About the NODAL POINT! Panorama Photography.

[Kodiak]

•
To find the nodal point of a lens is quite easy to do, but accuracy is critical.
I am assuming here that you are using a panorama head on tripod and that
the camera is levelled… all these points are critical!

One needs two vertical objects as reference points, like a street lamp post
at some distance and a studio light stand, or a broom or hockey stick closer
to the camera.

Here are the 3 possible situations:

In this image, one can see the unwanted results of been over the nodal
point. You will have to fiddle, a bit plus a tad os less, to get to the right
place on the scale.

•••••••••••••
In this image, one can see the unwanted results of been under the nodal
point. Again, you will have to fiddle, a bit plus a tad os less, to get to
the right place on the scale.

•••••••••••••

Here you can see what you are aiming for. It doesn't matter which is
afar or closer. All that counts is that, from on end of the frame to the
other, the distance between the 2 reference objects remains constant.

Once you found the right setting on the scale of your pan-head,
TAKE GOOD NOTE OF IT! This spot will apply to that specific camera/lens
focal length combination. If you don't take note of it, you will have to do
it again next time around.

Have a good time fiddling! :-)

At no extra charge, here is the gear I'm using for my panorama works:

[Manfred M]

Good explanation Kodiak.

From a practical standpoint I use a vertical point in the distance (edge of a wall, for instance) as one of the points and the tip of the spud from one of my C-stands as the second of two targets to do this alignment. I have a chart of common lens / focal distances taped to the bottom of my nodal plate so these dimensions are always handy.

Your setup is a lot more complex and robust than mine (I adjust only along the axis the lens); but then, you do this type of work for a living...

[Glenn NK]

Very well done and illustrated Daniel.

Because I use a TS lens, it's not necessary to know the nodal point. BUT, just shifting left/centre/right won't work either. If the lens is shifted 10 mm to the left on the camera, the camera/lens combination must be moved 10 mm to the right. In order to slide the camera/lens, I have a quick release clamp that is marked in mm so sliding the camera/lens is quite simple.

If one does not either rotate the camera/lens about the lens nodal point or use the shift technique, parallax errors will result and the stitch will be more difficult (messy).

Glenn

[Kodiak]

Good explanation Kodiak.

Thanks Manfred… I was so afraid to be obscure and too complicated!

Your setup is a lot more complex and robust than mine (I adjust only along the axis the lens); but then, you do this type of work for a living...

Tools are tools. My pride is not in the tools but in the way they permit a
good living for the boys and me.

•••

An exemple of 360° interior panorama:

Should you be interested, I could post others.

[Kodiak]

Very well done and illustrated…

Thanks Glenn, but I can't take credit for the illustrations which are from a very
cool dude at the Melbourne university… down under!

[ST1]

Interesting and clearly written process Kodiak, thanks for taking the time to produce this.

Would you mind describing the individual pieces of kit that makes up your gear in your images. I do recognise some of them but...not all of it:-

1. A Manfrotto L Bracket
2. L Bracket attached to a focus rail (the rail giving fore/aft and left to right adjustment)
3. But...what is it, sitting below 2 above and the tripod is that the panorama head ?

Also is the lens shown a tilt and shift version.

[Manfred M]

Thanks Manfred… I was so afraid to be obscure and too complicated!



Tools are tools. My pride is not in the tools but in the way they permit a
good living for the boys and me.

•••

An exemple of 360° interior panorama:

Should you be interested, I could post others.

And a very nice interior pano. I have been looking to do one of a ruin in Gatineau Park, but every time I got there, it is crawling with other people and I haven't managed to get it yet. As for an interior; that hadn't occurred to me; but then; why not?

[Kodiak]

Interesting and clearly written process Kodiak, thanks for taking the time to produce this.

Thanks Peter.

Would you mind describing the individual pieces of kit that makes up your gear in your images. I do recognise some of them but...not all of it:-

All Manfrotto… hard to beat: (click these links)
Levelling Base
Panoramic Rotation Unit
VIRTUAL REALITY & PAN PRO HEAD

Also is the lens shown a tilt and shift version.

I have two Nikkor PC lenses: the 24/ƒ2,8 and the 85ƒ2,8. The one seen above is the 24.

I also have a robot to produce very large panos on 12 rows and 60 columns (and more)
but at this point, only medium to large corporations can afford these.

[Polar01]

I have a question or two about doing the setup for nodal points. I process is fairly simple yet takes time, no problem there, now the two main lens I wish to do this to are my 16-35mm and 70-300mm nikkor. I have a flag pole about 75m from my house, I use that as the far point, the near point is say 2m away will these distances work for both lens or do I need to change the working distances closer with the 16-35mm lens.

