HDRI creation from full frame fisheye

[walee]

I want to create a hemispherical HDRI, using a full frame fisheye and shooting upward (in this case a sigma 8mm circular fisheye mounted on a canon 5Dmk2) . The resulting image is something similar to a mirror ball that we would have shot from above. My quetion is :

- can we use the resulting image like this, or do we have to "unwrap" the image to another format so that it will be usable by vray ?

Thank you for your help,

[Dschaga]

You will only have the sky but nothing under the horizon.
The fisheye have a different projection characteristic then a mirror ball. I played around with shrink wrap projection (which is a mirror ball projection) and the tiling option, but it isn't a similar projection - you have to convert the image into a spherical projection ..with hdrshop1 or any other software.
About exposures have a look at this : http://projects.ict.usc.edu/graphics/skyprobes/

good luck!

[walee]

thx for the link, it's a really interesting article.

[simmsimaging]

Check Peter Guthrie's blog: he has a tutorial on exactly that IIRC. Either way you can certainly create skydomes for use in Vray with that approach.

b

[walee]

yes Brett, peter gave me the url of his blog, it was pretty useful thanks.