biogon Posted March 8, 2013 Share #1 Posted March 8, 2013 (edited) Advertisement (gone after registration) Hello everybody! Apparently Leica in the M has changed the way of numbering shots in the "Image Unique ID" field of the exif data, the M8/M9 Hexadecimal numbering is no longer being used. Now we have there what appears to be a random decimal number, not correlated with the number of shots taken by that camera. Does anyone know whether that number is really random (not completely because it should anyway remain unique, I surmise), or a hidden code exists allowing to tell how many shots the camera has taken? Thank you and all the best. Edited March 8, 2013 by biogon Quote Link to post Share on other sites More sharing options...
Advertisement Posted March 8, 2013 Posted March 8, 2013 Hi biogon, Take a look here Leica M (240) Image Unique ID. I'm sure you'll find what you were looking for!
BerndReini Posted March 9, 2013 Share #2 Posted March 9, 2013 I don't really know the answer to your question as far as shutter actuations, but you could actually do the same thing with the M9 with a little workaround: you just had to renumber a picture on the SD card in your computer, then continue shooting with the M9 and it would follow in consecutive numbers for file naming after this last renumbered picture. Quote Link to post Share on other sites More sharing options...
thighslapper Posted March 10, 2013 Share #3 Posted March 10, 2013 Biogon...... You are quite correct ..... and the behaviour is not quite random..... I seems to reset every time the camera is switched off (or possibly in standby too)..... and then produces unique id's with rising numbers but not in any sensible sequence starting at some random point ranging from the low thousands to several millions...... eg... (pic then unique id) 170 2274331 171 2314332 172 2388281 173 2435851 174 2537540 175 2601900 etc next day: 207 95847 208 219539 209 404396 210 564961 etc today: 233 6280 234 119385 camera off 235 37013 236 67552 237 143641 238 226094 etc..... there is another number in the exif - unique raw id ...... but that has a basic form of 30303030303030x3x3x3x3x3x..... where the x bits are in fact the image unique id (ie all the alternate 3's stripped out) ...... so you are correct .... without a degree in cryptography it looks impossible to tell how many actuations a camera has had........ .... and there is some sense in that ...... I returned my 'as new' ex demo M9 when I discovered it had in fact over 5000 actuations recorded .... which I argued made it 'second hand' ....... and got a new M9 for my trouble...... very interesting...... Quote Link to post Share on other sites More sharing options...
biogon Posted March 10, 2013 Author Share #4 Posted March 10, 2013 very interesting...... Yes, indeed... Thank you so much thighslapper! Your message is a very good starting point toward understanding. Quote Link to post Share on other sites More sharing options...
pico Posted March 10, 2013 Share #5 Posted March 10, 2013 (edited) Oh, thighslapper, now you have done it - teased a decoder. The numbers past the sequence # cannot be pseudo-random for a number of reasons besides the fact that they are tied to the system hardware. For one, they increase with each new sequence # from power-on. Someone with more time and brains that I have will figure it out. Edited March 10, 2013 by pico Quote Link to post Share on other sites More sharing options...
thighslapper Posted March 10, 2013 Share #6 Posted March 10, 2013 A BIG clue........ I fiddled about with this camera when I got it and reset the numbering to be 400Leica as the start folder and numbering to start from 4000001.... (so the numbers are unique and don't double up on previous M's) This file has NO EXIF unique RAW id The unique file id however is 00000000000000000000000000002cd1 no other alphanumeric coding features in any subsequent exif file id info..... this one presumably seeds the whole of the subsequent numbering process.... 3 Quote Link to post Share on other sites More sharing options...
biogon Posted March 11, 2013 Author Share #7 Posted March 11, 2013 Advertisement (gone after registration) 2cd1 hexadecimal in a M8/M9 body would correspond to 11473 shots. Is that number a reasonable estimate of the pictures you have already taken with your M 240 thighslapper? What happens if you restore the default folder/numbering? The camera would resume generating semi-random decimal IDs, or will retain the hexadecimal numbering system? Quote Link to post Share on other sites More sharing options...
wlaidlaw Posted March 11, 2013 Share #8 Posted March 11, 2013 Could a date be being incorporated into the unique ID or alternatively, could this be linked to the GPS function, which will become available when the multifunction grips start to arrive? I was thinking that the unique ID = shutter actuation number + hexadecimal date (with start point ???) Wilson Quote Link to post Share on other sites More sharing options...
