At the half of my shot (constantly moving camera) there is a focal length change. In my first tests the camera is moving forward instead of zooming into the scene. Is there a trick to automatically detect the focal length change?

Is it currently possible to reconstruct the camera from such a shot at all? Until now I only have found this proposal, but I could not figure out if this is part of blender.


Sadly, this is not possible in Blender. There are other pieces of software which can do what you wan't:

Some of these are a little expensive, but they are all far superior to Blender's tracker in many ways. Note: Mocha is the best matchmoving/roto/cleanup tool out their. by far. (No affiliation, promise), PFtrack also is very good at what it does, but it is still a point tracker.

  • 1
    $\begingroup$ add also PFMatchit and PFTrack Both are capable of tracking shots with variable focal length. $\endgroup$ – cegaton Nov 20 '14 at 2:40
  • $\begingroup$ @cegaton I was looking for PFTrack but failed to find it. It costs as much as a (well) used car though. But the object tracking is to DIE for $\endgroup$ – GiantCowFilms Nov 20 '14 at 5:48
  • $\begingroup$ @GiantCowFilms - Thanks! How do you know that? Just your experience? Can you add a reference, paper or wiki-link why this is not possible in blender? $\endgroup$ – p2or Nov 20 '14 at 11:19
  • $\begingroup$ @cegaton - Thanks! If blender really fails to solve this shot and especially in terms of reconstructing the camera, pftrack is one of the best options for sure. $\endgroup$ – p2or Nov 20 '14 at 11:27
  • $\begingroup$ @poor I know experts (who have worked on open movies) and such who have tried and failed to do what your asking. $\endgroup$ – GiantCowFilms Nov 20 '14 at 15:24

the gsoc 2013 proposal you linked to doesn't seem to be included in blender master/trunk yet, so you won't find it's features in the latest version.

You can use a special build from the GsoC 2013 motion track branch though. http://graphicall.org/1063

  • $\begingroup$ Thanks guest! I've tested the build, sadly with no success. There is a new "constrain focal length" checkbox as part of the refine settings. With this you can enter a min and max value of focal length, but when I setup my values it has no effect and the camera is still moving forward like in the current build. $\endgroup$ – p2or Nov 18 '14 at 16:46

Your Answer

By clicking “Post Your Answer”, you agree to our terms of service, privacy policy and cookie policy

Not the answer you're looking for? Browse other questions tagged or ask your own question.