PTGui-thread

[Jochum]

Guess it is more PTGui-users here than on PTGui's own forum, more action here at least. I'm relative new to PTGui, however I have hard time to get good stitch when adding the top zenit picture, shot with Sigma 8mm, though many control points I have hard time, though, I know the zenit shot is maybe not that very good aligned around the nodal point as the row but I get big stitch error, don't think a few centimeters could do that much, doesn't see any parallalex issue between the pictures, so what's up? Do you all here get good stitch easily with zenit shot? Or do you have some great tips that I have maybe missed?

[discocandy]

Jochum.
Could you please give me your setup and workflow?

Do you use normal ptgui or ptgui pro??

My guess still is your no parralax point is not right (as you already tell in your post) but first I want to know your workflow and setup.

[Jochum]

Hi DC!
Didn't know it was that much difference between the versions, but I have the usual cheaper nonpro version.
Why I dont think it is parralex issue is because I can't see in the pictures any big difference, it's like the lense is five cm wrong shooting the zenit (I simply lift of the camera from the tripodhead and place it above turning the lense up so it is like five cm higher from the nodal point) but the churchceiling in this cases are five or more meters away with no extruded parts or arches (more than a few cm), and the stitching error are much larger than the small difference of viewing angle. However it could be the explanation though if no one comes with a good tip.

This is my workflow, load the six row pictures around and the seventh zenit picture, crop, align, sometimes try to move the pictures in Panorama Editor (doesnt know if that really helps), Optimize (with Heavy + lense shift), add extra Control Points in the bad regions and take away bad points, when render it gets not good stich whatever I choose PTgui or PanoramaTools stitcher, Enblend blender gives a slight different stitch but not better. ...It looks like PTGui can't stretch the zenit pictures enough to make it fit to the rest that stitch perfectly. It is where the zenit picture meets the rest there the issue comes.

But is it only me that have problem with the zenit picture? Is that the case the explanation could very well be the parallex issue I have.


Edit: I read now that the Heavy + lense shift setting was not such good idea of me, have tried the others, thought this would be better, later I shall try again without it.

[Adele]

Hi,
I`m using a sigma 8mm on a EOS 5D MkII (fullframe) So I take 3 120° or 4 90° shots with +3° tilt on the NPP-adapter and a freehand nadirshot. Caused to the +3° tilt i do not need a zenith shot.
There is no problem for me stitching in PTgui.
Here is a typycal 4 90° without nadir, the small spot is retouched in PS.
http://www.dd-panos.de/index.php?id=58&pano=56&type=fl
If I know a little bit more about your workflow, I`m sure I can help little bit.

rgds Adele
www.insight360.de

[discocandy]

Jochum.
you could send me the pictures to see??

Do you use a 10mm or 8mm lens??

like adele Says.. is about my workflow with my 8mm but I do 10 degrees up :)

discocandyproductions@hotmail.com

Ps,above is also my msn :)

[Jochum]

What I've seen so far is of my old shots where I luckily shot one or two degree up and a zenit photo is that a churchceiling as an example gets much sharper if I include the zenit shot than without (though harder to stitch), my 8mm Sigma is not as sharp outwards the edges as in the middle.
However if I like you would shoot 10° up and instead a nadir photo maybe it is just as good...?
However I have hundred old panos where I shot 0° up (and many without zenit) so I must find a way.
Wonder, is the 3° or 10° up and a nadir shot the most common way? Thought my way was the most common... :)


(my god how many stones in that celtic ringwall Adele!! :D)

[discocandy]

there are also people who take it 10 degrees downward.
because the floor gets sharper ;)
as you said, the outside of the 8mm is not as sharp as the middle.
but most of the time the top is less important. except when the ceiling is painted like in a church.. :)

I asked the same question on the panotools forum a while ago.
if doing the 10 degree down or 10 degree up is the right way..