thighslapper Posted March 11, 2013 Share #9 Posted March 11, 2013 (edited) apologies folks ....... 2cd1 is picture no. 1 when I reset everything and set up my own folder with my own numbering. It was an M9 image I copied to the card and renumbered to seed the numbering sequence ......... and in fact it did this as per the behaviour of the M9 The original date on the first few pictures was 2008 (I forgot to set it) .... and I again I reset the time a day later (I was 12hrs adrift as I hadn't set it to 24hr clock) and it seems to make no difference to the pattern of numbering..... I am not going to restore the default numbering to investigate further ........ there are a number of glitches in the way the system works ..... the main one being it works independently for each camera profile .... and when I did this before it resulted in me having to re-enter everything for each profile and then take a load of blank pictures to bring me up to my original numbering ..... you would have to fiddle with this camera to understand how this works .... but basically the file folder and file numbering is not a global setting.... We need someone who is a mathematician to explain how you can set up an apparently random numbering system that will always produce unique numbers ....... date and time seems a bit flaky as you could reset the cameras time/date ..... unless it registers elapsed time since 'birth'. Presumably there is some loook up table that provides a multplier or offset that generates the final number........ Although the numbers seem to rise when in continuous use the jumps are pretty random ....... I will post some screenshots of the full exif data later and see if someone spots something..... Edited March 11, 2013 by thighslapper 2 Quote Link to post Share on other sites More sharing options...
thighslapper Posted March 11, 2013 Share #10 Posted March 11, 2013 exif data : 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! 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/200020-leica-m-240-image-unique-id/?do=findComment&comment=2267964'>More sharing options...
biogon Posted March 11, 2013 Author Share #11 Posted March 11, 2013 My question arose from looking at the exif data of some of the dng pictures posted by Ming Thein (Flickr: mingthein's Photostream), I do not own a M 240 (yet! ). In case they would help, I am listing their image numbers and corresponding Image Unique IDs below: 10 79393 22 754035 26 270199 27 344698 37 106609 41 123032 58 1014633 79 298026 85 313374 88 4718 95 517834 108 617410 111 194886 217 488822 249 424922 253 94525 278 523946 280 108239 282 45770 295 428897 305 276703 325 245075 334 179411 346 185423 362 421215 364 543819 373 260589 422 335311 429 316729 437 423110 438 491976 444 879230 457 531080 498 1845810 548 318712 563 319833 584 76126 733 117764 1273 114473 1336 506172 1348 761738 1362 869199 1364 90199 2115 78763 2230 164980 2250 154542 2423 458802 2505 455409 2532 74702 2887 926509 3101 259258 3108 218801 3143 2154800 3155 59695 3458 2564511 3492 4822417 3517 6475792 3532 90915 3539 559744 3641 2029507 3792 396759 3828 811918 4436 182029 4443 643539 4497 638831 4609 69941 4662 343922 4666 128843 4678 858528 Quote Link to post Share on other sites More sharing options...
wlaidlaw Posted March 11, 2013 Share #12 Posted March 11, 2013 My question arose from looking at the exif data of some of the dng pictures posted by Ming Thein (Flickr: mingthein's Photostream), I do not own a M 240 (yet! ). In case they would help, I am listing their image numbers and corresponding Image Unique IDs below: 10 79393 22 754035 26 270199 27 344698 37 106609 41 123032 58 1014633 79 298026 85 313374 88 4718 95 517834 108 617410 111 194886 217 488822 249 424922 253 94525 278 523946 280 108239 282 45770 295 428897 305 276703 325 245075 334 179411 346 185423 362 421215 364 543819 373 260589 422 335311 429 316729 437 423110 438 491976 444 879230 457 531080 498 1845810 548 318712 563 319833 584 76126 733 117764 1273 114473 1336 506172 1348 761738 1362 869199 1364 90199 2115 78763 2230 164980 2250 154542 2423 458802 2505 455409 2532 74702 2887 926509 3101 259258 3108 218801 3143 2154800 3155 59695 3458 2564511 3492 4822417 3517 6475792 3532 90915 3539 559744 3641 2029507 3792 396759 3828 811918 4436 182029 4443 643539 4497 638831 4609 69941 4662 343922 4666 128843 4678 858528 Where is Alan Turing when you need him? Wilson 4 Quote Link to post Share on other sites More sharing options...
