Fix Eye Level

Can I somehow fix the eye level in post?
I captured a talking head video and I used an external monitor slightly lower than the camera lens so the speaker does not seem to look directly to the camera but slighty lower.

Not really. The 3-dimensionality of a face would point to any fake correction by tilting a two-dimensional picture.

Our human perception is very sensitive to recognising where someone is looking so unless you can replace the eyes with CGI it can’t be fixed. Generally it’s very hard to get anyone but a trained actor to talk directly to camera without using some kind of autoque. Adding distance between the camera and sitter helps as the angular difference is reduced.

I worked on a huge, major, big-budget network awards show about 20 years ago where the producers realized during the edit that the camera was a little too low, which made the host of the show look a little old and "jowly." We were asked if we could change the perspective a little higher in post; we could not.

They frantically ran out a day before the show aired, rebuilt the set and reshot all the host's speeches without an audience in about 90 minutes, at a cost of about $50,000. This time, the camera angle was raised slightly to provide a more flattering angle to the host, who looked a lot better. Those new shots were dropped into the show, which aired the next night... and nobody was the wiser.

So, no: there's no way to change perspective, particularly up & down (north & south). There are new multi-sensor camera systems out there, like Lytro and Raytrix, which shoot from a dozen or more angles simultaneously, and you can change the shot in post in three dimensions. But they're costly, complex, and require a lot of planning. It's almost always a lot more practical to just get it right on the day.

So true!