Pro video blog…Produced by Philip Johnston DoP/Editor

This was brought to my attention over the last two days. If you are filming with your GH4 and you get a power failure the file you were recording turns into an unusable .mdt file. I saw this online and decided to record an experiment myself. What you see is from my SDXC card recorded tonight. During recording I deliberately removed the battery and caused a corrupt file. We are no strangers to this phenomenon at HD Warrior as that was why the “Z” test was invented. The Sony MC50 was an early adopter of corrupt files if it had a hint of power failure but I am surprised that we are still getting this 5 years later.

“A file with the MDT file extension is a Microsoft Access Add-in Data file, used by Access and its add-ins for storing relevant data.

Although Microsoft Access uses both file types, an MDT file shouldn’t be confused with the MDB format that Access uses to store database information, unless your particular MDT file happens to be an old Microsoft Access 97 template file.”

This is a good reason to record important one off filming like a children’s event, onto an external recorder. Will the GH5 suffer this problem, we can only wait to see if the designers have included some form of buffer between the media and the camera.


Having been working in the video business since 1988 I have amassed a great amount of knowledge of both the kit and production values over the last 30 years.

2 thoughts on “When your GH4 file turns to toast…when you see a .mdt file

  1. That’s weird. GH3 doesn’t have that issue.

    HDW : Never had a GH3 but thanks for the info.

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