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Thread: Constant drift - is this fixable with my NN3

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Tom Vogel

Posts: 27
Location: Cambridge, Ontario, Canada
Registered: 5 Mar 2007
Constant drift - is this fixable with my NN3
Posted: 10 May 2008 at 6:28 GMT
Hi all,

I've been struggling with a constant drift in my panos. I use the NN3 / peleng 8mm / canon 400d and PTGui. I shoot 8 + 1 zenith (if I shot 4 + 1 as I know is ideal for my lens ... the drift creates very big problems during the prep to stich).


Here's an example of what I get with almost every freshly stitched Pano:



I've been told that drift can be corrected by tightening the knurl knob on the NN3 - I've done that to the max and it has helped on occasion to create a straighter result (not perfect but passable). Problem is that the knob is so tight that I end up having extreme difficulty turning the panohead on its axis ... on many occassions I end up taking the tripod around with it.

I'm careful to get the bubble spot on in all my first shots. This shot was level looking through the archway into the living room. The bubble drifts throughout the series of shots yet comes back to center when I complete the series. So it's an easy enough fix in PtGui. I'm getting annoyed, however, with having to fiddle with every pano after it's been Aligned in prep for final stiching. I'm also wanting to explore Batch stiching - but this is impossible with such a result.

Is this the end-product of a faulty NN3 rig or is there some detail I'm overlooking?

I look forward to any advise any of you can give.

Thanks!

Tom
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DorinDXN

Posts: 1671
Location: Timisoara, Romania
Registered: 14 Nov 2006
Re: Constant drift - is this fixable with my NN3
Posted: 10 May 2008 at 6:44 GMT
updated: 10 May 2008 at 6:45 GMT
Hi Tom, your NN3 is perfectly fine you only need to level the pano at stitching time or after, see the excellent tutorial by John Houghton here
www.johnhpanos.com/levtut.htm

Dorin
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John Houghton

Posts: 2265
Location: Hitchin, United Kingdom
Registered: 17 Jan 2005
Re: Constant drift - is this fixable with my NN3
Posted: 10 May 2008 at 7:52 GMT
Tom, When your panorama is levelled with t1 points, the top and bottom of the image become straight. This suggests that your pano head was reasonably level and that the cause of your problem is slight roll of the camera. Try optimizing the horizontal images only, with the two link pitch and roll boxes checked and y,p,r for all horizontal images checked. Uncheck the "Use control points of" for any other images. You can then read off the camera roll value on the Image Parameters tab. The panorama image will now have a nice straight top and bottom. This doesn't guarantee that the actual image data will be levelled, as that depends on whether the pano head rotation axis was vertical.

You now need to uncheck the two link boxes and y,p,r on one image - to create an anchor image. Then optimize normally. If the pano head is reasonably level, your verticals will probably be reasonably vertical.

It only takes 40 secs to level the panorama accurately with t1 points, provided there are some verticals to put t1 points on, so I don't think the levelling of the pano head is too important.

John
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Skridlov

Posts: 127
Location: United Kingdom
Registered: 12 Nov 2007
Re: Constant drift - is this fixable with my NN3
Posted: 10 May 2008 at 13:31 GMT
Hi Tom
as a relative beginner I can confirm what wiser contributors suggest here - as they also told me. I have to say that the NN3, which I also have, is a bit of a disappointment in this respect, however post-levelling as described in John's tutorial solves the problem.
Roy
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Smooth

Posts: 1455
Location: Australia
Registered: 21 Jul 2004
Re: Constant drift - is this fixable with my NN3
Posted: 10 May 2008 at 14:17 GMT
updated: 10 May 2008 at 14:22 GMT
It is IMPOSSIBLE with any panohead using a bullseye bubble level for the bubble to stay within the center of the level during a 360 degree rotation. NO panohead can do this, it is not a result of brand X vs brand Y.

Without the aid of a bullseye bubble level the human eye couldn't even see this minimal "drift" as you call it. It takes only minuscule adjustment or movement to have a dramatic effect on such levels.

