Vignetting ang gigapixel panoramas

[George Palov]

Hello,

I am writing here because I am struggling to get things right with this pano. I've shot a 340 photos panorama of a mountain region and /like almost always/ getting seams in sky from /I guess/ vignetting. There are 10 images in each column, shooting bottom -up from left to right with 25% overlap. I am sending a link to 90 of the images to the left of the pano, native Nikon RAW files from the camera. ~ 2Gb. There is a PtGui project files with jpegs with the same names, but one can just use the align to grid function /what I actually did/. So, what I have tried so far- exporting from LR with flat camera profile and only remove CA, then the same but with lens profile and vignetting correction, then the same + manual /by eye/ correction of vignetting, all with the same bad result. I also did try DXO and it's only optical/vignetting/CA correction, again similar results. In PtGui I do align the images after they are loaded into the grid, and then I do Optimize in "Automatic exposure and color adjustment" again with different options in the corresponding panel settings. Things get little to no better at all.

Link for raw test files if someone should give it a try. Link is vali for 7 days only.

https://we.tl/t-lIe3gCCOd2

I think I've read all the topics here on vignetting but with no luck. Wonder if I should use different settings when shooting like aperture or shutter speed. I was taking photos with VR Drive in automatic mode, Nikon D500 crop camera and Tamron SP 150-600mm f / 5-6.3 Di VC USD G2 with VC ON, f8, 1/1600, ISO 100, 150mm

Wonder about aperture mechanical differences when triggering, taping the lens connectors for aperture control /tip from another pano guy/, etc

Hope there is SOME workflow/repeatable solution to this as it is very annoying :)

[PTGui Support]

Hi George,

I think this may be caused by bad shutter curtain synchronization in
your camera. If the shutter opens and closes with different speeds, one
side of the image is slightly longer exposed than the other side.

In portrait orientation this would result in vertical banding like in
your image. The effect would be stronger at short shutter speeds.

PTGui currently cannot correct this (only radial vignetting) but
supporting this is on the wish list for a future version.

Kind regards,

Joost Nieuwenhuijse
www.ptgui.com

On 07/03/2022 20:20, George Palov wrote:
> Hello,
> I am writing here because I am struggling to get things right with this
> pano. I've shot a 340 photos panorama of a mountain region and /like
> almost always/ getting seams in sky from /I guess/ vignetting. There are
> 10 images in each column, shooting bottom -up from left to right with
> 25% overlap. I am sending a link to 90 of the images to the left of the
> pano, native Nikon RAW files from the camera. ~ 2Gb. There is a PtGui
> project files with jpegs with the same names, but one can just use the
> align to grid function /what I actually did/. So, what I have tried so
> far- exporting from LR with flat camera profile and only remove CA, then
> the same but with lens profile and vignetting correction, then the
> same + manual /by eye/ correction of vignetting, all with the same bad
> result. I also did try DXO and it's only optical/vignetting/CA
> correction, again similar results. In PtGui I do align the images after
> they are loaded into the grid, and then I do Optimize in "Automatic
> exposure and color adjustment" again with different options in the
> corresponding panel settings. Things get little to no better at all.
> Link for raw test files if someone should give it a try. Link is vali
> for 7 days only.

> https://we.tl/t-lIe3gCCOd2 <https://we.tl/t-lIe3gCCOd2>

> I think I've read all the topics here on vignetting but with no luck.
> Wonder if I should use different settings when shooting like aperture or
> shutter speed. I was taking photos with VR Drive in automatic mode,
> Nikon D500 crop camera and Tamron SP 150-600mm f / 5-6.3 Di VC USD G2
> with VC ON, f8, 1/1600, ISO 100, 150mm
> Wonder about aperture mechanical differences when triggering, taping the
> lens connectors for aperture control /tip from another pano guy/, etc
> Hope there is SOME workflow/repeatable solution to this as it is very
> annoying :)
>
>

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[George Palov]

Hi Joost, thank you for the input.

I was using electroinic shutter in Live view, not the mechanical one if this matters.

Do you think this can be tested in Lab to see if there is a problem?

[PTGui Support]

I guess you could try photographing a grey wall. Then rotate the image
180 degree and compare with the original.

