Hi Jeremy,
your approach of determining the focus position and temperature coefficient for different filters is essentially OK. And yes, there is a way to get and evaluate the data with less effort: simply use Mikael’s ‘SGP Auto Focus LogViewer’, see SGP AutoFocus LogViewer SGP AutoFocus LogViewer . The download URL is SGP AutoFocus LogViewer download | SourceForge.net .
This application extracts and evaluates the AF data in logfiles of SGP.
Bernd