freecitizen Posted September 13, 2013 Share #1 Posted September 13, 2013 Advertisement (gone after registration) On page 164, the M240 manual states : " The available compression for DNG format .... retains all of the post-editing performed on the image data ..... " I don't understand this ............ I thought RAW meant direct recording of the sensor readout without alteration. Does the M 240 process/edit the DNG files in some way before writing to the card ? Does anyone know what is done in-camera to the DNG files ? Hoping someone can enlighten me please .... Many Thanks. Quote Link to post Share on other sites More sharing options...
Advertisement Posted September 13, 2013 Posted September 13, 2013 Hi freecitizen, Take a look here M 240 compressed/uncompressed and in-camera processing. I'm sure you'll find what you were looking for!
jaapv Posted September 13, 2013 Share #2 Posted September 13, 2013 All cameras will perform some firmware manipulations to the sensor readout before writing the data to the raw file. Quote Link to post Share on other sites More sharing options...
01af Posted September 13, 2013 Share #3 Posted September 13, 2013 I think they mean to say, both compressed and uncompressed DNG formats provide the full range of image data for your subsequent post-processing. In this case, it's not just a dorky "English For Runaways" translation—in the German-language manual, this particular paragraph's wording also is just nonsense, and the English manual actually is an accurate translation thereof. Quote Link to post Share on other sites More sharing options...
Thomas Chen Posted September 13, 2013 Share #4 Posted September 13, 2013 Does anyone know what is done in-camera to the DNG files ? Hoping someone can enlighten me please .... Many Thanks. The article titled "Leica M Colour" by Mr. Michael J. Hussmann in the "Leica Fotografie international" or LFI magazine 5/2013 will answer your question, especially the section "Profile" from page 64 to the end. However, read it over from the beginning is desirable. For the fundamental knowledge about the relationships among RAW, JPEG and DNG, please refer to the Chapter 1 and 2 of the book "Camera Raw with Adobe Photoshop CS5" by Jeff Schewe and Bruce Frase, published by Peachpit Press. Berkerly CA. ISBN-13: 978-0-321-71309-4. Regards, Thomas Chen Quote Link to post Share on other sites More sharing options...
jaapv Posted September 13, 2013 Share #5 Posted September 13, 2013 I think they mean to say, both compressed and uncompressed DNG formats provide the full range of image data for your subsequent post-processing. In this case, it's not just a dorky "English For Runaways" translation—in the German-language manual, this particular paragraph's wording also is just nonsense, and the English manual actually is an accurate translation thereof. The problem with manuals in general is that they are usually not written by the manufacturers themselves but by manual-writing firms. Not everybody in those firms is 100% up to speed with the technical details of the products they are writing for, let alone the more in-depth theoretical background. Actually in general I find Leica's manuals rather good compared with the gobbledegook that most Japanese manufacturers produce. Quote Link to post Share on other sites More sharing options...
freecitizen Posted September 13, 2013 Author Share #6 Posted September 13, 2013 It has occurred to me that the corrections applied for each individual lens, as identified by the 6 bit coding, might be a modification done in-camera and the resultant modified DNG file then saved to card. Perhaps this is what the manual meant ................ 1 Quote Link to post Share on other sites More sharing options...
hoppyman Posted September 13, 2013 Share #7 Posted September 13, 2013 Advertisement (gone after registration) On page 164, the M240 manual states : Notes: The standardized DNG (Digital Negative) format is used for storage of completely unprocessed raw picture data. The available compression for DNG format – is loss-free, i.e. it does not cause any deterioration in quality – retains all of the post-editing performed on the image data – allows faster saving – takes up less memory space. I don't understand this ............ I thought RAW meant direct recording of the sensor readout without alteration. Does the M 240 process/edit the DNG files in some way before writing to the card ? Does anyone know what is done in-camera to the DNG files ? Hoping someone can enlighten me please .... Many Thanks. There is always some processing applied to raw files in camera. In the case of digital M cameras that includes vignette correction and for "red edge" effects due to characteristics inherent in the M system with sensors. Different camera systems make more or less use of corrections at this point in the image chain. For example some other systems (not the Leica M's) apply significant distortion corrections at that point as a system design choice. "Unprocessed "in the first note means that colour space, exposure, contrast and white balance adjustments have not been applied and the data then reduced to 8 BIT (as with JPGs). The white balance value for example is recorded as an annotation but may be altered after the fact with no penalty. The available loss free compression of DNGs in-camera is new to the M and reflects the greater processing power of the design. There is no downside to that. As Olaf mentions, that note "retains all of the post-editing performed on the image data" is clumsy. I think it refers to the previous non-linear lossy compression to 8 BIT that was standard in the M8 and optional in the M9. Perhaps it might have been better phrased as "retains all of the image data of the (14 BIT) uncompressed DNG for post processing". If you would like to read any of the technical discussions on these subjects, I think you can buy individual issues of LFI as downloads. Quote Link to post Share on other sites More sharing options...