It is perfectly NORMAL for the bubble to move all over the place, so long as it returns to perfectly level at the 0 degree/position 1 click stop/starting point.

You should ONLY level your panorama head at 0 degrees/position 1/starting point and NOT make any attempt to re-level at any other click stop position.

Leveling the panorama "image" should be done during or after stitching using the T1 control points in PTGui.

Batch stitching requires panohead with repeatable accuracy which just about cancels out any panohead that mounts via the camera body (unless it has some sort of locking device or pin) Lens grip panoheads like the Agnos RingT or BoPhoto heads with an optimized .pts template that has been made from your own individual combination (I.E: Camera, Lens, Panohead) are also required it is NOT just the hardware/panohead that guarantees batch stitching. "IF" that was the case then any images shot with these "so called" batchable panoheads would stitch perfect, first time, everytime with "any" of the stitching software packages without any manual adjustments EVER!

Simply, this is NOT possible and never likely to be. You need a quality panohead with personal optimized software templates to match YOUR equipment.

If you are still thinking the bullseye bubble level should be in the centre (or even think it's possible in a real world environment) when rotating 360 degrees via click stops YOU ARE KIDDING YOURSELF!

It's like trying to stack marbles.

Regards, Smooth cool
www.smooth360.info
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klausesser

Posts: 38
Location: Duesseldorf, Germany
Registered: 18 Feb 2008
Re: Constant drift - is this fixable with my NN3
Posted: 10 May 2008 at 14:44 GMT
updated: 10 May 2008 at 14:47 GMT
Hi Tom!

I agree with what smooth said before!

I don´t know PTGui much - i use AutoPanoPro. Here an option exists which is really georgeous: the "vertical line" tool.
You can draw lines along all the non-verticals in your pano-editor window you want to be exact vertical and hit "enter". APP corrects/undistorts your whole pano perfectly.
The sane you can do with horizontals - if you couldn´t shoot right-angled a wall or so. You draw a line along the non-horizontal part in your picture which you want to be straght horizontal and hit "enter" - and APP corrects your whole pano perspectively.

best, Klaus
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Skridlov

Posts: 127
Location: United Kingdom
Registered: 12 Nov 2007
Re: Constant drift - is this fixable with my NN3
Posted: 10 May 2008 at 14:49 GMT
The NN3 leans like the tower of Pisa with my D200 camera so the position of the bubble's irrelevant anyway! And the yaw axis tensioning system is HOPELESS! Maybe I'm using the wrong coin - maybe it should have an Eagle on it or summat... If it comes to that I find it pretty hard to get the detent click function (on the 60 deg washer) to work smoothly - partly because of the above tensioning deficiency. So I end up aligning the yaw increments by eye.

Also the +/- 90 deg setting is ... interesting. If you align the vertical post and the camera arm so that there is no apparent displacement (ie they are parallel by eye and touch) the bezel markings certainly won't read 90 deg. They won't even read the same on both sides!

The NN3 is light, portable, robust etc but it could be a lot better. No doubt the NN5 is, but that's how it goes with technology, even relatively simple mechanical technology. Whatever we buy is almost instantly improved upon. I just wish I could afford to upgrade stuff the moment an improvement arrives.
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John Houghton

Posts: 2265
Location: Hitchin, United Kingdom
Registered: 17 Jan 2005
Re: Constant drift - is this fixable with my NN3
Posted: 10 May 2008 at 15:06 GMT
While batch stitching is not practical with the NN3 (or even the NN5), it is still worthwhile creating a template, which will make stitching easier. This will set up the lens and image parameters to a fair degree of accuracy. Optimizing with a few control points will then fine tune the alignment to give a good stitch. Don't, however, click the Align Images button after applying a template; it will undo all the good work done by the template.

John
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Smooth

Posts: 1455
Location: Australia
Registered: 21 Jul 2004
Re: Constant drift - is this fixable with my NN3
Posted: 10 May 2008 at 15:13 GMT
Roy,

You are using the older MKI Nodal Ninja 3 I suggest you do a small upgrade and purchase the NEW lower rotator that is vastly improved and allows you to update and improve your NN3 for minimal cost.



