Field of view in the Oculus VR

User Pogo on the Oculus VR forums asked the other day about why some applications didn't cover more of the available screen real estate on the Rift, and consequently occupied a smaller field of view than was possible.

Every pixel on the Rift display has a fixed relationship with the lenses (discounting the slight differences between the three sets of lenses that come with the Rift).  Each pixel has a specific θ (pronounced theta) which represents the angle between the lens axis and the line from the pixel through your eye.  Each pixel also has a specific 'perceived θ', which is the perceived angle between the lens axis and the where it appears to be because of the lens distortion.  

What this means is that if you're drawing on a smaller area of the Rift screen, you're essentially providing a smaller field of view.  

As an example of the issue Pogo posted the following images.  The first is from the Oculus configuration utility used to test the IPD and height settings a user has entered.

The second is from the lauded RedFrame environment demo.

And the last is from Half Life 2.  

All three applications are using native Rift support, but are rendering different fields of view.  But why?  Well, there are a number of reasons that this might happen.

The Challenges of Adapting Cinematography to VR

There was a question today on the Oculus VR Developer Forums about cut scenes in video games and how to approach them in VR.  Essentially, the original poster was asking how to address the conflict between cut scenes, which typically follow the language of cinema, offering frequent cuts from one point of view to another, and VR where 'cuts' can be disorienting to the viewer.

Here's my response, only lightly edited:

This is an interesting topic and is part of understanding the intersection of VR and cinematography as a whole. Part of cinematography is the manipulation of the frame, the field of view, the depth of field, the lighting, etc in order to convey an emotion or idea.

However, the language of cinema doesn't necessarily translate 1:1 to VR. Sudden transition of the viewpoint in film, or 'cuts' are so common in that it's considered notable when you go for long periods without them. But as you say, they can be extremely disconcerting when done in VR, where you've increased the level of immersion specifically to make the viewer feel more like they're present in the scene than simply a viewer. This means that common things like the 'Angle / Reverse Angle' sequences used to alternate between closeups of two people speaking as they converse is something that doesn't really work in VR.

The problem is, how do you convey certain non-verbal ideas without saying them. Cinema itself had this very problem, because it was a medium that grew out of the effect of disruptive technology on a prior storytelling medium, the stage, which in turn had to deal with the same problems.