Board index Photography Technical Questions Finding the nodal point and Panoramic Head

Technical Questions

Finding the nodal point and Panoramic Head

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a_zeitler
 
Posts: 458

Finding the nodal point and Panoramic Head

Post Tue Mar 20, 2007 2:27 am


Hello, I just purchased a Manfrotto 303plus Pano head (mounted on an acratech leveling base) and now I need to learn a way to find the Nodal Point of a lens. I have done some research and came across two different methods.

1) For an 85 1.8 lens the nodal point is 85mm from the "film plane" indication mark. This goes for a 50mm 1.8... it is 50mm from that mark. Has anyone ever heard of this or used it?

2) The second and most common way was simply trial and error. By moving the camera slightly, check the relationship between foreground objects and background objects. When these objects relative position does not change, you are at or near the nodal point. Has anyone ever used this method?

If anyone can please help me out, I seem to be lost at this point. I have been fairly succesful creating panos without the head, but I wound up cropping the center out and spending ALOT of time stitching them together. I want to speed the process up as much as possible and create more consistant results. Thanks for any help.

thazooo
 
Posts: 51


Post Tue Mar 20, 2007 6:49 pm


Here's a link with a lot of info,

http://www.panoguide.com/


I've found it easiest using the trial and error method in regards to 'Nodal' point. For distant scenes it never comes into play, only for close objects in the scene.
if you want to speed up the stitching time and not run yourself crazy :-)
Buy a good pano program, there are several out there, I bought Panorama Factory. Works well in both AUTO and MANUAL stitching. A friends got Ptgui (?) and says it works well also. If you plan on doing several rows and columns stitching, make sure the program supports its.

a_zeitler
 
Posts: 458


Post Tue Mar 20, 2007 8:49 pm


thazooo,

I took a glance at your panorama gallery. Very nice collection. I noticed that they were shot with a 28mm 2.8 lens. Since it is 28mm, is there a problem with distortion? I always learned that a 50mm lens has no distortion at all and is the optimal lens for panoramas. Do you correct the distortion or do they simply stitch together easily and seamlessly?

thazooo
 
Posts: 51


Post Tue Mar 20, 2007 11:22 pm


A Zeitler,
The 28mm stitches flawlessly, on the digi it's close to the 'normal' lens. I've played with my 50mm and it stitches flawlessly as well. I've shot some with my Sigma 17-35 EX, at the wide end I end up having to do a manual stitch which inturn gives some warpage and a smaller crop on output. The closer I get to the 28mm length with the sigma, the less processing is involved.
The program I use does correct for lens distortion.

A Tip, I shoot an image every 15 degrees, this gives a large overlap for the images. So much so that if I run into problems stitching, I can drop a frame and then do a manual stitch to correct the problem. I find that this happens mostly if a moving object is in the scene.

thazooo
 
Posts: 51


Post Tue Mar 20, 2007 11:25 pm


P.S.

Very nice Pano Gallery !!



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