wparsonsgisnet Posted October 7, 2009 Share #21 Posted October 7, 2009 Advertisement (gone after registration) Hans, thanks for doing this work. Would you explain where I should discern noise differences between the second 2 graphs? I'm not seeing a big difference. tnx. Link to post Share on other sites More sharing options...
Advertisement Posted October 7, 2009 Posted October 7, 2009 Hi wparsonsgisnet, Take a look here Compressed versus Uncompressed. I'm sure you'll find what you were looking for!
chris_tribble Posted October 7, 2009 Share #22 Posted October 7, 2009 Hans - this is, again, helpful. I'm still torn. Despite all the other things said - including my own comments - I reckon I'm going to be using compressed for most of the time with uncompressed being used when I'm shooting LOW ISO critical work... I'm finding that the combination of write times + download times + post process times doesn't warrant what I'm finding in print's from the M9 - at A3+ (11x16) and even A2 (16x24) I really don't see a difference between output from compressed and uncompressed Leica DNGs... Link to post Share on other sites More sharing options...
ho_co Posted October 8, 2009 Share #23 Posted October 8, 2009 Hans-- This is exactly the kind of rigor I think users of Leica expect, and I know the folks at Solms are glad for any input of this sort to help them find where they've done right and where they've messed up. I'm sincerely glad that you've done this, and that others more knowledgeable than I understand your results. I'm still struggling, and with the pointers Carsten, Michael and Chris have made, I think I'll maybe be along in a bit. Link to post Share on other sites More sharing options...
t024484 Posted October 8, 2009 Author Share #24 Posted October 8, 2009 Hans, thanks for doing this work. Would you explain where I should discern noise differences between the second 2 graphs? I'm not seeing a big difference. tnx. Bill, that is exactly the point,at ISO 640 there is hardly a difference and above ISO 640 there is no difference at all, meaning that uncompressed shooting above ISO 640 does not bring any benefit. Hans - this is, again, helpful. I'm still torn. Despite all the other things said - including my own comments - I reckon I'm going to be using compressed for most of the time with uncompressed being used when I'm shooting LOW ISO critical work... I'm finding that the combination of write times + download times + post process times doesn't warrant what I'm finding in print's from the M9 - at A3+ (11x16) and even A2 (16x24) I really don't see a difference between output from compressed and uncompressed Leica DNGs... Chris, my simulations are confirming my previous guesswork, being that above ISO 640 there is no reason to shoot uncompressed. I must confess on the other hand that I had expected a difference of 1/2 stop at ISO 160 between the two. The difference that has been calculated here is 1/4 stop, which is not that much. But the edge of the lamp from the pictures that you have made available,taken at ISO 400, were showing a noticeable difference to me, although this may be seen as pixel peeping, and not being visible in printed form. So I fully agree with your comment, "use uncompressed only when shooting LOW ISO critical work" Hans. Link to post Share on other sites More sharing options...
t024484 Posted October 8, 2009 Author Share #25 Posted October 8, 2009 Look at the tips of the curves. On the first image, several of the tips are noticeably taller, and in some areas, the tips are much more unruly than in the second image. I presume that this means that both the ultimate magnitude and the general noise levels are higher in the first image. I wouldn't say that the difference in the graph looks huge but I am not sure how this translates to the image. I would have to look at some images myself to make up my mind. From what I saw in the store when I was playing with the M9, I would say that at least 1 stop improvement in the noise levels is a realistic expectation, which makes me happy. Carsten, the first image is the compressed image of image 3, an cannot be compared 1:1 with the other two images. The Vertical axis of the first image is the Square Root of the third image times 4 As an example, SQRT(15.800 *4) = 251. That is how Leica compresses 14 bits to 8 bits. The Second image shows what happens after decompressing the first image, to get the original picture back. Here the operation is the other way round, so to come from image 1 to image 2, every value is raised to the power of two and divided by 4, such as 251*251 / 4= 15750. The point is that the dynamic range stays intact after decompression, but there are only 255 possible values to decompress, instead of the original 16,383 values. You see in the example here that the original 15.800 is reconstructed as 15.750. That is why the decompressed image number 2 is not identical to the uncompressed picture 3. In a lossless compression, there had not been any difference at all. But I can only repeat that the images are just meant to make a visualisation of the compression / decompression process. A picture says more than a thousand words so to say. Hans Link to post Share on other sites More sharing options...
carstenw Posted October 8, 2009 Share #26 Posted October 8, 2009 Carsten, the first image is the compressed image of image 3, an cannot be compared 1:1 with the other two images. Sorry, I was being vague. I meant the first image of the last two. I wasn't describing the actual first image in my post at all. Link to post Share on other sites More sharing options...
