The Micro Four Thirds Lens Correction Project

Although most Micro Four Thirds (MFT) lenses are tiny,  the cameras produce great JPG files with apparently little or no geometric distortion. They do this by applying corrections in camera,  and the correction parameter data is also stored with the RAW file. Unfortunately this data is only useful if you can read it,  and most RAW processors can’t.

Although there’s no obvious reason why not,  Panasonic and Olympus have not published the specification for this data.  That leaves those of us who want to use a RAW processor other than LightRoom or SilkyPix struggling to get decent results with our MFT images.

Building on some excellent work done by “Matze”  ( Raphael Rigo ( I decided to have a go at implementing a parser in my CAQuest plug-in for Bibble/AfterShotPro. However although getting the raw data is fairly straightforward I have discovered that the algorithm is more complex than we thought,  and seems to vary from lens to lens.

I have therefore decided to open up the exercise to a “crowd-sourcing” model to try and get several eyes on the problem. As we uncover algorithms which work well for one lens or another I’ll publish them here,  and also build them into CAQuest.  Over time we may come to completely understand the complete MFT algorithm,  and our work will then be done.  Of course,  if one of the MFT partners wants to help by publishing the algorithm,  that would also be perfectly acceptable :).

The project pages are here:, with a discussion hosted at the Corel AfterShotPro forum.

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