Guest trond Posted February 1, 2010 Share #1 Posted February 1, 2010 Advertisement (gone after registration) I have noticed that the EXIF data from M9 is sometimes incorrect (or is it LightRoom?). For example, the M9 info screen can show the shutter speed as 1/24s, while the EIXF data in LightRoom shows the shutter speed as 1/20s. This is 100% repeatable, and happen also on other "half step" shutterspeeds on my M9. Also, I have noticed, four times in approximately 1000 pictures, that lens information is missing form the EXIF. This happens both with manual lens select, and with lens detection set to auto. This seem to affect pictures at random, as only one picture in a series, has the lens info missing, while a picture taken a few seconds before or after, has the correct lens info recorded in the EXIF. Anyone else experienced these problems? Best regards Trond Link to post Share on other sites More sharing options...
Advertisement Posted February 1, 2010 Posted February 1, 2010 Hi Guest trond, Take a look here Stange EXIF data from M9?. I'm sure you'll find what you were looking for!
vanhulsenbeek Posted February 1, 2010 Share #2 Posted February 1, 2010 Lots of threads going on about these problems. Just scroll down and see! Or use the forum-search. Link to post Share on other sites More sharing options...
FredSF Posted February 1, 2010 Share #3 Posted February 1, 2010 I've noticed that as well, however... Is that so important to make the difference between 1/24 or 1/20 of a sec.? Seriously, imagine for a minute EXIF didn't exist, how would you do? Probably like us ole' folks using film in da ole' daze... You like what you shoot? Content yourself, and by all means enjoy what you're doing. :cool: Link to post Share on other sites More sharing options...
Guest trond Posted February 1, 2010 Share #4 Posted February 1, 2010 Not terribly important! However, I would like that whatever information is recorded in the EXIF, to be accurate, or just left out. Love the M9 and Leica lenses though! Best regards Trond Link to post Share on other sites More sharing options...
lars_bergquist Posted February 1, 2010 Share #5 Posted February 1, 2010 [ ... ]Also, I have noticed, four times in approximately 1000 pictures, that lens information is missing form the EXIF. This happens both with manual lens select, and with lens detection set to auto. This seem to affect pictures at random, as only one picture in a series, has the lens info missing, while a picture taken a few seconds before or after, has the correct lens info recorded in the EXIF. Anyone else experienced these problems? Best regards Trond Yes, occasionally, when the M9 has just been aroused from sleep, or when a new lens has been mounted, both the Info screen and the EXIF data show the lens as "uncoded". This has happened both with a 35mm Summilux ASPH and a 28mm Summicron ASPH, both 'retro-coded' by Leica. What is more, the pictures show that the appropriate corrections for light fall-off have not been applied. In my case too, the next frame is correct. I suspect this is a firmware bug, and I hope it will be attended to in the coming firmware update. The old man from the Age when Hardware Meant Ironmongery Link to post Share on other sites More sharing options...
cbretteville Posted February 4, 2010 Share #6 Posted February 4, 2010 Not terribly important!However, I would like that whatever information is recorded in the EXIF, to be accurate, or just left out. Trond, The information is accurate, its the presentation of it that varies. The exif info that relates to aperture and shutter speeds is recorded using a complex data type that means the value you're shown has to be calculated from raw data and then rounded off in the presentation layer (i.e., LR or the back of the camera) to be shown as "1/20". The underlying information will be the same, but it is up to the programmer to decide how to display the result of the calculation that is necessary to display a value that is human readable. This is all in line with the exif specification. Carl Link to post Share on other sites More sharing options...