Well both are ok depends for what you want to shoot.
there are various way of doing this:

1.render in ptgui without the zenith picture.
Render the zenith apart 100x100 degrees rectiliniar(flat)and load both in photoshop..Use super cubic (http://www.superrune.com/technical/software_supercubic.php) inside photoshop. to get the zenith and Nadir.
just need a little bit of extra distorsion to get it in.

2. Use viewpoint correction (http://www.ptgui.com/examples/vptutorial.html) inside ptgui pro.:D also works very good! well worth the money..

[allSaints]

I also have the Sigma 8mm and I always shot my six images around pointing 15° downwards. And I always set all my control points manually, in the region where I want the stitches to be.

Because the position of the entry pupil of this lens varies with the angle from the optical axis, it is very important that the stitches end up at the same angle that you have calibrated your setup with.

Then I optimize with all horizontal images before I add the zenith image - which is usually no problem at all. It's the nadir image that can be somewhat troublesome. But I have refined my technic, so lately even that one is being stitched pretty easily.

I always choose Photoshop layered file as output, and then I do all the masking by hand. I have never got a satisfactory result by letting PTGui generate a blended file.

I use Nodal Ninja 3 MKII on a Manfrotto 190.

Tommy

[Jochum]

1.render in ptgui without the zenith picture.
Render the zenith apart 100x100 degrees rectiliniar(flat)and load both in photoshop..Use super cubic (http://www.superrune.com/technical/software_supercubic.php) inside photoshop. to get the zenith and Nadir.
just need a little bit of extra distorsion to get it in.

Thanks, shall try that first thing, if i understand it. The Supercubic thing though does not support MacOS unluckily (though it looked complicated).
(I made a file to send to you but I wait a little, want to test your tips first)

[Jochum]

Because the position of the entry pupil of this lens varies with the angle from the optical axis, it is very important that the stitches end up at the same angle that you have calibrated your setup with.

Hej Tommy!
I didn't understand the last part about let the stitch end up at the same angle, can you take it again a little more thorough? Or in plain swedish... :)

[Jochum]

I keep on trying, though it is very much work to stretch and shrink the zenit shot to fit the rest and then mask, dont know if I want to do that on every pano, I've done that enough before when I stitched my old panos manually (though with no zenit).
For fun I through my pictures into AutopanoPro testversion and though it was slower it was much more accurate, less faults and minor faults, not perfect stitch but significant better. But expensiver, dont want to buy that too. If I knew this before I would reconsider. Though I tested both programs with zenit pictures too and then I must have got better result than now, so maybe I have introduced something bad.
But I keep on trying, have some more playcards to test.

Still don't know what that "let the stitch end up with same angle" means, what end up, where? :)

[Jochum]

I also have the Sigma 8mm and I always shot my six images around pointing 15° downwards. And I always set all my control points manually, in the region where I want the stitches to be.

This makes me wonder, I have added many control points where the errors are but the stitcher doesnt obey at all, it keeps on stitch the same fault as before and doesnt want to obey my order, it's strange, it's likes he think he make it better than me, or just he can't stretch the picture enough...
If I make things in Panorama Edit or change anchor image it yield bigger changes.

[allSaints]

This makes me wonder, I have added many control points where the errors are but the stitcher doesnt obey at all, it keeps on stitch the same fault as before and doesnt want to obey my order, it's strange, it's likes he think he make it better than me, or just he can't stretch the picture enough...

Well, that's why I always generate a Photoshop layered file. Then I can put the stiches exactly where I want them to be. And in some places it's better with a knife sharp stich and in another you want a wide gradual merging.


What I meant to say about the pano head setup was:

You try to set up your pano head so that the camera rotates around the entry pupil of the lens - right?
The problem is that with this lens (and most fisheye lenses, I think) there is no such exact point. It varies with the distance from the optical axis (straight ahead). So you can only get a perfect setup for one angle at a time. In your case it should be around +-30° as you use 6 images around.

Regards,
Tommy

[discocandy]

Jochem autopanopro is most of the times worse then PTGUI. Ptgui is really a top notch program.
When you provide the PTS file to Joost,
The maker of ptgui maybe he can help you with ths one. but really most of my panoramas stitch straight away.. sometimes really sometimes i have a minor problem but then i just give some few hand made controlpoints and it works.


