Nodal points for canon lenses

[panoramaone]

Does anyone have a list of the nodal points for canon lenses for panoramic photography. Oh and the sigma 15-30mm lens.

Cheers I know it is about halfway but I want to be more accurate than that and I dont want to test all my lenses if I can help it.

 

[fredlord]

Does anyone have a list of the nodal points for canon lenses for
panoramic photography. Oh and the sigma 15-30mm lens.

Cheers I know it is about halfway but I want to be more
accurate than that and I dont want to test all my lenses if I can
help it.

Sorry:

No way. They have no list that you'll have access to. They aren't very often halfway. The only way to find them is the hard way like the rest of us found them. Oh, and they are different for each focal length on the zoom lenses. I can tell you that after hours of my own testing.

Cheers and good testing.

 

[Jason Hutchinson]

Most likely, you don't want to use the nodal point for panoramic photography. You want to use the front entrace pupil. Are you sure you want the nodal point?

Jason

Does anyone have a list of the nodal points for canon lenses for
panoramic photography. Oh and the sigma 15-30mm lens.

Cheers I know it is about halfway but I want to be more
accurate than that and I dont want to test all my lenses if I can
help it.

 

[panoramaone]

The literature that I have come across mentions nodal point, the point where the light crosses over.

Jason

Does anyone have a list of the nodal points for canon lenses for
panoramic photography. Oh and the sigma 15-30mm lens.

Cheers I know it is about halfway but I want to be more
accurate than that and I dont want to test all my lenses if I can
help it.

 

[panoramaone]

Fred: If you have some of the distances for your lenses please post them. I am sure that others would like to know the proper distances you have for your lenses.

Darcy

Sorry:

No way. They have no list that you'll have access to. They aren't
very often halfway. The only way to find them is the hard way like
the rest of us found them. Oh, and they are different for each
focal length on the zoom lenses. I can tell you that after hours of
my own testing.

Cheers and good testing.

 

[Ed Halley]

Most likely, you don't want to use the nodal point for panoramic
photography. You want to use the front entrace pupil. Are you
sure you want the nodal point?

The nodal point is the place where all light rays cross through a single point, and rotating the camera around that point between two successive shots will have no parallax alignment problems.

As stated above, it depends on the focal length, which means that zoom lenses will move the nodal point as the zoom is moved. To be truly accurate, even two copies of the same prime lens should be calibrated separately.

The proper calibration of your lens' nodal points is critical for indoor or "macro panos." If you're taking wide landscapes, and nothing distinctive is within about 50 feet, the issue is far less critical.

--
[ e d @ h a l l e y . c c ] http://www.halley.cc/pix/

 

[Jason Hutchinson]

I've read that's a myth, here's some text I grabbed from the way I understand it:

"* with a conventional camera (ie not a rotary panoramic camera), when you shoot multiple pictures that will be stitched into a panoramic view, you have to rotate around an axis crossing the entrance pupil center, not the front nodal point [of course when there are only distant objects in the frame, this is quite needless]. See for example the "Lens FAQ" by David Jacobson. This topic has also been discussed at great length with Emmanuel Bigler on the French site http://www.galerie-photo.org (search "Point nodal" in the upper frame when it is loaded). Remark : in symmetrical lenses the entrance pupil won't be at the center of the lens, because the aperture stop is at the center of the lens and the entrance pupil is the (virtual) image of the stop made by the front lenses.

• In a rotary panoramic camera, the lens rotates around its rear nodal point because this makes the image almost stationary (so there is no blur when the "light slit", which has a finite width, goes across the film). In return for which, the "point of view" will change across the image, because the center of the entrance pupil will move (unless it coincides with the rear nodal point). This is not a problem because no stitching is needed. "

This was taken from:
http://www.photo.net/bboard/q-and-a-fetch-msg?msg_id=003bju

 

[Richard Fisher]

Can you help me understand what a nodal point is and how you would use it?

Thanks,

Rich

Does anyone have a list of the nodal points for canon lenses for
panoramic photography. Oh and the sigma 15-30mm lens.

Cheers I know it is about halfway but I want to be more
accurate than that and I dont want to test all my lenses if I can
help it.

 

[Jason Hutchinson]

Here's another claim that using the nodal point is a myth. This one is from a more familiar source:

http://www.vanwalree.com/optics/misconceptions.html#6

"Many sources that write this don't specify whether it is the front or rear nodal point, but either way it is incorrect. To preserve the perspective during rotation, which prevents a displacement of nearby objects relative to the background, the axis of rotation should pass through the entrance pupil, which is the center of perspective of a lens. No doubt instructions to find the position of the rotation axis will lead to the correct point, it's just that the designation nodal point is wrong. The good news is that, unlike a nodal point, the entrance pupil can be found by visual inspection. When you look into a lens from the front, the entrance pupil is the image of the diaphragm opening. "

Jason

Does anyone have a list of the nodal points for canon lenses for
panoramic photography. Oh and the sigma 15-30mm lens.

Cheers I know it is about halfway but I want to be more
accurate than that and I dont want to test all my lenses if I can
help it.

 

[Dr. Eric A. Durant]

I wish that I had a proper panoramic head so that I could test this more methodically, but I just did a few tests with my Canon 28-135 at various focal lengths across the entire zoom range. I had a slatted chair back about 1 foot in front of the camera, and a wall with details about 20 feet away so that I could easily observe parallax. Rotating the camera/lens system about the tripod mount caused obvious parallax, while rotating the system about the front lens element caused very little or no parallax. Some parallax was noticeable at intermediate points. All rotation axes were vertical, of course. Don't take my word for it, though -- try it for yourself. Doing this with a panoramic head could help eliminate many of the sources of error, but I did my best with the equipment I have.