Guest trond Posted February 4, 2010 Share #7 Posted February 4, 2010 Advertisement (gone after registration) Electronic measurement of timing in the range we speak about here is trivial and easy to perform accurately. The M9 spec from Leica states manual shutter speed in "half" step increments. the correct half step exposure above 1/30 seconds, is 1/20 seconds as reported by LightRoom. The info display on the M9 shows 1/24s, which is wrong, since this is 1/4 step above 1/30. If this was correct, it does not match the 1/2 step increments of the Leica lenses. I think therefore, that this is one of the many firmware bugs in the M9, showing a significantly wrong shutter speed on the M9 info display. EXIF is probably correct since LightRoom showns the correct "half" step speed. Best regards Trond Link to post Share on other sites More sharing options...
scott kirkpatrick Posted February 4, 2010 Share #8 Posted February 4, 2010 I don't think you are following Carl's point. Information about the shutter speed is not a measurement at all. It is settings that are passed to the shutter controller, and posted in the EXIF in various ways. If you look at a full EXIF decode there are frequently two distinct values of the shutter speed displayed. I believe one is more approximate, and is passed as a value from a table, while the other, the one Carl described, is a fraction, the ratio of two numbers (also from tables) which must be calculated and expressed in ASCII characters in the info display and in the EXIF that LR or C1 shows you. Cameras are just not scientific instruments. scott Link to post Share on other sites More sharing options...
Guest trond Posted February 4, 2010 Share #9 Posted February 4, 2010 The shutter controller in an electronically controlled shutter also measures the actual shutter speed, and closes the shutter when the set time is reached. This is done either mechanically by the shutter (usually the leading edge of the exposure), or electronically by the sensor strobe timing (usually the trailing edge of the exposure), as in cameras with live view. In a electronically controlled mechanical shutter, this is done to compensate for temperature effects and aging effects over time, so the shutter speed always will be as accurate as possible. Again, the setting AND control of a shutter speed of 1/20s, or even 1/4000s, is a trivial technical task. I am not familiar with the format of the EXIF data, but: If the shutter speed data field contains two different shutter speeds, I would expect one to be the set shutter speed, and the other to be the actual shutter speed, as measured by the feedback system in the shutter timing controller. So, if the set speed by the camera is 1/24s, this is just plain wrong, according to "standard half step" shutter speed increments. If the set speed is correctly 1/20s, and the ACTUAL shutter speed is determined as 1/24s, the error is just too big for a new camera with only 1000 total exposures. Best regards Trond Link to post Share on other sites More sharing options...
sandymc Posted February 4, 2010 Share #10 Posted February 4, 2010 Trond, Scott is entirely correct about there being two values in the DNG file. They are respectively ExposureTime and ShutterSpeedValue - I'd suggest using a tool that can read exif data to look at both before assuming that's there's anything more complex than different rounding happening here - ExposureTime is coded as a rational, and ShutterSpeedValue as an APEX value, so you will, at the best of times, get variations in what is displayed. Either ExifTool or CornerFix (if you select verbose mode) will give you both values. Sandy Link to post Share on other sites More sharing options...
cbretteville Posted February 4, 2010 Share #11 Posted February 4, 2010 Trond, Looking at decodes from M9 files (the M8 is the same as far as I can remember) there are two different representations of the time interval shutter was open for the exposure. One is called "Exposure time", the other "Shutter speed". The data the calculations are based on are stored as separate values and the equations used to calculate the results are different. Why this is so I have no idea, but the exif and tiff specs are full of such things. If you want me to I can dig the raw data out of your file(s) for you and tell you what is recorded in the exif blocks. PM me and we'll exchange email addresses. Carl Link to post Share on other sites More sharing options...
Guest trond Posted February 4, 2010 Share #12 Posted February 4, 2010 I used ExifTool to dump the info of a few M9 files, and as you state there are two fields; "Exposure Time" and "Shutter Speed Value". On all the files I checked, the displayed vale for both are exactly the same in ExifTool, and the value is shown as a fraction. I will check later this evening if this info is the same as shown on the M9 screen. Best regards Trond PS: Regarding PM, this does not seem to work from my forum account, check your facebook inboks. Link to post Share on other sites More sharing options...
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