Even so.
My workflow is so good I just only need to load it into ptgui.
attach a template and render.. almost no controlpoints needed. but that is only when you are really secure with your setup.
but like Tommy is saying that only works with a fixed lens. my lens is almost always on infinity and take the pictures 100 iso on F8

I really would give it a try myself just to see your problem. can you make a screenprint or even a small panorama you can show??

[Jochum]

Thanks both!
Just send you DC a big email with my sourcepictures, shall be very interesting to see if you have better luck, or skill. :)

[discocandy]

thnx Jochum.
tried it. and this (http://fieldofview.com/flickr/?page=photos/56266685@N00/3386743547&tags=equirectangular) is what I managed to do in 15 minutes, including photoshop work. exluded rendertime :) In a normal version of ptgui..
(shockwave needed)
still some error.. but had not much time (did it at work ;))
I will try it in ptgui pro at home in a few hours :)

[Jochum]

thnx Jochum.
tried it. and this (http://fieldofview.com/flickr/?page=photos/56266685@N00/3386743547&tags=equirectangular) is what I managed to do in 15 minutes, including photoshop work. exluded rendertime :) In a normal version of ptgui..
(shockwave needed)

Now I will try it in ptgui pro.

Great fun to see! You succeeded much better than me, I see some trouble areas same I have but yours are better there, and every of those green arches you made much better! Better than my Autopano test also.
Did you stitch with the zenit picture though?

Now, what do you do that I don't do??! :D

Do you mind to send me your .pts file so I could look what settings you have used?

[discocandy]

Hi. jochem.
no this one was not stitched with the zenith. It was rendered seperatly and added to my psd i als had some work doing this right.
and yes there are still big problems.
My guess is that with the normal ptgui this cannot be done.
As I see the render and the zenith picuture I see you moved for the zenith.
And only with viewpont correction it can be done I hope..

rendering the new image as we speak.. did not test it yet but My guess is that it will be better than the first :)

[discocandy]

this one (http://fieldofview.com/flickr/?page=photos/56266685@N00/3388299198&tags=equirectangular)
Is made with ptgui pro.
rendered as layered PSD. and really needed some work to get it right.
about 30 minutes photoshop work.
A really troublesome picture this is.
even with viewpoint correction and hand set control points it was a real pain in the ...:)

[Jochum]

Yes, there is parallex issue with the zenith picture, its most visible with the strings with golden balls that the candelabra hangs with, however the paintings longer away are no parallexphenomen with what I can see but of course when the zenith picture is taken from a little other angle it will be harder for the stitch software to make it fit, guess that must be it.
Also pondered if I have to much overlap, sometimes that could be a problem.

Now I just get tired of this pano I worked with almost all week so I did like you rendered without the zenit, that works almost splendid, and a second version with the zenit, and then I shall make the rectilinear zenit square with the help of Hans Nygren's tool (what could we call it?) and in photoshop paste in the sharper zenit picture there just around the most central top point, easier to paste it in there than to try to correct the zenith picture in the equirectangular picture. So it will be.
But thanks very very much for your help and support DC, very appreciated!


However ponder now on how I shall shoot churchpaintings the best way from now, 10° upwards and one nadir instead, is that the ultimate, though photograph the nadir is more difficult with long exposures, can't hang the camera from the roof... any idea on this?

Edit: This was written during your last post, shall look into it now.

Edit2: Hans Nygren's "tool" I meant this jewel: http://flashpanoramas.com/forum/showpost.php?p=11914&postcount=15

[Jochum]

this one (http://fieldofview.com/flickr/?page=photos/56266685@N00/3388299198&tags=equirectangular)
Is made with ptgui pro.
rendered as layered PSD. and really needed some work to get it right.
about 30 minutes photoshop work.
A really troublesome picture this is.
even with viewpoint correction and hand set control points it was a real pain in the ...:)
Good work! Very sharp in zenit (and everywhere) indeed. See some problems that just needs some more retouching, yes a heck of a pain, many small figures and patterns everywhere, and on top of that my bad alignment of the zenit photo. But with viewpoint correction you almost got there, but that is at a premium for me (mean it is over my skill and I doesnt have the pro version either so)
Well thank you for everything again, you can't get paid but maybe I can repay someday somehow, great it exist so many friends willing to help out there (or here)!

