ckchen72 Posted October 21, 2007 Share #1 Posted October 21, 2007 Advertisement (gone after registration) Sorry this is a very basic question. My lens is coded, and the lens detection is on. I open up the image in PS or Bridge, and the ISO is displayed as well as maximum aperture, but the actual fstop I used is not displayed. Is there a way to display this? Thanks! Link to post Share on other sites More sharing options...
Advertisement Posted October 21, 2007 Posted October 21, 2007 Hi ckchen72, Take a look here F stop Metadata. I'm sure you'll find what you were looking for!
Laki Posted October 21, 2007 Share #2 Posted October 21, 2007 no way because the lenses are pure mechanical and dont transmit any data (as long as we talk about m-lenses) Link to post Share on other sites More sharing options...
zeitz Posted October 21, 2007 Share #3 Posted October 21, 2007 Correct, there is no way for the camera to know what aperture is set. Link to post Share on other sites More sharing options...
Guest tummydoc Posted October 21, 2007 Share #4 Posted October 21, 2007 There are some who have asserted they are privvy to un-published information that the blue 'eye' on the front of the M8 measures ambient light and compares it to the TTL meter to make a guess as to the working aperture. Some even claim that they've documented it in test shots. Even if one stretches one's faith in the veracity of certain individuals to accept that this is indeed a fact, the question remains as to whether the parallax between the blue 'eye' and the lens isn't such a significant impediment to accuracy as to make such extrapolation virtually useless. Perhaps the fact that estimated aperture isn't displayed in EXIF is a clue to the resolution of these questions Link to post Share on other sites More sharing options...
luigi bertolotti Posted October 22, 2007 Share #5 Posted October 22, 2007 Yep, I remember an old thread on this possible role of the "blu eye" : my thought is that the f stop could really be computed comparing "blu eye" and TTL measurements, but Leica decided not to implement the function in their Software, for in too many instances (strange light sources, dominant hues, tele lenses...) you should obtain uncorrect results... lacking mech or electronic info directly from diaphragm actuator to body, the "computed" workaround is anyway an untrustable method. Sometimes it would be interesting to have the capabilty to record f stops... I don't remember if some shots of mine were wide open or only next to... but I think we M8 users can live without it, even if it shouldn't be difficult for Leica to add a SW function that allows you to simply "write manually" the info in the EXIF file after the shot. Link to post Share on other sites More sharing options...
dante Posted October 22, 2007 Share #6 Posted October 22, 2007 There are some who have asserted they are privvy to un-published information that the blue 'eye' on the front of the M8 measures ambient light and compares it to the TTL meter to make a guess as to the working aperture. Some even claim that they've documented it in test shots. Even if one stretches one's faith in the veracity of certain individuals to accept that this is indeed a fact, the question remains as to whether the parallax between the blue 'eye' and the lens isn't such a significant impediment to accuracy as to make such extrapolation virtually useless. Perhaps the fact that estimated aperture isn't displayed in EXIF is a clue to the resolution of these questions I wouldn't read too closely into any of this. Contax did use precisely that system to record aperture data in the G series. I always love the assumptions that run through these threads that if Leica doesn't do it, it's invalid/worthless/unnecessary. Link to post Share on other sites More sharing options...
scott kirkpatrick Posted October 22, 2007 Share #7 Posted October 22, 2007 Advertisement (gone after registration) I'm one of the ones making the assertions. It takes some reverse engineering of the private fields in the EXIF to see the estimated aperture. Similarly the unique ID (the number of shutter presses, essentially) is not easily visible although some programs do display it. The estimated aperture can be fooled at very long and very short focal lengths and uneven lighting, but it is usually pretty accurate. If there is enough demand, I am sure that a tool could be created to make both pieces of information more widely available. But it would be still up to the individual to update his EXIF information, and I wouldn't do that to my RAW files. scott Link to post Share on other sites More sharing options...
sandymc Posted October 22, 2007 Share #8 Posted October 22, 2007 I'm one of the ones making the assertions. It takes some reverse engineering of the private fields in the EXIF to see the estimated aperture. Similarly the unique ID (the number of shutter presses, essentially) is not easily visible although some programs do display it. The estimated aperture can be fooled at very long and very short focal lengths and uneven lighting, but it is usually pretty accurate. If there is enough demand, I am sure that a tool could be created to make both pieces of information more widely available. But it would be still up to the individual to update his EXIF information, and I wouldn't do that to my RAW files. scott Scott, As I've communicated privately, I'd be happy to include a makerdata decoding piece into CornerFix............. Sandy Link to post Share on other sites More sharing options...
