Camera-matching Sigma 8mm fisheye

[jackbird]

I'm trying to match the output from a Sigma 8mm fisheye on a Canon EOS 7D within max/vray.

The fisheye camera (in the render options dialog) appears to capture significantly more than a 180 degree arc - put a camera dead-center in a sliced sphere, and the output will contain background color in a circle around the sphere. Adjusting the parameters does not seem to affect this.

More effective appears to be using a VRayPhysCam with an 8 mm lens/36mm gate and quadratic distortion set to 0.8125.

I need some justification for such an arbitrary-seeming setting though, as later down the pipeline this footage is going to get unwrapped to an interactive pano. Has anyone suffered through this workflow before and can give some advice?

[chriserskine]

the 7d isn't a full-frame camera so won't be 36mm film gate, unless you multiply the 8mm x 1.6.
camera info is here
http://www.dpreview.com/products/canon/slrs/canon_eos7d

I'm assuming this is from a 360 pano and are you planning to match it before stiching all the photos together?

fisheye has a different type of distortion, have you tried using camera overide to set as a fisheye lens?

the other option would be to stitch the pano together then match that with a equirectangular (sphereical) projection.

third option would be to remove the fisheye distortion before both matching and stitching photos. and then you should be able to match to a standard lens.

I'm not sure what option there are for this camera lens for undistorting the image. I know with the nikon 10.5mm fisheye there is a one click option to remove it in nikon capture.

[jackbird]

it's not a 360 pano, it's roughly a 180 pano from a single shot with the Sigma lens (no stitching. This rig is used to shoot 1080 video which is then viewed in an interactive player as a 180 pano video.)

My goal is to perspective-match the output of the camera - no stitching, unwrapping, or rewrapping required. I need to deliver distorted, fisheye-looking frames to my client.

[chriserskine]

I'm still on vray 1.5 so i haven't tried this.

have a look at the vray lens analysis utility.
http://www.spot3d.com/vray/help/200R1/tools_lens.htm

looks like you will need access to the camera though.