pico Posted March 11, 2013 Share #13 Posted March 11, 2013 (edited) Could a date be being incorporated into the unique ID or alternatively, could this be linked to the GPS function, which will become available when the multifunction grips start to arrive? I was thinking that the unique ID = shutter actuation number + hexadecimal date (with start point ???) Wilson It seems unlikely that there's a date in there. I'm quite familiar with a few date coding methods, for example those that store a date as seconds since Jan 1, (whatever year). It is not HEX, either. thighslapper: We need someone who is a mathematician to explain how you can set up an apparently random numbering system that will always produce unique numbers That's 'random without replacement' and it can be done, and part of the sequence will reveal the technique. ....... date and time seems a bit flaky as you could reset the cameras time/date ..... unless it registers elapsed time since 'birth'. hundredths of a second (or clock ticks) since manufacture is a cool idea, however some of the numbers are too small to be date/time. Biogon - thanks for going through the trouble of gathering the new numbers, but it would help a great deal if they were perfectly sequential. Edited March 11, 2013 by pico Quote Link to post Share on other sites More sharing options...
biogon Posted March 11, 2013 Author Share #14 Posted March 11, 2013 Biogon - thanks for going through the trouble of gathering the new numbers, but it would help a great deal if they were perfectly sequential. I agree. But as I said I do not own a M 240, and those numbers are all I could get a few days ago from the Ming Thein's site. Any other M 240 owner willing to contribute to the M240 cryptanalysis? 1 Quote Link to post Share on other sites More sharing options...
wlaidlaw Posted March 11, 2013 Share #15 Posted March 11, 2013 I agree. But as I said I do not own a M 240, and those numbers are all I could get a few days ago from the Ming Thein's site. Any other M 240 owner willing to contribute to the M240 cryptanalysis? What do you want? Wilson Quote Link to post Share on other sites More sharing options...
thighslapper Posted March 11, 2013 Share #16 Posted March 11, 2013 Perhaps someone could ask the nice Leica people in Solms ......... There seems to be a determined effort at obscurity here ..... so I doubt they will reveal all.... but they might divulge the rationale behind why they have done this..... Quote Link to post Share on other sites More sharing options...
biogon Posted March 11, 2013 Author Share #17 Posted March 11, 2013 What do you want? What Pico is saying he needs: a pretty long list of perfectly sequential image numbers from M 240 with corresponding Image Unique IDs... Quote Link to post Share on other sites More sharing options...
biogon Posted July 16, 2013 Author Share #18 Posted July 16, 2013 Biogon - thanks for going through the trouble of gathering the new numbers, but it would help a great deal if they were perfectly sequential. Hello, I resurrect this thread because I finally found a list of sequential Image Unique ID from M Typ 240 pictures (only No. 5 is missing because it corresponds to a video file). https://dl.dropboxusercontent.com/u/100811023/M240_IUIDs.txt I look forward that they may help in deciphering the mystery... 2 Quote Link to post Share on other sites More sharing options...
Guest JonathanP Posted August 21, 2014 Share #19 Posted August 21, 2014 and the behaviour is not quite random..... I seems to reset every time the camera is switched off (or possibly in standby too)..... and then produces unique id's with rising numbers but not in any sensible sequence starting at some random point ranging from the low thousands to several millions...... I think you're correct. Sampling some of my images I think the number is time from camera switch on, incremented at a rate around 1500/sec. I haven't ascertained yet if the count continues whilst it sleeps, but switching off seems to reset it. I know its nice to speculate that there's a clever scheme here to encode the shutter count, but come on - we're talking Leica software engineering. All they need for the ImageUniqueID exif tag is a number with a reasonable chance of not being duplicated - why not just sample an internal processor tick count at some point in the image taking process? They haven't even bothered to store the number in non-volatile memory to carry on when next switched on, which given the size of the field would have pretty much guaranteed uniqueness. I'm sorry but Leica doesn't have a track record in software excellence, so my money's on the under-engineered, get away with the minimum possible solution Jonathan Quote Link to post Share on other sites More sharing options...
CheshireCat Posted August 22, 2014 Share #20 Posted August 22, 2014 (edited) I'm sorry but Leica doesn't have a track record in software excellence, so my money's on the under-engineered, get away with the minimum possible solution +1 A proper algorithm would use: - Camera serial number (unique globally - all Leica cameras). - Shutter count (unique locally - your camera). And given the fact I see in this thread a "663" number reported by biogon, it is extremely unlikely that Leica "engineers" are doing anything like that. Edited August 22, 2014 by CheshireCat Quote Link to post Share on other sites More sharing options...
Recommended Posts
Join the conversation
You can post now and register later. If you have an account, sign in now to post with your account.
Note: Your post will require moderator approval before it will be visible.