Using a Canon 10D (Old school, I know), a Manfrotto 303SPH and a Sigma 10-20mm f4 lens. I have been shooting at 60 degree intervals - two rows at 30 degrees (1 up 1 down), one shot straight up and a handheld bottom, so 14 shots total.
 
This lens is technically not a fisheye, but it's got a good bit of distortion and Stitcher Unlimited seems unable to finish a calibration. It hits 69% and hangs for a bit, then goes to 75% and craps out with an "unable to calibrate" message.  
 
I got a good tripod and found my entrance pupil/pivot point/nodal entrance point. It seems to pass my visual parallax tests regarding the spacial relationship between two objects at various distances.
 
So, with all that in mind, I have been going nuts trying to get rid of ghosting. I have been using Photoshop to edit it out, but that's not great for many reasons.
 
Anyone have any experience with this lens and Stitcher? It seems like a decent lens so i am blaming the inability to calibrate since it's the only thing that's left at this point. I suppose the entry pupil/pivot point could be wrong, but it really doesn't seem like it.
 
Thanks in advance.
 
 
 

try using stitchers Smart Blend option when rendering, it can be a big help in dealing wit ghosting issues -

Thanks, Sam. I'll give that a go. Also, i tried doing three rows of shots at 45, 0 and -45 and that helped immensely. i am trying to wrap my head around the relationship between the angles and the way Stitcher deals with stitching. It seems like 90's and 45's have a more "parallel" stitch as opposed to an "angular" one, if that makes sense.  
 
A cubic VR I shot with the exact same as above setup produced no visible ghosting when I changed angles. I'll try the smart blend as I'd rather knock these out in two rows.
 
Thanks for the response.