats DNG (Digital Negative format not specific to any camera manufacturer), 2 different highly compressed JPEG levels. DNG file information 16 bit-color resolution, 10.2 Mbyte file size per picture Is that relevant to this discussion? JC Link to post Share on other sites More sharing options...
wparsonsgisnet Posted October 18, 2006 Share #39 Posted October 18, 2006 I'm half-minded to send an email to Stefan Daniels and Otto Domes and ask them to look at this thread and make a statement here as to how it's being implemented. If we're going to end up with 8 bit data in the DNG, we may as well pack up now and go home. Mark, I will gladly supply my half mind if it helps. In other words, please do ask the horse to speak about this confusion. I don't care what the process is as long as we aren't losing data. Regards, Link to post Share on other sites More sharing options...
johnll Posted October 18, 2006 Share #40 Posted October 18, 2006 Most of the better DSLRs have a RAW bit depth of 12, which is expanded to 16 for TIFs or Photoshop. A bit depth of 8 in RAW (DNG) files would be absurd, as it would have no real advantage over JPGs. It is quite impossible that Leica has done any such thing. For comparison, the RAW files from a Canon 5D (12.7MP) average a little over 10MB. There is some variation in RAW file sizes in this format resulting from the (lossless) compression, and I'd expect this to be the case with M8 DNG files also. 2^8 = 256 2^12 = 4096 (a huge increase) 2^16 = 65536 (the only reason this is worth doing is for processing - it costs no more for two whole bytes than it would for 1-1/2 bytes. Link to post Share on other sites More sharing options...
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