Discussion Forum: Zoning in on perfect (NPP) via Nadir view

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Topic: Zoning in on perfect (NPP) via Nadir view

Message posted by dreamingof8a on March-29-2012 at 4:18am

China
March-29-2012
5 Posts

Hi,

I kow this is a very old post but I hope that smooth and others are still around ...
I calibrated my Panosaurus with a EOS 400D/Samyang8mm last night and found an interesting thing: without optimization in PTGUI, the nadir/tripod circle looks very good (to me anyways), but there are minor parallax issues on th efloor and also on the wall.
After optimizing, the parallax issue seem to be gone, however I can see the "tooth" effect in th enadir area. Is this normal?

Can you say something about my settings in general, do they seem fine to you? Sorry for the little sharpness, it was relatively dark and I had to use f5.6 ...

first not optimized pictures

And here after optimization

Thanks a lot!

Message posted by smooth on March-29-2012 at 7:57am

Australia
November-23-2002
5401 Posts

You must always optimize before reading the nadir footprint.

You are also best to use Smartblend as the blender when setting up your NPP. This will give you are cleaner view of the nadir footprint saw tooth edges.

Your nadir footprint images are too small to make out much. The inverted pano view serves no purpose.

Regards, Smooth

Message posted by dreamingof8a on April-01-2012 at 12:35am

China
March-29-2012
5 Posts

Hi Smooth, thanks for the reply. I hadn't realized how much the pictures were resized before upload ... anyway here's a new attempt.
The overall stitching result is good, also the footprint circle looks good IMHO however as you can see I get heavy parallax errors on the nadir footprint (see scale) ... not sure if that's negligible as I'd patch that area anyway with a handheld nadir shot.

EDIT: this is now a Samyang 14mm on 5D - maybe the strong parallax happens due to the fact that with 6 pictures at 60 I am close to the limit with this lens?

Message posted by dreamingof8a on April-01-2012 at 1:54am

China
March-29-2012
5 Posts

So it's me again ... this time with the 400D/8mm combo.
Interesting thing: smartblend always managed to get the arm of the panosaurus into the nadir even though the panorama editor of ptgui didn't show it .. ended up using ptgui blender.

I find it very difficult to judge the nadir as it is not perfect at all but still pretty round ...

Thanks for any feedback!

Message posted by smooth on April-01-2012 at 4:44am

Australia
November-23-2002
5401 Posts

You can see looking at the nadir footprint that your lower rail needs adjusting to the left (when standing behind the camera).

It also appears you need move slightly backwards on the upper rail, as it looks to be compressing the circle slightly.

It is important to never allow control points to be placed on the panohead of tripod legs and just as important that control points never end up on anything that moves I.E: Shadows, People, Clouds, Trees, Branches, Cars, Buses, Boats etc.

After making these adjustments and following the guidelines, please tell me what your min/max/average control points read after optimizing.

I'm also not clear on the quality of the Panosaurus and it's limitations via flex and rotation flaws etc.

Regards, Smooth

Message posted by dreamingof8a on April-01-2012 at 9:53am

China
March-29-2012
5 Posts

hi smooth,

thanks a lot. I followed your recommendations and got the following nadir (again ptgui blending as smartblend showed parts of the panosaurus.
No control points are on the tripod nor moving things. The optimizer results were actually very good this time: min/max/average 0.6589/0.1133/1.8105 compared to previously 0.75/0.10/3.16 (which I guess is also acceptable). From this new nadir I would conclude that I moved a little too far left?

BTW may I ask for your opinion on the nadir of the 14mm/5D (see three posts up, after your initial response). The optimization results were 1.003/0.062/4.572

And yes you may be right, the panosaurus doesn't seem the sturdiest pano head....

Thanks a lot.

Message posted by smooth on April-01-2012 at 10:09am

Australia
November-23-2002
5401 Posts

Quote: Originally posted by dreamingof8a on April-01-2012
From this new nadir I would conclude that I moved a little too far left?

You conclude correct!

The Samyang 14mm Nadir looks OK. Only you know the results from the optimizer and how well the images stitched.

Just remember the NPP of a Fisheye floats depending on how the light passes through. I say if you are getting optimizer results under <3px after clicking "Remove Worst Control Points" then you have nailed it. You know you have it pretty much correct when images fall together without error.

If your really anal about finding the upper rail position, then you should also use "The Grid" method to confirm your settings. But don't expect to see much better than <3px as an average over sustained panoramic scenes.

Regards, Smooth