chris_tribble Posted October 8, 2009 Share #27 Posted October 8, 2009 Advertisement (gone after registration) So I fully agree with your comment, "use uncompressed only when shooting LOW ISO critical work" Hans. Hans - again - thanks for the comments. This has been an interesting interlude. A little further playing below makes me think that a lot of the problem is in the LR Calibration Profile - IF others agree, could Jono / Sean / any others with a direct line to Valhalla (Solms) PLEASE pass this on to those who are working with Adobe on this... Results are below using the M9 + 50mm Lux + the 5D mk2 with a 28-70 set to 50mm - both cameras at F4. A. First pair are straight fromin-camera AWB B. Second pair are with Lightroom Auto WB applied + a PROFILE adjustment to the green channel in LR (+38 Hue / - 21 Saturation) for the M9 image C. Third whole scene is the M9 with Lightroom auto WB applied but no profile adjustment. D. Final pair are 100% crops from M9 (calibration adjusted) and 5Dmk2 Lessons? 1/ For me, the yellow patching is significantly reduced in the calibration adjusted image. 2/ NEITHER image is perfect ideal - but they'd be useable if you needed a colour rendition of this scene 3/ AWB out of the M9 and the 5D2 both leave a lot to be desired () 4/ Noisewise - the M9 compares REALLY favourably with the King of the hill in this test. Main thing is we REALLY need Leica to offer some improved calibration models in DIFFERENT light conditions. At the very least we need calibration profiles for: Daylight Portraiture (emphasis on skin tones) Tungsten Fluorescent I've still not found my colour checker chart - I'd have a go if I had one. It seems really important that Leica support us on getting this right. I understand that this is a real torture test AND that a lot of people out there can do a better job than I can on this - I'm no ACR expert - but I hope it's setting some wheels turning... BTW - if anyone else wants to play with these I've posted DNGs to http://dl.getdropbox.com/u/862415/Leica_M9/high_iso_Leica_Canon.zip 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! 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/99241-compressed-versus-uncompressed/?do=findComment&comment=1066757'>More sharing options...
carstenw Posted October 8, 2009 Share #28 Posted October 8, 2009 In those last two crops, did you really boost the green channel by +38? To me it looks too green... look at the edges of the microwave. Link to post Share on other sites More sharing options...
fishblimp Posted October 8, 2009 Share #29 Posted October 8, 2009 Let's say I've shot uncompressed and then I import my images into LightRoom. After reviewing my images, I then decide that some (if not most) don't need to be uncompressed. Is there a way to somewhat easily convert them to compressed? Is it ok to compress through the export feature in LR? Or does a different program (i.e Photoshop) do a better job of compressing? Could a batch or droplet be made to do this (in case there were a lot of files to compress)? Link to post Share on other sites More sharing options...
chris_tribble Posted October 8, 2009 Share #30 Posted October 8, 2009 In those last two crops, did you really boost the green channel by +38? To me it looks too green... look at the edges of the microwave. Carsten - I did - and I wouldn't dream of doing it in normal circumstances - just trying to get some that looked better over all... the hazards of pixel peeping... Looking at the 5D2 file alongside the M9, I think the main need is an improvement in the Lightroom profiles - or, as I said, a set of LR profiles - one "neutral" and then another set of other purposes. Adobe / Canon offer something along these lines for the 5D2 (neutral, landscape, portrait, faithful). My feeling is that the current Neutral profile needs improving + we would benefit from a similar choice to the above for the M9. Let's say I've shot uncompressed and then I import my images into LightRoom. After reviewing my images, I then decide that some (if not most) don't need to be uncompressed. Is there a way to somewhat easily convert them to compressed? Is it ok to compress through the export feature in LR? Or does a different program (i.e Photoshop) do a better job of compressing? Could a batch or droplet be made to do this (in case there were a lot of files to compress)? Hi - fishblimp???? It's possible in LR to select images and then (in the Library Module) to use Library > Convert Photo to DNG. If you apply this to Leica DNGs it converts them to Adobe's compressed version. NB - although this reduces file size, it's not the same as selecting in-camera compression - this produces a smaller filesize and works in a different way - and it can't be done off camera. Link to post Share on other sites More sharing options...
t024484 Posted October 8, 2009 Author Share #31 Posted October 8, 2009 Chris, I just made a correction with the White Balance Selector in LR on the white edge of the magnetron, and everything looks fine to me. No further action taken. Hans 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! 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/99241-compressed-versus-uncompressed/?do=findComment&comment=1066963'>More sharing options...
