On 17 Sep 2003 at 14:48, Lon Williamson wrote: > Apparently, any lens-body combo has an axis about > which it can be panned that minimizes distortion for > reconstituting panoramas. I think "nodal point" is part > of the technical discussion. > This is a thing I've read about and couldn't grasp. > And, more to the point, see how to test and implement.
The nodal point of a lens can be tested easily if you have a mount which allows easy adjustment of the sidewards and front to back position of the camera relative to the centre of rotation. Crossed macro slide rails are excellent however you only need one macro-rail (for front to back adjustment) if the tripod mounting point is directly under the axis of the lens mount. Testing for the nodal point of a given lens is a relatively simple task. The procedure is to set two coincident objects at one side of the finder view at a few metres distance apart. If the lens is set at the nodal point the two objects will remain aligned as the assembly is panned to the other side of the finder. Whereas if the lens is rotating in front of or behind the actual nodal point the objects will appear to have moved sidewards relative to each other as the lens will have actually shifted horizontally. Rob Studdert HURSTVILLE AUSTRALIA Tel +61-2-9554-4110 UTC(GMT) +10 Hours [EMAIL PROTECTED] http://members.ozemail.com.au/~distudio/publications/ Pentax user since 1986, PDMLer since 1998
