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For others, they can be vastly different. The result, when I calculate Bv, is 3.51 the EXIF data have -2.30.įor some images, the calculated and reported values are fairly close. I am just now looking at a shot taken with A=6.50 T=0.06250s Sx=200 N=0.297 I found that it seems to be approximately correct, i.e. I do not know anything about this formula, but I was intrigued by it and so checked it on a few of my images. ![]() ![]() #How to use exiftool pattern not found iso#I found that it seems to be approximately correct, i.e.īv = log2(A^2/(T * Sx)) + log2(1/0.297) =>Ĭan you tell us an example where this is not approximately good?īTW, I expect that the formula holds approximately because the ISO and/or speed are not reported accurately but as approximations to well known values. I do not know anything about this formula, but I was intrigued by it and so checked it on a few of my images. I'd appreciate it very much if anyone could show me the light. When I use the values in the EXIF data for f-number, exposure time, ISO, as well as N, the result is not equal to the brightness value in the EXIF data. ![]() I'd appreciate it very much if anyone could show me the light. When I use the values in the EXIF data for f-number, exposure time, ISO, as well as N, the result is not equal to the brightness value in the EXIF data. I am using the standard formula Bv = log2 (A²/T/Sx/N)īv: brightness value A: f-number T: exposure time Sx: ISO N: constant that establishes the relationship between the ASA arithmetic film speed Sx and the ASA speed value Sv, which is 2^(-7/4) = 0.297. There is some inconsistency in the EXIF information, a hidden assumption (hidden to me, anyway), a hardware-related constant that eludes me and that needs to be included in the calculation, or something else I am missing. I would like to calculate this value from other information in the EXIF data, according to APEX definitions. The EXIF data include the "Brightness Value" that the camera recorded for the given image. That will load up the XMP gps tags.I am trying to make sense of exposure-related entries in the EXIF data for my X-E1. #How to use exiftool pattern not found full#The first column would have to be the full path to the source file. Date wouldn't be necessary, unless you need to change the date. The first row would have to be "SourceFile,XMP:GPSLongitude,XMP:GPSLatitude". XMP gps tags will take negative coordinates, but EXIF gps tags only accept positive numbers and need the directional reference tag to be accurate.įirst off, there would have to be some changes to CSV. I could also create a batch script to use Exiftool from the command line, which I can probably figure out on my own in due time but to someone who doesn't deal with EXIF data regularly, the sheer number of tags, command-line arguments and options available in Exiftool is a bit daunting.ĮxifTool could do this, but the use of negative coordinates might make it a two step procedure depending upon what tags you want to use. #How to use exiftool pattern not found how to#I've found the Exiftool GUI, which has the ability to copy metadata from an XMP file to the appropriate JPG, but I don't know how to get my table into a set of XMP files in order to take advantage of that. Obviously, I could edit the EXIF metadata manually and copy and paste each set of coordinates into the appropriate EXIF tags, but I was hoping to find a way to do it automatically. ![]()
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