chris_tribble Posted October 8, 2009 Share #32 Posted October 8, 2009 Hans - taking a white point from the microwave works, but there are still major issues. In the example below, the first image is 5D2, the second M9. First, the wooden work surface is way too yellow - also don't you see the yellow blotching on the wall? If you look at the Canon and Leica side-by-side you can see that the yellow is an issue in the M9 version (especially) in the shadow areas by the micro-wave. Of course neither camera is getting it "right" (this is probably impossible in this lighting). We have to remember that the wall is a light gray in daylight. I'm certainly not flagging this as a huge M9 issue - but it would be really nice if we could get IQ better in these horrible conditions through firmware or a better profile. BTW - if there are any C1 experts following this, I'd be interested to see what results you get with the two images. The raws are still at: http://dl.getdropbox.com/u/862415/Leica_M9/high_iso_Leica_Canon.zip ... 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! 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/99241-compressed-versus-uncompressed/?do=findComment&comment=1067014'>More sharing options...
ArtZ Posted October 8, 2009 Share #33 Posted October 8, 2009 Hans - taking a white point from the microwave works, but there are still major issues. In the example below, the first image is 5D2, the second M9. First, the wooden work surface is way too yellow - also don't you see the yellow blotching on the wall? If you look at the Canon and Leica side-by-side you can see that the yellow is an issue in the M9 version (especially) in the shadow areas by the micro-wave. Of course neither camera is getting it "right" (this is probably impossible in this lighting). We have to remember that the wall is a light gray in daylight. I'm certainly not flagging this as a huge M9 issue - but it would be really nice if we could get IQ better in these horrible conditions through firmware or a better profile. BTW - if there are any C1 experts following this, I'd be interested to see what results you get with the two images. The raws are still at: http://dl.getdropbox.com/u/862415/Leica_M9/high_iso_Leica_Canon.zip ... Well, I think this issue is due to the differences of CMOS vs CCD sensors. For these kind of situations, CMOS sensors can manage better noise than CCD sensors. I´m not surprised the 5DMKII behaves better. Another exemple could be "blooming" (the blue/purple fringe found in digital camera pictures using CCD sensors, especially on high contrast situations -or under conditions in which either the finite charge capacity of individual photodiodes, or the maximum charge transfer capacity of the CCD, is reached). CMOS generally has natural blooming immunity. CCDs, on the other hand, require specific engineering to achieve this capability. The M8 sensor is very sensitive to blooming... Link to post Share on other sites More sharing options...
malcolm Posted October 8, 2009 Share #34 Posted October 8, 2009 Quote: BTW - if there are any C1 experts following this, I'd be interested to see what results you get with the two images. The raws are still at: http://dl.getdropbox.com/u/862415/Le...eica_Canon.zip ... Chris, I'm far from a C1 expert, but here's my post to your "M9 - Low light, artificial light white balance" thread: Quote: Originally Posted by malcolm View Post Chris, Thanks for all your postings on this subject. I've downloaded all the ISO 1600 files, and note that they are 10.3 Mb in size - so they must have been reduced from the originals (in Lightroom?). Were the originals made in compressed or uncompressed mode? Opening only the 1/90 sec. AWB image in Capture One 4.8.3, the profile defaults to "DNG neutral". I saved this as a TIFF file, and then used C1's "M9" profile. The M9 profile produces some color shift, but also seems to introduce considerable noise (sharpening disabled, all noise sliders set to "0"). Anyone else tried this? Same or different results? Update. When opening the TIFF files in Photoshop (CS4 Demo), just the opposite happens: the M9 profile image has a more neutral color balance, and much less noise. Now I'm really puzzled. Link to post Share on other sites More sharing options...
sandymc Posted October 8, 2009 Share #35 Posted October 8, 2009 Thanks for all your postings on this subject. I've downloaded all the ISO 1600 files, and note that they are 10.3 Mb in size - so they must have been reduced from the originals (in Lightroom?). Were the originals made in compressed or uncompressed mode?Opening only the 1/90 sec. AWB image in Capture One 4.8.3, the profile defaults to "DNG neutral". I saved this as a TIFF file, and then used C1's "M9" profile. The M9 profile produces some color shift, but also seems to introduce considerable noise (sharpening disabled, all noise sliders set to "0"). Anyone else tried this? Same or different results? Update. When opening the TIFF files in Photoshop (CS4 Demo), just the opposite happens: the M9 profile image has a more neutral color balance, and much less noise. Now I'm really puzzled. A 10.3Mb image is one that has almost certainly been compressed in Lightroom (or ACR). There is a issue with C1 reading images that have been compressed by Lightroom; you can get color shifts - see here: http://www.l-camera-forum.com/leica-forum/leica-m9-forum/98212-lightoom-mangling-m9-images-there-compression.html Sandy Link to post Share on other sites More sharing options...
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