Posted 08 May 2008 - 01:42 PM
I'm new. from the wild yonder. and have medium level English knowledge.
I have in mind improvising a camera rig that alows panning without changing perspective; for that I need to know how far to offset the camera backwards with respect to the lens. and even more, how about when I use a zoomlens.
I'd be greatfull for any reply.
Posted 08 May 2008 - 04:31 PM
Posted 08 May 2008 - 05:11 PM
already did what you suggest. it isn't working. the axis of the movement has to cross some nodal point in the lens. it works the same with still panoramic cameras, where the lens pans by itself around this virtual nodal point, covering the wide angle. the problem is that I don't know the math for that nodal point. it has to be on the axis of the lens, in front of the focal plane, but how far? I imagine it varies with lens. that is why I'm wondering about zoom lens correction. with the tilt, even if I don't need it for now, I know how it's working.
my problem is that I have objects close to the camera, as well as a distant background, and I don't want the these different planes to float, one in front of the other, it has to be static.
Posted 08 May 2008 - 11:33 PM
Please change your user name to your real first and last name as per the forum rules.
Posted 09 May 2008 - 05:03 AM
Posted 09 May 2008 - 06:42 AM
Posted 09 May 2008 - 11:53 PM
The way I was taught to find the nodal point is to place two objects directly in line with the camera both at a set distance apart, so the first object is 1 metre away from the camera and the second object is 2 metres away from the camera. By sliding the camera backwards and forwards along the baseplate (or a rotating base of some sort) pan the camera left and right. If the camera is rear of the nodal point then the first object will stay closer to centre of frame, where if the camera is forward of nodal the rear object will stay closer to the centre of frame. If the camera is nodal then both objects will line up during the pan.
You beat me to it. The trick works beautifully, I have used it to set up DSLR panos before. C-stands work brilliantly.