See www.nodalninja.com/order_nodal_ninja.html (about half way down) or contact Red Door in your part of the world.

No coin/screwdriver required. Really they are chalk and cheese. HUGE improvement.

Regards, Smooth cool
www.smooth360.info
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Bill Bailey
[NodalNinja]

Posts: 414
Location: Phoenix in the Arizona Desert, United States
Registered: 27 Jan 2005
Re: Constant drift - YES this is fixable with my NN3
Posted: 10 May 2008 at 15:56 GMT

Skridlov said:

Hi Tom
as a relative beginner I can confirm what wiser contributors suggest here - as they also told me. I have to say that the NN3, which I also have, is a bit of a disappointment in this respect, however post-levelling as described in John's tutorial solves the problem.
Roy


I believe both you and Tom have the older versions of NN3's. The older versions do work perfectly well however you need to make sure the lower rotator is "properly" tightened. This will ensure smooth and level rotation.
There is a wrong way and right way to tighten this. Once properly tightened the unit should be both secure and should not wobble or unscrew (although we always recommend turning it in a clockwise manner) here is the procedure:
a) Loosen the knob with "Nodal Ninja 3" marking, next loosen the inner lock screw on the knob. Once the knob is loosened, the silver lock screw is easy to loosen. You can loosen the screw with your finger.

b) Tighten knob until you achieve the desired rotation tension or friction. You can note the amount of friction by holding the base rotator and turning the lower arm around in a "clockwise manner", as this prevents unscrewing of the base unit until locked with inner lock screw. It doesn't take much tightening at all.
c) After the larger NN3 knob is tightened, tighten the inner (silver) lock screw with a screw driver or coin). This "locks" the tension of the rotator knob and it should not unscrew. You might have to do this a couple times to get the proper feel. Double check the tension against the click stop feel and readjust as needed.
If the unit still has a tendency to unscrew try placing an extra Teflon washer (included with each NN) under the rotator knob (with Nodal Ninja markings) and repeat above steps.
Proper tightening should enable the user to find a friction point that you feel comfortable with and ensure you get a good level during 360 rotation.

The new Nodal Ninja 3 MKII has an improved lower rotator that totally eliminates the need for adjusting tension in this manner. Current users of the earlier versions can upgrade for a small nominal cost.



Note on the NN3 bubble level:
The bubble level is extremely sensitive - maybe to much so. It's difficult to obtain a true and exacting level so some bubble drift is likely. As long as the drift isn't excessive you should be able to find a happy medium. Using multiple levels is like stacking marbles and also becomes very difficult and personally I do not recommend this. Stick with one level - preferably the one on the Nodal Ninja.

Also make sure you have a good quality tripod - some tripods have wobbly necks.

Also make sure you don't rest your hand on the camera while rotating the rig. The added weight can very easily through off your level. Rotate the Nodal Ninja by simply placing your fingers or hand gently on the lower rail (outer edge) to turn.

If all these suggestions fail - touch bases with me for other options: bill[at]nodalninja[dot]com.

Cheers
Bill
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Tom Vogel

Posts: 27
Location: Cambridge, Ontario, Canada
Registered: 5 Mar 2007
Re: Constant drift - is this fixable with my NN3
Posted: 10 May 2008 at 16:05 GMT
Hi all,

Thanks for the swift and helpful feedback. It's encouraging to discover that my dilemma is quite common ... and to be expected. I'm pleased to hear that imrpovements can be made however.
I'm very interested in the T1 points. I've never used them before - I'm almost ashamed to admit. I'll check John's tutorial on that. I always thought T1 points were for serious tilts and damage control. I think 40 seconds can be afforded in each stitch smile . Thanks John!
I'll order that new rotator - thanks Smooth.
And thanks to all of you for coming to my aid with sound and sensible advise. You can't pay enough for information like this.

By the way - John - you mentioned that I shouldn't click on Align after I apply a template. I've got a great template series for my different sized files (I created them from an elaborate shoot that rich details in every inch of the pano. Are suggesting that I simply open the template with my loaded images and then create the pano - no optimising etc? If so - this may make an incredible difference to my workflow and image output.

