3.4 No-Parallax Point
What is the No-Parallax Point?
Rotating the camera on the No-Parallax Point (also referred to as Nodal Point) results in no parallax between foreground and background. To avoid errors in the panorama stitching process we need parallax-free images, which we’ll only get when rotating on the No-Parallax Point
The exact location of the No-Parallax Point varies from lens to lens
For our Canon EF 8-15mm fisheye, the No-Parallax Point is close to the entry point of the lens, approximately at the first black ring
Finding the No-Parallax Point
The concept
Align viewfinder’s center with tripod’s center of rotation
Align No-Parallax Point of lens with tripod’s center of rotation
The way to adjust the axes will vary for each panorama head model
Enable viewfinder’s center
Enable the Grid Display for the viewfinder
Align with the tripod’s center
Point the camera downwards and adjust the 2 axis on the panorama head, so that the viewfinder’s center cross matches the tripod’s center of rotation
Rotate around the center and check the entire 360˚
Find 2 vertical lines
Level the camera. Find 2 vertical lines, one very close, one further away. You can use tripods, lamp poles, door frames, window blinds etc.
Camera centering overlapping lines
Position camera that the 2 lines are in the image center and overlapping perfectly
Rotate and monitor shift
Pan to the side and monitor if the 2 lines are shifting towards the edge of the frame. Rotate in both directions
The lines in the example have shifted slightly: There’s parallax and we’re not on the No-Parallax Point yet
Adjust millimeter by millimeter
Adjust camera position to align No-Parallax Point to tripod’s center. For Nodal Ninja: That’s the lens-ring connecting to the head
Adjust, rotate and monitor until no shift
If the lines are still drifting apart, return to adjusting millimeter by millimeter and repeat till they’re not shifting anymore
You have found the No-Parallax Point when both lines are overlapping perfectly while rotating in both directions
If the lines are not shifting: Congrats, ready to shoot