Hi Chris, It's just that some cameras (Nikons in particular) treat the lowest ASA setting to be an "extended" mode, which isn't recorded in the Exif header in the usual fashion. If this ASA is 50, setting the ASA to 100 usually solves the problem. If the lowest settable ASA is 100, try setting it to 200. (The same is true for the opposite end of the sensitivity scale, but you should stay away from this for HDR captures.)
The ASA is generally fixed in an exposure bracketed sequence, or should be. Some cameras offer an "Auto ASA" mode, but you should definitely avoid this setting for HDR. For the purposes of putting the ASA back into the equation when it was not recorded, you can often use the camera itself in one of its information modes to tell you what it was actually set to when you took the exposures. Does this help? -Greg P.S. To keep the subject line the same and enable thread-tracking, be sure to respond to the posting and not the digest. Easy to forget. ;-) > From: Christian Humann <[email protected]> > Date: April 21, 2012 7:41:45 PM PDT > > Hi Greg and Axel, > > Thank you so much for your input. Both methods seem to work although I'm > still a bit confused on the ASA setting. > > Greg, in your comment: >> Usually the only information missing is the ASA, and this can usually be >> solved by choosing an ASA that is 1 EV higher. > > Do you have an example you might be able to offer that I can work from? I'm > not sure how to work out an ASA from an exposure value. Would the ASA value > change with each bracketed exposure? I'm still scratching my brain cells > around some of this and am not sure yet how to interrupt sensor sensitivity > from these Machine Video cameras and the various settings the interface > allows one to control. > > Thanks again! > > Cheers, > Chris
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