I've a full 360 panorama created with ICE and uploaded to Photosynth. When zoom out the perspective is nice and straight. But when I export to HDView (not the SL version) all straight lines display more curvy at equivalent zoom level. Also there appear a
convergence seam at both nadir and zenith. Is this a normal behavior of hdmake/HDView? Is there any parameters that can make it match those of photosynth output?
HDView lets you zoom out to a full 360 degree field of view. To allow this it starts warping the perspective projection to a latitude/longitude projection once the field of view increases beyond a certain angle. So what you're probably seeing
is that Photosynth maintains the pure perspective projection for wider angles than HDView does. Unfortunately the parameters controlling this behavior in HDView aren't user settable.