a HDRI of just the..ceiling

[3dmonkeydude]

Could you shoot a HDRI of just the..ceiling..?
The sky…like
A 180 …from a fish eye lenses and
how would you map it ….
to work in a environment map


Also does anyone know of a. way to stich 2 fish eyes together...

[Dschaga]

this tutorial is somehow outdated, but still the right way IMHO:
http://www.cgtechniques.com/tutorials/hdrenviroment.php

2 fisheye to one sphere is -> Ipix
it's a patent of ipix ... the sad point is that ipix sues everyone who is using this technique:
http://vr.albury.net.au/%7Ekathyw/EyePics/ipix.html

(btw, it's no problem to use a special dll from the panotools and a short script to automate the task of stitching two fisheys together)