How to set a timezone from a filename to adjust dates please ?

[gOgHi]

Hello,

Here is my problem :
  - I create mpeg videos and I can see the tag names "FileModifyDate" and "FileAccessDate" for these files (for example : "2012:11:10 21:01:06+01:00" for both tags)
  - then I rename my mpeg files (for example : "20080724074100.mpg")
  - and, in order to adjust these two tags of my files, I use the command : exiftool -ext .mpg "-FileModifyDate<FileName" .

All seems good except that the timezone has changed from "+01:00" to "+02:00" !
And, using Windows properties, I got for example "24/07/2008 08:41" instead of "24/07/2008 07:41"...

What are the good parameters to adjust the timezone when I change the tag dates of my files using the filename please ?
Changing timezone in Windows before using exiftool doesn't seem to work anymore...

Thank you very much !

In fact, it seems I can disable the automatic adjust "summer-winter" of my Windows system for my clock in order to get "+01:00" for the "FileModifyDate" tag, but I don't want to do that...
When I create my videos files, I got "+01:00" without changing anything into my system...

[Phil Harvey]

All seems good except that the timezone has changed from "+01:00" to "+02:00" !

This is because you changed the date/time to one where daylight savings time applies.

The FileModifyDate is actually stored in the UTC timezone, and ExifTool changes this to the local system timezone when reading.

- Phil