And still... massive problems with the sky - color and blending

@bo - I may be wrong, but my perception is that blending of the sky has improved with recent releases too, perhaps Alexandre would like to comment?

One thing is for certain though, speaking as someone who has bought, and regularly tries out, all the major panorama stitching programs out there, Autopano remains the best solution for the kind of panos that I shoot. There are aspects of the other solutions that I would like to see in Autopano - particularly with regards to the layout of input photos (awaiting a firmware update from my pano head manufacturer that will probably negate the need for Kolor to do anything on that front though), but in my experience, when it comes to the production of the output panorama, Kolor are in a league of their own.

Great to see that the blending issue is recognized, and that it is being addressed.

Regards,

Gerald.

gddxb wrote:

@bo - I may be wrong, but my perception is that blending of the sky has improved with recent releases too, perhaps Alexandre would like to comment?

Yes, we are improving that part too. It's not easy because it is theoretically complicated, but beta 4 has improvements and the RC 1 will have other improvements too.
We are getting better and better.

Quite for sure, this is vignetting. It gives these typical darken zone at corners of images.

AlexandreJ wrote:

Quite for sure, this is vignetting. It gives these typical darken zone at corners of images.

The Olympus 50mm is an old OM-lens, made for 24x36 fullformat. Used at a crop 2.0 camera stopped down to f8.0.
I don't think the dark bands are from vignetting.

I have done some more experimenting:
- I have de-vignetted the images i DXO, in strength 20 and 50
- the result on an image from the sky shown below
- then I swapped in the de-vignetted images and rendered the pano
- examples from the rendered pano shown below

The verdict:
there are dark bands in the sky even with the extremely "de-vignetted 50"
what's the problem? I don't know
is it the lens alone?  I don't think so

Kolor should take another look at this.
As more motors get available there will be more people shooting giga-spheres, which will include the sky.
Then there will be more skies with dark bands and more posts about the phenomena.

Leif

Last edited by leifs (2011-10-30 14:09:09)

Okay. Not easy to conclude. I did the following test to measure a little bit more the vignetting part in the provided image.
Vignetting is symmetric, so when rotating the image, it should be reflected the same in any direction. So I took the provided image and made symmetric version of the same image and aligned them around the original image. If the image was suffering only from vignetting, you would see no seam at edge ( you can do the test with the grey vignetting image generated ).

So, it shows that images have a color gradiant with a direction, but also some vignetting but not strong it seems. I don't know what to think yet and to make conclusion, it would require for example a small extract of the panorama in the sky like 4 images forming a 2x2 matrix. This could help to measure the gradiant component compared to the vignetting component. Could you provide us 4 full resolution images from the panorama ( from the sky of course ) ?

I use APG 2.60b4.

There is a package of TIFF files for download at   www.rundskuer.no/ymse/kolor.zip
(the images were shot as ORF and converted to TIFF using Olympus Master software)
It contains 8 images from the sky as shown below. The images close to zenith is stretched a lot in the resulting pano, also shown below.
To pinpoint where in the sphere the images were shot I have included the XML used for import.

I hope this can be a help to solve the dark-band-in-the-sky problem.
I will also shoot some spheres with other lenses to see if there are more or less bands.

Leif

Last edited by leifs (2011-10-31 22:34:19)

I used your package to create a .pano project file that just contains this extract.
I did 2 renderings in PSD format with embedded images to look at the vignetting. On the top of each layer, I added a level layer to raise drastically contrast on analysed zone.
Here's the results :
* first screenshot : just some images revealed. When you look at corners, obviously, there's vignetting, but it rapidly drops after 10% inside the image. The formula of this vignetting here has a quite quick reduction.
* second screenshot : that's the rendering done, with every settings by default on the 2.4 RC1 engine. It seems that the fixes made reduces a little the issue we can see in your rendering and not in this one.
* third screenshot : no anti-ghost, diamond weighting. This has always been the right solution for nice skies, but it isn't good at all for ghost or ground. You can guess it by looking at tree top.

Perhaps, we can go more deeply in the vignetting measurement. Adobe released a tool whose aim is about that : adobe lens profile creator. It does measure lens distortion but also vignetting effect. If you remember the lens and aperture used, we could try to make some shots in the same condition on a white paper to measure the vignetting well. Then use this profile in either photoshop to postprocess the images or in autopano through the open lens plugin. I think it will solve some of the issues, but not all of them. There's a gradiant in these images I cannot explain and I don't think it comes only from the sky natural gradiant.

I appreciate very much the interest in users troubles from Kolor ! That makes me want to give something back, to make APG better.

And I'm still struggling with the sky.
This time I shot a sphere using Olympus E-P3 with a Panasonic Leica DG Summilux 25mm f1.4 ASPH lens. This is a prime lens and tests show very little vignetting stopped down to f2.8. I shot the sphere at f8.0.

In my search for a smooth sky I tried three different rendering settings:
- simple
- multiband diamond
- antighost

The "simple" setting gives me the smoothest sky, but even there I can see patterns from the single images
Multiband shows more patterns and antighost shows even more.
The "simple" setting cannot be used if there are anything moving in the pano, without a lot of postprocessing.

Is there anybody who has been tweeking the the blending setting and found a good combo for a smooth sky ?

Leif

BTW : did you try with RC2 ? It should also have improved a lot ( especially in RC2 + level 0 in multiband ).

leifs wrote:

There is a package of TIFF files for download at   www.rundskuer.no/ymse/kolor.zip
(the images were shot as ORF and converted to TIFF using Olympus Master software)

Can you provide three or four RAW files?

best, Klaus

Last edited by klausesser (2011-12-15 16:08:05)