panorama software,virtual tour software
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2006-06-30
#1

Nodal Point Help

Yes, I know, this question again. But I know many of you love challenges and enjoy teaching others.

I have been creating 360 panos since last fall with the following set up- Realviz Stitcher, Canon Digital Rebel with stock lens, and a Kaidan QuickPan system with Spherical Bracket.

However I just got my Sigma 8mm Fisheye this week and I have been playing with it for the past day and a half. I love it and I found Panoweaver to be very easy to use.

I have been doing some experimenting trying to find the nodal point for this lens and I feel I might be missing something. I have create a series of images from several points on my set and they all seem to produce some offsetting of the tripod head stitch. Anyone interested in taking a look and letting me know which setting seems the closest?

The images are at: http://www.uvm.edu/~khytten/nodal_pt/

They start with Testing_63-R1765
And end with Testing_80-R1765

The numbers 63 and 80 correspond to points on my bracket, 65 is forward and 80 is back. The R number is the radius of the circle, I altered that a little because of something I read in another post that Dave did regarding nodal point adjustment. I have looked at Daves nodal info at 360texas and I had tried using the gold ring on the Sigma as the nodal adjustment. It seems the series of images I have taken are slightly ahead of center and back.


Thanks for the help!

--Kevin

--Kevin

http://www.webvisiontours.com/
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2006-07-15
#2
I've spent the better part of this evening setting up the nodal point on my new tripod, head and Nodal Ninja 3.

I think I am close but something seems a bit off. All images shot by leveling the first image only - leveling done via tripod head and hot shoe level.    Suggestions? Here are some nadir shots and links to the source images are here:

http://www.uvm.edu/~khytten/nodal_pt/nn3_nodal/

I thought this first image looked close - but some areas line up and others don't - see how the lower right stitch seems to shift more then others.


Some other tests:




--Kevin

http://www.webvisiontours.com/
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2006-07-16
#3

Kevin,

All look pretty close to the money. If I was to say anything it would still appear to be a little sideways adjustment is needed. But that said, you might just be at the point where things are good enough. Because Panoweaver is an "automatic" stitcher there is only so far you can go with it too achieve perfection. The errors should only be small and a little Photoshop work will fix them up. The alternate is to use manual stitching points to help warp the image into shape. You are always going to have the issue with lower or upper extremities of the image to some small point, not withstanding your "black square" issue because of your camera-lens combination being slightly larger than the camera CMOS sensor and thus the crop circle within Panoweaver 4.0. Shooting the Zenith and Nadir shots and stitching them all in Panoweaver 4.0 should give you the perfect result without (or at least very little) Photoshop clean up.

Regards, Smooth 


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2006-07-05
#4
Hi folks, here is an update. I am getting closer. One thing I noticed is that I am still off on the Zenith but the Nadir looks good. For example, here is my nadir for a sample:



And here is the zenith for the same pano:



The full image is here: Testing_81-102_B.jpg

Here is a similar setting with a 5th zenith shot: Testing_82-102_C_with_Zenith.jpg

Acceptable I guess. Do you think I could do better or am I getting picky?


--Kevin

http://www.webvisiontours.com/
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2006-07-05
#5

Kevin,

Mate you are a lot closer too the money now!

It still does needs to be further adjusted though.

Points that come to mind:

  • How are you leveling the lens? (Is it really level?)
  • Shooting with some things close in some shots and far in others will result in errors. (Not really optimal for setting up) The door frame is close when compared to other shots. The fisheye entrance pupil moves slightly when light source is on objects near and far. Better to keep things at an equal distance - or deal with these small parallax errors in Photoshop.
  • Looks to me by sight that the lens needs to come forward a little on your panohead.
  • Do not re-level in every position (Position (1) needs only to be perfectly level)

Your side to side position nows appears to be correct. Just a little more adjustment forward should do the trick.

Whatever the case you must be a lot happier than you were....

Regards, Smooth


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2006-07-05
#6

Smooth, I agree.  we should be seeing more of a circle spirit level.  Also notice that there is some ziggyness in the wood floor/carpet upper right of pan head.

You know you set up in the MOST difficult location - DOOR WAY.  NO ONE shoots a panorama in an open door way. LOLLLLOLLL . !! 

If you do GET this doorway figured out, and I have no doubt you WILL - we will declare you an INSTANT MASTER and throw Roses at your feet.. and we all will do a community WAVE in your honor.

Well gee whiz folks... here is a small tip for zenith shots. 

