There are two things of importance here:
1. The camera time zone. The camera wrote a timstamp, but did not specify what time zone was used. Thus HoudahGeo needs to ask. Knowing the camera time zone, it can make sense of the timestamp. E.g. know that 7 hours need to be added to get a GMT timestamp.
2. The time zone used for displaying the timestamp. This usually is your computer's time zone. But this may be adjusted using the pop-up menu in the top right corner of the HoudahGeo window. This setting does not change the timestamps in any way. It just specifies how these should be displayed.
Thus: timestamps will appear the same in camera and on the computer of both camera time zone and display time zone are the same.
E.g. if HoudahGeo is set to display timestamp using the GMT timezone, timestamps will appear to be 7 hours off. Yet they are actually correct.
Now, there is one exception to statement number 1. Some photos - e.g. previously geocoded ones - may contain time zone information. By default this takes precedence over settings made in HoudahGeo.
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