Regards Jochum!

[discocandy]

I made a small tutorial on various ways I do my nadir.. specially for long exposures.
found here (http://www.flickr.com/groups/nodalninja/discuss/72157613489147281/)
jochem.
Feel free to download the image form my flickr site for your own work.
when you did I'll delete this image because it is yours anyway :)

[Jochum]

Great stuff Freddy! I have horizontal pole possibility on my tripod so I could do that. Though quite cumbersome, it is much work to rebuild the tripod. So my old way is no good longer (a 0° row around and one zenit up)? It would be much easier to work that way, though harder to stitch, but is not that a limitation of PTGui? (wonder how Hans Nygren shoot?) Or is my problem just only because my bad alignment (parallex) so I could stay with my old setup I'm used to if I only fix better zenits?
:)
Don't want your otherwise excellent picture, must make it myself even if I cant make it as good as you did, just the way I am. :D But thanks again for your kindly support and hard work. Cheers!

[allSaints]

Very interesting Freddy,

I use the same technic for my nadir images - using the horizontal pole.

I have only one tripod, so I take the horizontal images with the lower extension part of the legs not extended. And for the nadir image I remove the NN3 panohead, extend the legs of the tripod and mount a plate on the horizontal pole that places the nodal point at exactly the same height as before. It works really good.

I'm sorry I don't have any pics.

Regards,
Tommy

[Jochum]

That sounds slight cumbersome Tommy. The easiest way speaking photographing for me would be to do as I always done, a row around 0° simply and IF inside a building like a church I add the zenit shot to get sharpness up, this is easiest what I can see speaking the photographing. Optional take the nadir shot from the side if it is something worth see there.
However, if I now become better aligning the zenit picture will it still be hard for me to stitch this in PTGui? Is this, the lack of PTGui if it is or if it is just me, the reason many of you instead tilt the camera and do the more cumbersome nadirshot instead? I can't sort this out why not you everyone do the easier way as I do, then I must do something wrong I think..? :D

[allSaints]

Well, nowadays I always take both the zenith and the nadir shot. And I don't have PTGui Pro, so I have to take the nadir image from above. If you have enough light you might do it handheld, but if you need a long exposure, this technic works really well for me...

Tommy

[Jochum]

Never got enough light inside small dark churches. :)

BTW, I had to try something different, I rendered my bad pano first without the zenith, and then I aligned with the zenit sourcepict and crossed only the zenit so I got one pano with slight blurry ceiling and one with only the sharp ceiling and no bottom.
Then I started a very new PTGui project and loaded this two pictures, cropped ceilingpicture so only the uppmost half was left, changed the Lens focal length to 1555mm (just something very long) and the Panorama Settings the projection to rectilinear flat and aligned and rendered and actually I got the best result I have got yet! Some few errors but I think the process could be trimmed a lot and even easier if I render several layers instead.
One bad thing though was the two parts were to the left side misaligned 3-4 pixels and I got a border around everything but it's due I dont know how to stitch just two plain pictures without any focal length or perspective and so on together, this could be trimmed I guess, shall just try to find the thread where it stood how to do that, stitch no photographs, like if I have scanned a big oilpainting or so.