garyvot Posted October 23, 2007 Share #9 Posted October 23, 2007 Scott, As I've communicated privately, I'd be happy to include a makerdata decoding piece into CornerFix............. Sandy Sandy, this is an excellent idea. I, for one, would be delighted to have the estimated aperture value (if it exists) written to the Exif aperture tag. Even if there is a possibility that it is incorrect, it is much better to have an estimated value than no value at all. Given that CornerFix creates a new DNG file for output, this feature poses no danger to the original file. What can we do to persuade you to do this? Link to post Share on other sites More sharing options...
sandymc Posted October 23, 2007 Share #10 Posted October 23, 2007 Sandy, this is an excellent idea. I, for one, would be delighted to have the estimated aperture value (if it exists) written to the Exif aperture tag. Even if there is a possibility that it is incorrect, it is much better to have an estimated value than no value at all. Given that CornerFix creates a new DNG file for output, this feature poses no danger to the original file. What can we do to persuade you to do this? Its really up to the folks that have decoded the maker data to release their findings on how Leica encodes the data; once they do that I'll incorporate a decoder into CornerFix. Discussions in this regard are ongoing..... Sandy Link to post Share on other sites More sharing options...
isaac Posted October 23, 2007 Share #11 Posted October 23, 2007 Hello Sandy! Its really up to the folks that have decoded the maker data to release their findings on how Leica encodes the data; once they do that I'll incorporate a decoder into CornerFix. Sharing my knowledge... Exif-IFD : 0000:02FC, Entries : 20 1 829A ExposureTime uRatio 1 * 0000:08BC 16666/1000000 [1/60] 2 8822 ExposureProgram uShort 1 v 0000:0003 3 3 8827 ISOSpeedRatings uShort 1 v 0000:04E2 1250 4 9000 Exifversion Undef 4 v 3032:3230 30 32 32 30 5 9004 DateTimeOriginal ASCIIZ 20 * 0000:08C4 2007:10:23 07:54:38 6 9201 ShutterSpeedValue sRatio 1 * 0000:08EC 393216/65536 [6.00] 7 9204 ExposureBias sRatio 1 * 0000:08F4 0/65536 8 9205 MaxAperture uRatio 1 * 0000:08FC 196608/65536 9 9207 MeteringMode uShort 1 v 0000:0002 2 Center 10 9208 LightSource uShort 1 v 0000:0000 0 Unidentified 11 9209 Flash uShort 1 v 0000:0018 24 12 920A FocalLength uRatio 1 * 0000:0904 28000/1000 13 927C MakerNote Undef 220 * 0000:090C 4C 45 49 43 41 00 00 00 0F 00 MakerNote: 0000:090C, Entries : 15 1 0302 0004 0001 0000 0004 0000 2 0303 0004 0001 0000 55e4 002f Serial number 3102180 3 0304 0003 0001 0000 0001 0000 LightSource Daylight 4 0310 0004 0001 0000 0071 0000 2.8/28; 11606 5 0311 000a 0001 0000 00c4 0000 196 6 0312 000a 0001 0000 00cc 0000 204 7 0313 000a 0001 0000 00d4 0000 212 8 0320 0009 0001 0000 0010 0000 9 0321 0004 0001 0000 0000 0000 no auto WB 10 0325 0004 0001 0000 0001 0000 11 0330 0004 0001 0000 0000 0000 12 0331 0004 0001 0000 0001 0000 UV/IR active 13 0332 0004 0001 0000 0000 0000 14 0333 0004 0001 0000 0000 0000 15 0340 0004 0001 0000 0547 0000 00 00 00 00 16 00 00 40 02 00 00 00 01 00 00 76 02 00 00 00 01 00 00 00 05 00 00 00 01 00 ExposureRange -3 - 17EV, LWt 6.00 ExtEV 2.25 IntEV 2.46 FlashEV 5.00 Ext-Int -0.21 MakerNote end Link to post Share on other sites More sharing options...
sandymc Posted October 23, 2007 Share #12 Posted October 23, 2007 Thanks Harald - I believe that some of the guys have worked out how to decode several parts of the makernote - should be interesting. Sandy Link to post Share on other sites More sharing options...
sean_reid Posted October 23, 2007 Share #13 Posted October 23, 2007 There are some who have asserted they are privvy to un-published information that the blue 'eye' on the front of the M8 measures ambient light and compares it to the TTL meter to make a guess as to the working aperture. Again, that information was published by me several months ago. Cheers, Sean Link to post Share on other sites More sharing options...
barjohn Posted October 23, 2007 Share #14 Posted October 23, 2007 Sean, Where did you publish it? Is it on your site or in this forum? Link to post Share on other sites More sharing options...
