fixing distortion for tracking

#1

first, i do not know if this is the right place to ask this since i cannot find any place specifically for this.

my question is:
is it better to fix the distortion in comp then exporting the footage to track in PFtrack,boujou,sytheyes?

OR

fixing the distortion in PFtrack then have the tracking software export it for use in comp later on?

i havent touched this bit so much since the director wants the distortions sometimes and may be pissed off when the framing changes so slightly.

can i export the footage to have the CG elements distorted to match the distortion on the footage later on at comp as well?

any help will be appreciated! thanks thanks thanks

#2

The basic workflow is…

[ul]
[li]Shoot a checkerboard which each lens you use on the film.[/li][li]Using the checkerboard footage, undistort the footage and save them out to a new image sequence. You typically do this once for each lens. You can either do this is comp (Nuke) or in the matchmoving software (PFTrack) - it depends what you feel gives you the best results.[/li][li]Write down the info used to undistort the footage - most big studios store lens distortion data in a database, you could use a spreadsheet to write it down (ie… 50mm, undistort amount = 1.2).[/li][li]Track the footage. If using PFTrack to undistort the footage, make note of any info about that distortion.[/li][li]Render the CG elements.[/li][li]In comp apply a distortion node to the rendered CG elements. The distortion should be the inverse of that used to undistort the filmed footage - then composite the CG with the original filmed footage.[/li][/ul]One thing to make sure of is that if your letting the matchmoving software deal with the undistortion is that you can apply a matching distortion in comp.

#3

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