[allSaints]

That sounds really cumbersome, Jochum! :)

[siesfor]

Hey Jochum, if you're going to be taking alot of zenith shots, want to save yourself alot of headache and grief, and don't mind spending a bit of extra dough, then you should definitely think about picking up a spherical pano head like the nodal ninja or one of the others available. Once you've set the head to the right nodal point and locked it in, all you have to do is "set it & forget it". Take your pics, load 'em into ptgui, optimize, and create, without the frustration of misaligned points. You wouldn't think a few centimeters one way or another would cause such problems but they surely do. There's plenty of panos out there made from hand held shots that look fantastic, I don't know how many shots they used, or how much work it took to align them, but I know that until I finally got the ninja perfectly aligned, I would end up with alot of parallax problems w/ the zenith. A hair this way, a hair that way and a mess of problems would creep in, but a perfectly aligned spherical pano head would allow you to create panos with such ease.

[Jochum]

Yes, thanks for the advice. Can say it is not many centimeters that differs when taking the zenit shot with my partly homemade panohead, like perhaps max two cm, however as you say it maybe are too much of distance in this world. I shall definitely consider a nodal ninja, however I was planning to buy a new camera but maybe the ninja is a better investment, too bad our currency drop (Swedish) and making electronic more expensive at same time one want to save on the money...

Siesfor how are you taking your shots, 10° tilt and one down or my way?


Yes Tommy but my very cumbersome method I hope can help with my old already taken panos, taken before I know how to do (then I didn't use the zenit at all but sometimes I took it anyway in case of). :D

[Jochum]

Hi again. The method I wrote last about to stitch with no perspective, like mosaic or partial scans from a scanner is here:
http://www.ptgui.com/support.html#6_6

I tested it on my bad panorama and I must say I got excellent result! Some minor issues to fix though but that's you have to count with. I have yet tested it with only one pano but more are to come I guess. Now I'm not sure I really need a ninja any more... :D Ah, of course now its like stitching two panos instead of one, but it can be done!

[siesfor]

About 10-15 degrees down (enough to just see the edge of the rotator base, creating as small a nadir hole as possible) then flipping the camera up 90 degrees for a zenith.

with the ninja it makes more sense to do it this way since the camera doesn't have to be dismounted, leaving a small enough nadir that it can either be patched in, capped over, or blocked out w/ the limits plugin, assuming there's nothing special about the floor directly beneath.

[Jochum]

Thanx siesfor! :)

[Jochum]

Hi again. The method I wrote last about to stitch with no perspective, like mosaic or partial scans from a scanner is here:
http://www.ptgui.com/support.html#6_6

I tested it on my bad panorama and I must say I got excellent result! Some minor issues to fix though but that's you have to count with. I have yet tested it with only one pano but more are to come I guess. Now I'm not sure I really need a ninja any more... :D Ah, of course now its like stitching two panos instead of one, but it can be done!

Feel I must warn all, don't try this, I haven't succeeded when trying again, it is very cumbersome to mask when the seems are not good stitched, buy a Ninja instead, much better, this is not reliable.

[Nate]

Maybe you all can help me. I've been using ptgui for years (version 7.2). I've been shooting with a canon rebel xti and a sigma 8mm. I shoot six around and one up. I just upgraded to the canon 5d mkII and I shoot the same sequences. With the rebel, ptgui stitches them all day without a single error. With the 5d, I get really strange images... I know my alignment is right, what gives? Please help :) Thanks!

[HansNyberg]

Maybe you all can help me. I've been using ptgui for years (version 7.2). I've been shooting with a canon rebel xti and a sigma 8mm. I shoot six around and one up. I just upgraded to the canon 5d mkII and I shoot the same sequences. With the rebel, ptgui stitches them all day without a single error. With the 5d, I get really strange images... I know my alignment is right, what gives? Please help :) Thanks!

If you still shoot 6 around + zenith I really understand you have problems.

Even with the Rebel you should not shoot more than 4 around.
With the 5D you shoot 3 around.
With 6 around you get controlpoints between for example No 1 and 3 and that can confuse the optimizer.

Hans

[allSaints]

Hmm... with my Canon and Sigma 8mm, I managed to get much better-stiching panos when I went from 5 pictures around to six....

Tommy

[Jochum]

I use six with that setup to use the sharper middle of the pictures and that stitch easily in PTGui, though I, as you seen in this thread get problem when trying to adding a zenit shot, maybe due nodalpoint misalignement though. They does not overlap, 1 and 3 I mean. But that is with my Rebel. So follow what Hans wrote and skip every second sourcepicture and test.

