Phil, I have an image which was shot by Canon t1i (500D) with ISO set to 100.
Canon Shot Info (from -U -v3) shows
3) CanonShotInfo (SubDirectory) -->
| | | - Tag 0x0004 (68 bytes, int16u[34]):
| | | 0562: 44 00 00 00 a0 00 f8 00 80 00 20 01 f4 ff 00 00 [D......... .....]
| | | 0572: 03 00 00 00 08 00 08 00 9b 00 00 00 00 00 00 00 [................]
| | | 0582: 00 00 00 00 01 00 00 00 00 00 80 00 24 01 96 00 [............$...]
| | | 0592: 00 00 00 00 f8 00 ff ff ff ff ff ff ff ff 00 00 [................]
| | | 05a2: 00 00 00 00 [....]
| | | + [BinaryData directory, 68 bytes]
| | | | AutoISO = 0
| | | | - Tag 0x0001 (2 bytes, int16s[1]):
| | | | 0564: 00 00 [..]
| | | | BaseISO = 160
| | | | - Tag 0x0002 (2 bytes, int16s[1]):
| | | | 0566: a0 00 [..]
So if we decode them using
fValue=(lValue/32.0f*log(2.f))*100; (my code)
or ValueConv => 'exp($val/32*log(2))*100' (%Image::ExifTool::Canon::ShotInfo) we get
AutoISO=0 and BaseISO=347, But basic -all gives
Auto ISO : 100
Base ISO : 100
I don't see any defaulting to 100 in %Image::ExifTool::Canon::ShotInfo.
Where is it getting converted to 100?
I think you forgot the last /32.
The conversion for BaseISO is exp($val/32*log(2))*100/32.
Which is different from the conversion for AutoISO.
Figuring out these conversions is why I get the big bucks. ;) Hey, wait! I do this for free... :P
- Phil
See, see... did I just noticed great sense of humor? :)
I am feeling ashamed, i misread "exp" function to be PERL equivalent of "eval" in javascript, so in my conversion I totally missed e^lValue/32.0f*log(2.f), and just considered lValue/32.0f*log(2.f). So stupid!! after adding "exp" to my code too I am matching the results. :D
Thank you for your guidance.. btw can you imagine if you have charged few bucks for each new tag for each user.. you could have retired by now :)
About retiring: I have calculated that if I received 25 cents for every exiftool download I could live off that income. (And that is just the exiftool home site -- I'm not even counting downloads from any of the dozens of other sites hosting versions of exiftool for download.) The number of downloads is just crazy. I can't believe that many people are actually using my tool.
- Phil