Stitching problem

[Stanley Green]

Here is a segment of a single row, eight-shot sequence pano (180 degrees). I used a Canon 5D2 with a 24-105 f/4 lens (24mm, f/11) mounted on a tripod with a nodal rail and a Sunwayfoto 64M rotator. Since the bubble level on the tripod gave less than satisfactory results, I leveled the pano head at orthogonal settings with a small flat level.

While the suggested index angle for a 24mm lens was 30 degrees, the first time I tried it, Hugin was unable to find enough control points. So, I reshot the sequence using a  20 degree rotation in order to have more overlap. Both segments were then stitched (cylindrical) using the same input shots, only the stitching application was changed. I estimate that at the 20 degree rotation I had about 50% overlap.

Here is shot #3 from the sequence that shows how it really looked.

Stitched with Hugin

Comparing the two images, Hugin seems to have done a better job keeping the street light vertical. However, if you look at the area at the bottom and to the right of the street light, you can see that Hugin introduced an obvious stitching error.

[Bruno Postle]

This looks like the angle of view for the photos is incorrect, can you attach the PTO project file that shows the problem (no need to attach the photos)?

--
Bruno

On 12 September 2021 15:14:18 BST, 'Stanley Green' wrote:
>Here is a segment of a single row, eight-shot sequence pano (180 degrees). I used a Canon 5D2 with a 24-105 f/4 lens (24mm, f/11) mounted on a tripod with a nodal rail and a Sunwayfoto 64M rotator. Since the bubble level on the tripod gave less than satisfactory results, I leveled the pano head at orthogonal settings with a small flat level.

[Stanley Green]

Bruno,
Not sure what you mean by, “the angle of for the photos is incorrect”, but here is the PTO file.

[Stanley Green]

Bruno,
I sent the wrong PTO. Here is the correct PTO, there is still one stitching error.

[Bruno Postle]

Hi, attached a PTO file that should give better results.

Basically the problem is that the angle of view (v) parameter for your
photos was set to 44.7 degrees, probably because your camera is
reporting an incorrect focal length - this is very common with zoom
lenses.

So I re-optimised the project using the 'positions and view' option in
the Photos tab and calculated a better angle of view of 49.9 degrees.

--
Bruno

[Stanley Green]

Bruno,

Thank you. It is obvious that I have a great deal to learn about Hugin and how to get the best results.

Where would I find a set of instructions that I could use to correct the images? I went to the Hugin Tutorials page and to say the least, it is overwhelming.

The Hugin tutorial - "Stitching two photos together” seems like a good starting point. While it explicitly addresses two images, I assume that I could extrapolate it to eight images.

As of now, I am only interested in creating simple single row, 180-degree panoramas. I assume that I will have to make the “v" correction if I change lenses or use a different zoom setting; can you point me to a tutorial that shows how would I go about making the corrections?

Thank you for your help and your patience,
Stan

> On Sep 13, 2021, at 3:44 AM, Bruno Postle <br...@postle.net> wrote:
>
> <GF pano 1 - GF pano.pto>

[Bruno Postle]

We are lacking tutorials, maybe even some videos would be useful.

In particular the Assistant in the Fast Preview window has a nice 1. Load, 2. Align, 3. Stitch workflow which do lots of steps in the background, and which are sufficient for most purposes.

What isn't clear is that the steps behind these buttons can also be performed manually by following the tabs in the Panorama Editor from left to right, and running the appropriate tools one at a time - relating this to the Assistant would be a good angle for a tutorial.

So a short video might stitch a panorama with the Assistant, but then show how to handle common misalignment problems.

Another video might stitch a panorama with the Assistant, then discuss cropping, projection and output resolution issues.

etc.. etc.. any volunteers?

--
Bruno

[jmuc...@gmail.com]

On Wednesday, 15 September 2021 at 07:27:50 UTC-4 bruno...@gmail.com wrote:

In particular the Assistant in the Fast Preview window has a nice 1. Load, 2. Align, 3. Stitch workflow which do lots of steps in the background, and which are sufficient for most purposes.

What isn't clear is that the steps behind these buttons can also be performed manually by following the tabs in the Panorama Editor from left to right, and running the appropriate tools one at a time - relating this to the Assistant would be a good angle for a tutorial.

I'll go further: it's not very clear at all that that little button (which doesn't have "Fast Preview" in its tooltip, btw) does that at all. I'd expect something so powerful to be big and obvious in its function.