[Nate]

Thanks for the input. I tried Hans method and it came out okay, just not as sharp as I'm used to. I downloaded the newest version trial, and it stitched perfect out of the box. Hmmm. The crop page was already perfect on the new version, where as the older version I have to manually set the crop. I know that my nodal point is correct... Any other ideas?

[HansNyberg]

I see you use an old PTGui 7,2.

The newer versions are very much improved. New improved controlpoint generator and a much improved blender. And dozens of new functions. Like the auto crop.

Regarding sharpness I hope you understand that your new 21mp 5D will make a smaller resolution than your old 10mp Rebel from the Sigma 8mm.
You should get an 8000x4000 with the Rebel and around 7400x3700 with the 5D.

You need another lens to fully use your 5D.

Hans

[Nate]

Right on the resolution. So, is the upgrade worth it? I tried updating to the last 7.x version, but apparently your upgrade is only good for 1 year, not one main version. That's pretty bad business for customers. What lens upgrade would you recommend?
Thanks for the help...

[discocandy]

The upgrade is So worth it.. specially the pro version!
Fusion output is beautiful!
viewpoint correction is great!
And updates for only one year a bad thing?
I think it is fully understandable.
He is working his but off to make this program better and better.:D
And you need to buy upgrades for other programs aswell right?? I need to upgrade to CS4 to use raw images from my 50D :(
On your 5d I probably og for a nice 15mm, or the new 14mm f2.8L:o

[Trausti Hraunfjord]

And you need to buy upgrades for other programs aswell right?

No. Not FPP, not FFC.

.... except in case of complete rewriting.

37 updates... no extra money out of the customer's pockets.

[Nate]

I don't know, I just feel that if you buy a product, you should get the updates for that version. Paying for a new version is okay. I bought PTGUI 7 and I can't even upgrade to version 7.9 because I didn't do it in that first year. I don't mind paying to get version 8, but why not allow me to get all of version 7? Tuddi's got it right.

[sandy]

...I didn't understand the last part about let the stitch end up at the same angle... :)

I take 4 photos to make a pano with my Sigma 8mm fisheye lens giving me 90 degreees between shots, in other words I rotate the lens 90 degrees between each shot. There is a specific nodal point in the lens for a 90 angle. The challenge is finding that specific nodal point. I found the following site that explains how to find it (and for any other angle you might be interested in). It also explains the optical theory of why the nodal point in a fisheye lens changes with different angles between photos. This was a revelation to me. Using this method I found the nodal point for my personal lens to be 13.5mm behind the front of the glass for a 90 degree angle. I used this dimension in my setup and WOW, my photos now stitched up (using Realviz Stitcher) with no ghosting, finally. Give it a try, I bet it helps you nail that nodal point. And thank you to the author of the site for sharing your method with us.

http://thomas-schwenger.de/index.php?ch=kh&sub=sub_tt&pg=npe

Good luck!

[Jochum]

Thank you Sandy. Ah, though the nodalpoint issue I'm familair with, is it that he means with "end up at same angle", okej, it was so easy... :) Thanx anyway. Cheers!

[HansNyberg]

Unfortunately it is not as simple as this.
The NPP also changes vertically so you can still not get a perfect match.

See explanation here
http://www.panoramas.dk/panorama/fisheye-NPP/parallax-blendingpoint.html

and here
http://www.panoramas.dk/panorama/fisheye-NPP/parallax.html

Hans

[discocandy]

Hi Hans.
thnx. for your wonderfull website.
I always look at your page first when I search or an explonation of things.



Personally I created some templates in ptgui and use those as a startingpoint.
After you find a good middle in your nnp settings Ptgui can do most of the correcting. 90 to 99% is always spot on, and just very little work is needed.