I try to always set up 1 to 2 meters offset to the room center.  Then I don't have to deal with room mid center ceiling lights, chandeliers, or overhead cross beams OR OPEN DOOR FRAMES.

Only a thought


/s/
Dave
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2006-07-05
#7
Thanks,

I ordered a quick release plate today, so I hope it will help me once I have things dialed in. I use a Kaidan QuickPan Rotator Base with Spherical Camera Bracket with Universal Camera Mount. It looks sort of like this (this is an older model and mine does not have a quick release plate):

I need to attach the camera to the Universal Camera Mount that slides onto the Spherical arm (left image) each time I set up, that means keeping things on the mark is tricky.

To answer Smooth, I tried leveling the lens today with a small torpedo wood level I had, placing it on the hot shoe edge. The level is plastic and looks something like this:

I know it is not ideal, but it was what I had to work with.   Not a single camera shop in my area carries a hot shoe level. I ordered one today from B&H.

As for the whole setup I do level everything up for the first shot, but not after. So I am doing as you suggest. I picked that up from my Realviz days of taking 38 images.

Why the doorway?   Well I did it on purpose. I took these last test panos in the door way to try and see the stitching better on the zenith, the previous shots had the stitching seams on a white ceiling; I wanted a bit more contrast. However, great advice from Smooth and Dave about setting up shots. Ive done a few panos in which I had cloned out the tripod and it took me a number of poor setups to remember to look up and down when setting up.

I try to avoid shooting into a light above and if I want to clone out the tripod I look for some easy to clone consistent floor or ground. While I am still learning I realize that the best panos dont just come from good equipment and an accurate nodal point, success can be thwarted before you even snap the first shot if you have a lousy position.

Ill keep messing around to share my results.

Dave, Smooth says he thinks the lens needs to come forward a bit, you suggest we should see more of the circle level. Seeing more of the circle level would mean moving the lens back a bit, correct? I did try the setup in both positions, a little more forward and a little more back. Each produced some errors. I might just wait for my hot shoe level and quick release plate to come in before I do too much messing further.

Thanks again!

--Kevin

http://www.webvisiontours.com/
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2006-07-06
#8

Kevin,

To make the spirit bubble level look like it does on the panohead you must move the lens forward. Both Dave and I are saying the same thing. The way it is in your shots shows 4 separate glimpse's of the spirit bubble and a square hole (you shouldn't see this square hole). This hole is also prevalent at the top also. (you will not totally remove the top square but it will be smaller when the camera and lens is set up correctly over the entrance pupil).

Once you add your quick release you will have to set this up all over again (LOL) Still it is the way to go. Your Kaidan set up is very similar to what I once used before switching to Agnos.

That spirit level you have is similar to one I use only bigger mine will happily fit in my pocket and is sized about the same a pen $6.95 AUD from the hardware store. I also use a Hot Shoe twin axis bubble level. I also had trouble finding one locally (in Australia) so I purchased on from the USA via Ebay for about $29.00 USD delivered (Top Investment).

Keep your results coming Kevin we are all interested in seeing it all come together.

Regards, Smooth


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2006-07-06
#9

Hmm just thinking about the 'forward-backward' thing.  I suspect it depends on what side of the camera you are standing. 

Below find a very confusing picture.  Let me explain:

If you move the camera forward you will see less of the pan head center spirit level.

If you tilt the camera lens up you will see less of the pan head center spirit level.

The opposite is true if you want to see more (blue lines) of the pan head center spirit level.

It also follows logically that the same affect is being observed at the zenith top with cieling lights, cross beams, doorways etc.


/s/
Dave
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2006-07-06
#10
Smooth and Dave,

Are you suggesting I move forward or Tilt as Dave explains above with the blue line?

I assume that I am aiming to keep the lens level 100%, such as Daves orange line that goes to the hot shoe level.

I am still playing with settings. It is really amazing how such small movements can affect the image. I enlarged the circle in Easypano a bit more and captured a bit more ceiling space. I will post again soon when I think I have it closer.



Or when I have more questions
--Kevin

http://www.webvisiontours.com/
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2006-07-06
#11

Yes, level, level, level...please do not tilt down or up and

if you move forward (to the left in the photo)  you will see less of your center spirit level. 

All you need to see is 1/2 of it in 1 shot.  If you see half in all 4 images then when stitched all 4 will come togther and form a perfect circle.

Only a thought


/s/
Dave
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