I'll try this all out (and start shooting with a new rotator ASAP).

So grateful!

Tom
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Skridlov

Posts: 127
Location: United Kingdom
Registered: 12 Nov 2007
Re: Constant drift - YES this is fixable with my NN3
Posted: 10 May 2008 at 16:13 GMT
updated: 10 May 2008 at 16:16 GMT
Hi Bill
I have to say that the tensioning method you describe is the method I use and it's hit and miss at the best of times. Not that much of a problem, more an inconvenience. I haven't tried tweaking the detent plunger tension but since I changed to the 60 deg washer the rotation is graunchy and the detent click hard to feel.
I will upgrade (Red Door) as suggested assuming that it's not too expensive.
Roy
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Tom Vogel

Posts: 27
Location: Cambridge, Ontario, Canada
Registered: 5 Mar 2007
Re: Constant drift - YES this fixable with my NN3
Posted: 10 May 2008 at 16:14 GMT
HI Bill,
Sorry to not mention you in the thanks list - your advise was helpful before as well. I've followed those earlier instructions (as you've posted them here) and I think the new Rotator is the answer. The tension screw on mine seems to have become ineffectual. It used to work like a charm (I could rotate either way and not have it come loose). I've placed the second washer in as well - in an attempt to restore the fluid action. Not much luck, however. All that said - I adore my NN3. I worked with a Panasuraus for over a year and the Ninja is an incredible step forward for me in the work I do on a daily basis.

I'll contact Rosario today and order that new Rotator.

Thanks again - Tom
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John Houghton

Posts: 2265
Location: Hitchin, United Kingdom
Registered: 17 Jan 2005
Re: Constant drift - is this fixable with my NN3
Posted: 10 May 2008 at 16:52 GMT

Tom Vogel said:

you mentioned that I shouldn't click on Align after I apply a template. I've got a great template series for my different sized files (I created them from an elaborate shoot that rich details in every inch of the pano. Are suggesting that I simply open the template with my loaded images and then create the pano - no optimising etc?

Tom, no. I'm suggesting that you add the images, apply the template to assign a wonderful set of lens and image parameters. Then generate some control points via the Generate Control points menu or manually. You don't need a lot and the spread isn't particularly important since you won't be asking the optimizer to evaluate the lens parameters. Why would you? You already know them. A minimum of two control points per overlap are sufficient to align the images with each other when the lens parameters are known. OTOH, two would not be enough to evaluate lens parameters. You just need to be aware of what you are trying to accomplish when running the optimizer. For example, if you think you can rely on the pitch and roll values being the same for all the images in a row, you can link those parameters for optimization and manage with just one control point per overlap! Of course, it's always better to have a few more points than the minimum, to protect against minor inaccuracies in cp placement. You'll get an averaging effect, hopefully.

John
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Nick Fan
[NodalNinja]

Posts: 277
Location: Hong Kong
Registered: 26 May 2006
Re: Constant drift - is this fixable with my NN3
Posted: 10 May 2008 at 17:05 GMT

Skridlov said:

Also the +/- 90 deg setting is ... interesting. If you align the vertical post and the camera arm so that there is no apparent displacement (ie they are parallel by eye and touch) the bezel markings certainly won't read 90 deg. They won't even read the same on both sides!


Hi Skridlov,

The markings can be adjusted by rotating the angular index ring. There is a little hex key in the package. loosen the little screw in the ring and adjust the 90 deg mark to the right position. Tighten the screw gently and you are done.
There are no way we can guarantee alignment of 0 deg and 180 deg reference marks. Infinite precision is required. I put the second mark for convenience. Different people may prefer using NN3 in different orientation. In any case, you only need to refer to a single mark. and you can adjust the index ring for corresponding reference mark. The other mark has no effect on you. NN3 is not a measuring instrument. we build it for adequate precision for making panos. Typically 20-30% overlap is recommended. The precision of NN3 is exceeding this requirement.


Nick
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