Cheers: Allan

[Kodiak]

…will these distances work for both lens or …

No, these distances will work for none!!!!!!!!! In theory yes but in practice…
most questionable. Let's establish some basic understanding:

The nodal point may be determined for any lens but think about DoF… Your
flag pole is at 73m from the 2m closer object. Since most will use a wide
angle lens for panos, imagine how good one can see a flag pole at 75 m
from a wide angle lens… thin as a thread or even less!

For wide-angle lenses, set up and vertical something at… 1m is ok for the
closer object, for the further away thing let's go for a broom stick at 2m to
3m and you'll be good. The distance does not have to be great but clear.
The object closer to the lens should not be too big as to eclipse the other
one… you will not be able to continue if it would be so.

Do I somehow answer the question?

[Polar01]

Thanks that is what I thought, looking at video's and such they never give a good ball park distance they just show the principal behind the method. Now on Tuesday I can setup and get my nodal points as I love doing panos, have not been able to get any help from members of our camera club as I am the one, most ask for help with their pans.

Thanks: Allan

[Inkanyezi]

I don't know if there's any point in trying to change the rather loose terminology of photographers to that of optical engineering. The point we are looking for is the centre of the entrance pupil of the lens, while nodal points (in optical engineering) is something else.
http://en.wikipedia.org/wiki/Cardina...9#Nodal_points

In a way though, using the entrance pupil could simplify setting up for a pano, as setting this point can be done by looking at the lens from front while turning the pano head, or just estimating its virtual position binocularly. When the entrance pupil does not move when the camera is turned, you have found what photographers call the nodal point, or what maybe correctly could be called "no parallax point", i.e. the entrance pupil position. In most short focal length lenses, the entrance pupil, as seen from front, is very close to, or the same as, the virtual position of the diaphragm. John Houghton explains it at his site. http://www.johnhpanos.com/epcalib.htm
Don't miss looking at more of his page, with tutorials and images. http://www.johnhpanos.com/

Using the method with two objects, where one wants to find a point where there's no parallax when the camera is turned, the close object could be rather close, and the far object needs not be very far away, and it helps if both are reasonably sharp. It might be easiest to use a setup where the DOF covers both objects, not spacing them unnecessarily much. Precision is highest when you have them close to the camera.

[loosecanon]

When I got my pano bits I found it cheaper to buy the individual parts of Manfrotto kit rather than as the nice boxed kit. I find the sliding plates they sell for video cameras smaller, lighter and quicker to adjust than the macro plates you use. The L bracket now sold is very good with the adjustments it has, just £90 a little pricey.

I use a 20mm or 35mm prime (depending on sensor size). Too wide a lens and the perspective advantage of a pano over super wide angle lens is lost.

[TonyW]

I was going to question the terminology but Urban beat me to it.

I have another question too. To what extent does the no parallax point depend on the current focal length of a zoom lens and on the distance of focus?

[Manfred M]

To what extent does the no parallax point depend on the current focal length of a zoom lens and on the distance of focus?

This seems to be somewhat dependent on the lens design. I mainly shoot the internally focusing Nikons and here the centre elements are shifted, rather than having a stationary centre and the front element moving. Well over 1 cm in some of the testing I did, depending on the lens and the focal length that was used. The 14-24mm shifted the least (almost negligible) and the 70-200mm shifted the most.

I haven't tested any of the more traditional zoom lenses, so can't comment there. The primes don't shift at all.

[Rita]

Kodiak, thanks for posting your explanation. It is helpful.

[george013]

Here is a database of different camera's and lenses to give you an idea. http://wiki.panotools.org/Entrance_Pupil_Database.
A macro-slider might be enough, but only in landscape and for camera's with the tripodconnection on the optical ax.
George

[IzzieK]

+1 to Rita's comment...I have been doing pano on the cheap--handheld -- so I think it is about time I learn to use my tripod for doing so.

[Kodiak]

[QUOTE=Glenn NK;443715]Because I use a TS lens, it's not necessary to know the nodal point.QUOTE]

The quest for the "nodal point" is relevant and a must when one needs to
pivot (on a vertical axis passing through the said "nodal point") any lens…
even all TS lenses if they are to be used on wide panos because then the
PC or TS lenses are used like normal lenses.

In a fixed horizontal or vertical axis, this "nodal point" is irrelevant for all lenses

[William W]

. . . I can't take credit for the illustrations which are from a very
cool dude at the Melbourne university… down under!

Thank you for now choosing to reveal that information.

WW