algrove Posted September 15, 2013 Share #8 Posted September 15, 2013 Also search on this forum as there have been MANY discussions about this subject for the M240 as well as previous Leica digital cameras. Quote Link to post Share on other sites More sharing options...
satureyes Posted September 16, 2013 Share #9 Posted September 16, 2013 With the m240 compressed DNG is a lossless compression. A few months ago on these forums a chap was the engineer for Adobe and explained that on the new M the compressed DNG was totally different to that of the M9. The M9 (and I assume M-E) are lossy compressions of DNG. There is apparently no benefit to use uncompressed DNG on the M240. Unless you love filling hard drive space. Compressed DNGs on the M240 are lossless and whatever is removed is then put back. A bit like a zip file. Quote Link to post Share on other sites More sharing options...
algrove Posted September 16, 2013 Share #10 Posted September 16, 2013 I don't want to open this whole discussion again. Why on earth did Leica offer 2 choices here, if the compressed and uncompressed are nearly the same? They should have just compressed all files and made them 24mb instead of 48mb. All RX-1 files are 24's in size. Quote Link to post Share on other sites More sharing options...
jdlaing Posted September 16, 2013 Share #11 Posted September 16, 2013 I don't want to open this whole discussion again. Why on earth did Leica offer 2 choices here, if the compressed and uncompressed are nearly the same? They should have just compressed all files and made them 24mb instead of 48mb. All RX-1 files are 24's in size. It's for a specialized group of people only for one specific use and has no effect on us general photographers whatsoever, or so I have been told. 1 Quote Link to post Share on other sites More sharing options...
algrove Posted September 16, 2013 Share #12 Posted September 16, 2013 It's for a specialized group of people only for one specific use and has no effect on us general photographers whatsoever, or so I have been told. OK, and what specialized group could that be? Thank you. Quote Link to post Share on other sites More sharing options...
jdlaing Posted September 17, 2013 Share #13 Posted September 17, 2013 OK, and what specialized group could that be? Thank you. People looking at images at the very very small cluster of pixel levels. That's all I know. Leica didn't choose the two options. The sensor manufacturer did and Leica probably just kept it. Quote Link to post Share on other sites More sharing options...
algrove Posted September 17, 2013 Share #14 Posted September 17, 2013 Do you refer to those using PS6 and looking at 400x and therefore nearly at the pixel level? Quote Link to post Share on other sites More sharing options...
jdlaing Posted September 17, 2013 Share #15 Posted September 17, 2013 Do you refer to those using PS6 and looking at 400x and therefore nearly at the pixel level? Not entirely but yes in that instance. In my forensics tasks sometimes the reviewers look at uncompressed to see some minor detail on a small portion of an image. I don't know why as I've tried it and can't see the difference between the lossless compressed and uncompressed no matter how mant I see. I suspect Leica's compressed is different than other manufacturers. I don't shoot uncompressed unless specifically asked and then it's a rare occasion. The last time I was asked was on a set of circuit boards where they were checking solder connections and very small resistors. 2 Quote Link to post Share on other sites More sharing options...
algrove Posted September 17, 2013 Share #16 Posted September 17, 2013 Good to hear Dell is looking into the very basics of circuit board deign/manufacture. Quote Link to post Share on other sites More sharing options...
efreed2754 Posted September 17, 2013 Share #17 Posted September 17, 2013 So Lou -- Will you now shoot compressed on your Ms? Ed Quote Link to post Share on other sites More sharing options...
algrove Posted September 17, 2013 Share #18 Posted September 17, 2013 So Lou -- Will you now shoot compressed on your Ms? Ed Probably not. Jeff Schewe suggests that downsampling reduces the original resolution although he does not use the word lossless compression so far and I intend to find out his views on this file type before contemplating a change. From 48mb to 24 must have some effect on images. 1 Quote Link to post Share on other sites More sharing options...
jaapv Posted September 17, 2013 Share #19 Posted September 17, 2013 Lossless compression is not the same as downsampling. 2 Quote Link to post Share on other sites More sharing options...
algrove Posted September 18, 2013 Share #20 Posted September 18, 2013 Lossless compression is not the same as downsampling. Pray tell, what is it then if not down sampling? Quote Link to post Share on other sites More sharing options...
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