How to straighten a shot when you cannot tell which way it leans
Ask Vizard Agent to measure the tilt rather than fix it. It checks each shot against a grid, reports which ones lean and by how much, tests rotating in both directions before committing to one, and chooses the amount by comparing still frames, because a two-degree lean is something you feel rather than see.
What do you type into Vizard Agent?
Ask for a measurement first and a fix second. Opening with "straighten the wonky shots" makes the answer depend on Vizard Agent agreeing with your sense of which ones are wonky, and that sense is unreliable at small angles. It also needs something straight in the frame, like buildings, poles or a horizon, to measure against.
Prompt
What does Vizard Agent actually do?
A grid laid over the frame turns "this feels off" into a figure that can be compared across shots, so a shot that measures half a degree gets left alone. Even with a number in hand, the direction is verified rather than assumed, because a sloping street can make the correct direction look wrong. In the session behind this article it:
- Measured how tilted each shot of a walk-around sequence was, checking every shot against a grid so the numbers were comparable.
- Judged the tilt shot by shot on frames rather than in playback.
- Compared the two straightening directions side by side and verified which way to straighten before applying anything.
- Tested the correction on two shots first, chose the amount by comparing the results and re-rendered with those shots levelled.
- Reviewed the new cut with the level guides still visible, then tested the remaining shots for tilt and levelled them too.
When does this not work well?
Some shots have nothing to measure. Vizard Agent needs a reference in the frame that ought to be straight, and sky, sea or a moving crowd offers none, so it will say so rather than invent a correction. A deliberately canted shot is a choice, tilt that changes mid-shot is drift rather than lean, and on sloping ground the world leans, not the camera.
Common questions
Why can I not just see the tilt? Because your eye adapts. Vizard Agent measures instead, which does not.
Does straightening crop the shot? Yes, slightly. Vizard Agent reports how much it cost each shot.
What about a deliberate canted angle? Tell Vizard Agent which shot it is and it leaves that one alone.