Guest tummydoc Posted October 23, 2007 Share #15 Posted October 23, 2007 Again, that information was published by me several months ago. Cheers, Sean Sorry I was un-clear. I meant un-published by Leica. Link to post Share on other sites More sharing options...
sean_reid Posted October 23, 2007 Share #16 Posted October 23, 2007 Sean, Where did you publish it? Is it on your site or in this forum? On the site. I think its in the "M8 Updates" article but it might be a different one. I'm not aware of Leica themselves publishing this, I had to seek it out. Cheers, Sean Link to post Share on other sites More sharing options...
DaveSee Posted October 24, 2007 Share #17 Posted October 24, 2007 Hello Sandy! Sharing my knowledge... Thanks! I've hacked /from/ the DNG to assist my scripts and posted earlier about the image orientation fouling customer's view pleasure with Adobe products... what tools are you using to suss EXIF data? Exif-IFD : 0000:02FC, Entries : 20 [snipped] MakerNote: 0000:090C, Entries : 15 1 0302 0004 0001 0000 0004 0000 2 0303 0004 0001 0000 55e4 002f Serial number 3102180 3 0304 0003 0001 0000 0001 0000 LightSource Daylight 4 0310 0004 0001 0000 0071 0000 2.8/28; 11606 ...hmmm, my EXIF reading gives a decimal number at your entry 4 (0x0310) How'd you derive the lens ID? 5 0311 000a 0001 0000 00c4 0000 196 6 0312 000a 0001 0000 00cc 0000 204 7 0313 000a 0001 0000 00d4 0000 212 8 0320 0009 0001 0000 0010 0000 9 0321 0004 0001 0000 0000 0000 no auto WB Again, I get a number resembling the Kelvin temp for your item 9 (0x0321), even when using preset, or manual WB settings... do you get words, or a number? 10 0325 0004 0001 0000 0001 0000 My findings are that your item 10 (0x0325) is a boolean for whether IR/UV is active, and the camera CAN determine the lens+correction algo, and... 11 0330 0004 0001 0000 0000 0000 12 0331 0004 0001 0000 0001 0000 UV/IR active ...your item 12 (0x0331) also seems a boolean, which in my earliest DNGs(12 Nov 06) was always "0", yet now is always "1", even if I disable lens detection. 13 0332 0004 0001 0000 0000 0000 14 0333 0004 0001 0000 0000 0000 15 0340 0004 0001 0000 0547 0000 Your item 15 (0x0340) would appear to be the equivalent to the "ImageUniqueID" 00 00 00 00 16 00 00 40 02 00 00 00 01 00 00 76 02 00 00 00 01 00 00 00 05 00 00 00 01 00 ExposureRange -3 - 17EV, LWt 6.00 ExtEV 2.25 IntEV 2.46 FlashEV 5.00 Ext-Int -0.21 MakerNote end While I suspect there might be some data in the file to determine the aperture, I haven't been able to find it. The most interesting to me, lately, is stuffing the value of 0x0321 into the EXIF "UserComment" field so I have the Kelvin temp in the TIFF or JPEG result of my scripts+"WhiteBalance" to record how WB was determined and truely "AsShot". rgds, Dave Link to post Share on other sites More sharing options...
rob_x2004 Posted October 24, 2007 Share #18 Posted October 24, 2007 Got to respect it Dave. Im standing here like a cave man looking at fire:D. Link to post Share on other sites More sharing options...
barjohn Posted October 24, 2007 Share #19 Posted October 24, 2007 Sean, I checked your M8 Updates article and there is no table. In fact you state that the aperture information is not recorded in the EXIF file. Was your memory slipping or did you actually have the data somewhere else? Link to post Share on other sites More sharing options...
DaveSee Posted October 24, 2007 Share #20 Posted October 24, 2007 Got to respect it Dave. Im standing here like a cave man looking at fire:D. Hey! It's not me fella... Leica left all this in the DNG(and to some extent in the camera's JPEGs)... There are others here who could make more of this stuff, and with thanks, we have a great dataset to pour through our programs. Oddly enough, I'm inclined to get back to film... so I'd have fewer distractions rgds, Dave Link to post Share on other sites More sharing options...
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