Why is IMAX not wide screen?

[NL197]

As part of the "Focus Points" featurettes on The Dark Knight BD, there is mention of not utilizing the top of the IMAX frame as much because a person's field of vision isn't naturally that high so it's mostly dead space. That certainly played a key factor in modifying the image to 1.78 for Blu-ray.

Where you sit in an IMAX theater is really where you can tell if it's more immersive or not, because if you sit too close to get a 'bigger' image, you'll be looking all over the place to keep up with the action and that can be very distracting.

Personally, I've always sat at the very top of the theater I've been to, because it allows for looking straight across, and downward without having to miss anything.