I have been playing around with pftrack tring to get a good solution for a specific shot.
It has a good amount of motion and camera blur but has quite alot of tracking points so should not be very hard to track.
However I have had quite a big problem with it and it will play in slowmotion so the tracking needs to be perfect.
The shot was filmed with a RED ONE in 120 fps and 2048×1024 resolution.
It starts of with tilt that goes into a pan and ends with another tilt.
During both tilts there is a quite large amount of lens blur and the pan is hard to track in its self.
One question I am uncertain about is the input of focal length and film back.
What numbers are used and why?
I found this link that has some great information:
http://www.jfi.net/RED/REDFormats3.pdf
Following that I use
Frame aspect: 2
Principal point: 49 and 49
Filmback: 11.0592 and 5.5296 (mm)
Pixel aspect: 1
Focal length: Variable
What I am unsertain of is:
Principal point, what is it and is 49×49 correct for me?
Film back: Are those numbers correct?
Focal length:
I am a noob when it comes to photography so bare with me on this one.
If we didnt use the zoom and just used the focus. Does that mean that the focal length is constant?
Specificaly for pftrack what length does it want? Because by looking at the graphical representation to the right in the camera parameters window it seems like it is the total lenght of the lens AND the camera distance to the film back.
Is there anything else that need to be corrected since we only used a part of the sensor or is that included in the numbers from the pdf?
Thanx guys!
dew
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