Of course, it matters less and less when the nearest object in your panorama is sufficiently far, but it is interesting to put the lens within a few to several feet of foreground objects sometimes, where parallax can be significant. I've had mixed results with this have been considering a panoramic head with all the proper adjustments for that reason.

Best Regards,

Eric

 

[panoramaone]

When you look into a lens from the front, the entrance

pupil is the image of the diaphragm opening. "

Jason

That's good info, I don't have a lens with me at the moment, but by looking through the front of the lens and seeing the diaphragm opening can we guage where that would end up at the side of the lens.? And would that mean that the "rotation point" will always be the same on a zoom lens?

 

[Dr. Eric A. Durant]

When you look into a lens from the front, the entrance
pupil is the image of the diaphragm opening. "

That's good info, I don't have a lens with me at the moment, but by
looking through the front of the lens and seeing the diaphragm
opening can we guage where that would end up at the side of the
lens.?

That's how I understand it.

And would that mean that the "rotation point" will always be
the same on a zoom lens?

No, the specifics will depend upon the lens, but this tends to vary a lot with zoom amount and slightly to moderately with focus setting.

 

[fredlord]

Go here:
http://www.kaidan.com/nodalpoint.html

It's not a myth. It certainly makes a lot of difference in my panorama stitching accuracy. Follow the instructions for each and every lens and each desired focal length and you'll have it. I can't do it for you. I will say it gets harder for wide-angle focal lengths (below 28mm). Telephotos are a cinch.

Good luck

 

[panoramaone]

Excellent article. Thanks Fred. That will help and it looks quick and easy.

Darcy

Go here:
http://www.kaidan.com/nodalpoint.html

It's not a myth. It certainly makes a lot of difference in my
panorama stitching accuracy. Follow the instructions for each and
every lens and each desired focal length and you'll have it. I
can't do it for you. I will say it gets harder for wide-angle
focal lengths (below 28mm). Telephotos are a cinch.

Good luck

 

[Jason Hutchinson]

Go here:
http://www.kaidan.com/nodalpoint.html

It's not a myth. It certainly makes a lot of difference in my
panorama stitching accuracy.

Yes, that method works but it's not finding the nodal point. It's finding the front entrance pupil. You need to look through my link above.

Jason

 

[Jason Hutchinson]

Please see this FAQ by Jacobson himself, question 20:

http://www.photo.net/learn/optics/lensFAQ

*****
Q20. For panoramic pictures, where is the best place to pivot the
camera?

A. The axis of the pivot should pass through the entrance pupil. The
entrance pupil is the virtual image of the aperture as seen through
the front of the lens.

When you've got it right, the entrance pupil will not shift relative
to fixed objects as you rotate the camera. (Stop down the lens so you
can see the diaphragm and aperture.)

There is a whole different type of panoramic camera in which the lens
is rotated relative to the film. In this type of camera the lens
rotates around the rear nodal point (for objects at infinity). See
the lens tutorial for an explanation of nodal points.

*****

Go here:
http://www.kaidan.com/nodalpoint.html

It's not a myth. It certainly makes a lot of difference in my
panorama stitching accuracy. Follow the instructions for each and
every lens and each desired focal length and you'll have it. I
can't do it for you. I will say it gets harder for wide-angle
focal lengths (below 28mm). Telephotos are a cinch.

Good luck

 

[panoramaone]

Hi Jason:

Yeah, I read the information you gave earlier and believed it, I am just happy to get ta technique to find the magic point, no matter what it is called. But yes I believe it is the entrance pupil. Thanks for your help and your response also. It is very helpful also.

Cheers,

Darcy

http://www.photo.net/learn/optics/lensFAQ

*****
Q20. For panoramic pictures, where is the best place to pivot the
camera?

A. The axis of the pivot should pass through the entrance pupil. The
entrance pupil is the virtual image of the aperture as seen through
the front of the lens.

When you've got it right, the entrance pupil will not shift relative
to fixed objects as you rotate the camera. (Stop down the lens so you
can see the diaphragm and aperture.)

There is a whole different type of panoramic camera in which the lens
is rotated relative to the film. In this type of camera the lens
rotates around the rear nodal point (for objects at infinity). See
the lens tutorial for an explanation of nodal points.

*****

Go here:
http://www.kaidan.com/nodalpoint.html

It's not a myth. It certainly makes a lot of difference in my
panorama stitching accuracy. Follow the instructions for each and
every lens and each desired focal length and you'll have it. I
can't do it for you. I will say it gets harder for wide-angle
focal lengths (below 28mm). Telephotos are a cinch.

Good luck

 

[Don L]

I've always thought these were the same. At a very small apeture opening those light rays better cross over at about the same place as the diaphram opening.
--
Don L

 

[fredlord]

Yes, that method works but it's not finding the nodal point.

Note: You may call it what you wish. The first four words in YOUR sentence are the relevant ones.

 

[Dr. Eric A. Durant]

Jason -- thanks for posting the detailed, informed, and relevant references. This has concerned me for some time with my own panoramic photography -- both which methods work to (efficiently) control parallax and what the correct terminology is.

Best Regards,

Eric