[Erasmus]

If this video was taken by WFAA, the photo of the camera iris does not show the kind of iris in use.

In a professional camera, the iris is a diaphragm contained within the lens, and is composed of several (at least 5) blades, which maintain a near circular aperture under all settings.

[Alberta's Child]

The video was attributed to WFAA, but from what I can gather it was taken by a member of their staff with a personal camcorder while at home or on the way to an assignment.

Let's also consider something very obvious here -- if you were out looking up at the sky with a camcorder, and you were filming the space shuttle hurtling sideways through the air in a doomed re-entry, would you zoom out so that you could no longer see the object in detail?