Here (http://fieldofview.com/flickr/?page=photos/56266685@N00/3468435725&tags=equirectangular) is a panorama I took pretty fast at a carshow. (shockwave panorama)

stitched started in 30 seconds after loading the images.
only some small error at the top I did not do anything about yet.
and an ugly nadir patch I still need to correct.. but like I said it was a quick one...

[Jochum]

Personally the few I've stitched yet I haven't use templates and it stitch beautifully in a few minutes with almost no errors at all, that of course without the my faulty zenit picture, but so long very good anyway. No need of layers with masks or something. Seems I don't have so much NPP vertical misalignement in my Sigma.

[sandy]

...The NPP also changes vertically so you can still not get a perfect match.



Aha, thanks for the insight -- more science to digest. If I move my camera position in and out to adjust for least vertical parallax then I am also affecting the position set to cancel horizontal parallax. So, what I hear you saying is that once I have my horizontal NPP position set there is nothing I can do to nullify vertical parallax in a circular fisheye lens and must therefore use software to adjust for it.

BTW, I don't have a Nodal Ninja but checked out its configuration on their website -- looks like a very nice piece of equipment. If one is using a 180 degree circular fisheye lens and a camara that has its tripod socket lined up with the center of the lens mount, I see no reason to use the upper rail at all, right? It seems one could mount their camera on the lower rail in the landscape orientation with the body pointing towards the rotation point.

[Jochum]

For the last question it is because it makes it easier to take the zenit picture. If you want sharpness there using the center of lense, like a painted church ceiling for an example. But if you dont use the upper rail I think its pretty much no needed, you can take a bar of anything to attach the camera off to get the right nodal point position.
(btw I dont use the ninja, but I have recently improved my homemade version, will show it when times come for it)

[HansNyberg]

Aha, thanks for the insight -- more science to digest. If I move my camera position in and out to adjust for least vertical parallax then I am also affecting the position set to cancel horizontal parallax. So, what I hear you saying is that once I have my horizontal NPP position set there is nothing I can do to nullify vertical parallax in a circular fisheye lens and must therefore use software to adjust for it.

BTW, I don't have a Nodal Ninja but checked out its configuration on their website -- looks like a very nice piece of equipment. If one is using a 180 degree circular fisheye lens and a camara that has its tripod socket lined up with the center of the lens mount, I see no reason to use the upper rail at all, right? It seems one could mount their camera on the lower rail in the landscape orientation with the body pointing towards the rotation point.

You can not use any software to adjust for parallax. Parallax can not be removed if it is there. What you can do is make sure that if you have subjects close to you you should try to keep them at the center of your image so that you do not need to blend 2 images at that place.
Also make sure that when you stitch your images the controlpoints are not on subject at front which have parallax.

Remember that you get less parallax in the blending area with less images.
There is an very common misunderstanding that you get better stitching with more images and more overlap.
What you may get is more auto controlpoints generated but they will also cover a larger area which are different in parallax.
If you take 6 images and adjust the entrance pupil for the horizont it is obvious that there is larger parallax at the nadir and zenith than if you adjust the entrance pupil for 4 images at 90 degrees.
And especially at zenith and nadir the parallax will give stitching errors also at flat areas.
One of the reasons why IPIX could stitch 2 images together quite easy is that you can get a perfect entrance pupil along the full blending area.

The easiest and best stitching is done with a fullframe fisheye taking 6 around + 1 zenith. PTGui always generates enough controlpoints for this especially if you take your zenith at +70 degrees. And the entrance pupil will not give you any problem as the difference in angle will be very small.

Hans

[Jochum]

+70°? Typo?

[HansNyberg]

+70°? Typo?

No, already at +70 you have the full coverage of the zenith with a fullframe fisheye.
And even if you are at the top of a mountain you will still not have just sky but you have the horizont in the image for controlpoints.
Full coverage vertically is 140 degrees = 70+70 degrees with a 15mm on a full frame camera.
With the 10,5mm on a Canon APS you have 130 degrees and you need min +70 to give full coverage all the way round. You will almost get the horizont in the image.

Hans

[Jochum]

Ah, see, sounded peculiar first. :)