Frame judder

Et objekt bevæger sig over skærmen men det “flicker”. Why?

Fænomenet hedder “judder”.

“Although judder has many contributing factors, it is ultimately determined by how fast a scene moves from one side of the screen to the other. The rule of thumb is to pan no faster than a full image width every seven seconds, otherwise judder will become too detrimental. This rule is especially simple and powerful because it applies regardless of camera lens, model or sensor size.”

– RED101

“The eye is capable of seeing the individual frames when there is very fast motion present with an insufficient frame rate. Conversely if you had an animation of a very slow moving small object you might be able to get away with a very low frame rate before any judder is noticed.

One can help alleviate judder with motion blur…..However these solutions are never going to work as effectively as what Dave suggested – increasing the frame rate or reducing the speed of your animated motion.

-Graham Macfarlane, Creative Cow

The seven second rule:

For any object crossing the width of the frame,it should take 7 seconds or more to be smooth

Det kan både være i en optagelse eller i en AE animation.

Her er lidt info om panning speed og judder med klassisk kameraer.
En konkret tabel fra ASC manualen –

/Volumes/Stock Footage/Tutorials/ASC_-_American_Cinematographer_Manual.pdf

og en artikel fra RED:

Post produktion:
Motionblur kan skjule meget.
Framerates er nøglen så hvis der overhovedet er mulighed for at ændre frameraten til f.eks 50 frames kan det hjælpe.
Hvis der er tale om motiongraphics kan det hjælpe problemet at animere i hele frames dvs 1,2,3 og ikke 1.1,1.2, 1.3
Der findes scripts som kan hjælpe.

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