--- In PanoToolsNG@yahoogroups.com
, Keith Martin <keith@...> wrote:
> Sometime around 6/10/10 (at 11:05 +0200) Michel Thoby said:
> >I believe that you have encountered the fisheye "bulging" problem.
> >It is a direct consequence of the inherent characteristics of the
> >fisheye lenses where the entrance pupil moves when the angle of
> >entering light changes.
> This is also why the perfect head alignment for 6 shots isn't
> necessarily the same as the perfect head alignment for four shots
> with the same lens. The critical area of overlap will be in a
> different part of the shot (okay, slightly), so the effective
> no-parallax-point could be slightly different. We're talking about
> small differences, but it is worth considering.
The problem is that if you adjust for 6 shots / at the centre) you get larger parallax at the + -45 degrees areas which is actually where most people have the problems.
In my opinion adjusting for the number of shots without doing zenith is just wrong.
The blending point will increase all the way up to the zenith and if you shoot 6 you have a very large parallax difference.
Also if you shoot zenith the critical area is where the zenith blends the 4/6 around and that will be at 90 degrees both for zenith and the 4 around but if you shoot 6 you have a mismatch with the 6 around blending at 60 while the zenith blends at 90
You can use the new feature in the editor in PTgui 9 beta to see exactly where you blend.