I came across this:

https://johnplatt.com.au/electronic-shutters-banding-rolling-shutter-explained/

By the way, beware of rolling shutter when using electronic shutters! If
you use a motorized panoramic head, make sure the camera has come to a
complete stop before triggering the shutter. I've seen rolling shutter
causing weird stitching errors.

Kind regards,

Joost Nieuwenhuijse
www.ptgui.com

On 08/03/2022 12:30, George Palov wrote:
> Hi Joost, thank you for the input.
> I was using electroinic shutter in Live view, not the mechanical one if
> this matters.
> Do you think this can be tested in Lab to see if there is a problem?
>
> On Tuesday, March 8, 2022 at 1:25:33 PM UTC+2 PTGui Support wrote:
>
> Hi George,
>
> I think this may be caused by bad shutter curtain synchronization in
> your camera. If the shutter opens and closes with different speeds, one
> side of the image is slightly longer exposed than the other side.
>
> In portrait orientation this would result in vertical banding like in
> your image. The effect would be stronger at short shutter speeds.
>
> PTGui currently cannot correct this (only radial vignetting) but
> supporting this is on the wish list for a future version.
>
> Kind regards,
>
> Joost Nieuwenhuijse

> www.ptgui.com <http://www.ptgui.com>

> <https://groups.google.com/d/msgid/ptgui/CAG%3DfYH9u627RC%3DfOYseC34tiwMf1egRFBUvQhfObj1zjXOE3kw%40mail.gmail.com?utm_medium=email&utm_source=footer
> <https://groups.google.com/d/msgid/ptgui/CAG%3DfYH9u627RC%3DfOYseC34tiwMf1egRFBUvQhfObj1zjXOE3kw%40mail.gmail.com?utm_medium=email&utm_source=footer>>.

>
>
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> You received this message because you are subscribed to the Google
> Groups "PTGui Support" group.
> To unsubscribe from this group and stop receiving emails from it, send
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> <mailto:ptgui+un...@googlegroups.com>.
> To view this discussion on the web visit

> https://groups.google.com/d/msgid/ptgui/49760378-74ef-40d6-8eac-45b1974f89ccn%40googlegroups.com
> <https://groups.google.com/d/msgid/ptgui/49760378-74ef-40d6-8eac-45b1974f89ccn%40googlegroups.com?utm_medium=email&utm_source=footer>.

[John Houghton]

On Tuesday, March 8, 2022 at 11:25:33 AM UTC PTGui Support wrote:

In portrait orientation this would result in vertical banding like in
your image. The effect would be stronger at short shutter speeds.

PTGui currently cannot correct this (only radial vignetting) but
supporting this is on the wish list for a future version.

One way to correct this it to create an action in Photoshop that applies an adjustment of levels/brightness/exposure with a L-R graduated selection. (See http://www.johnhpanos.com/gradtut.htm ).  Then in Bridge, convert the raw images to tiff using the batch option  Tools->Photoshop->Image processor, specifying the action  you have created.

John

[George Palov]

Thank you John, Joost.

I gave the camera 3 seconds wait after the move of the robot, so should be enough. About the other suggestions I will read and investigate further. Might try shooting with lower speed and even try the mechanical shutter, but that could give mirror slap shake. Tough choices.

[Erik Krause]

Am 08.03.2022 um 12:44 schrieb PTGui Support:

> I guess you could try photographing a grey wall. Then rotate the image
> 180 degree and compare with the original.

Better to rotate the camera by 180° and take a second image. A wall is
seldom evenly lit...

However, the effect of unevenly moving shutter curtains is more of a
problem with high shutter speeds. If only a small slit is moving across
the sensor, a tiny variation in the width of this slit (because one
curtain moves faster than the other) will result in a large exposure
difference. In theory this should not happen with electronic shutter,
but who knows? Anyway, use of a slower shutter speed should reduce or
eliminate the problem. And while an electronic shutter is fast in terms
of exposure it nevertheless might take longer for the whole image than a
mechanical one (see the link Joost provided).

--
Erik Krause
http://www.erik-krause.de

[George Palov]

Thank you Erik! I recently shot a similar pano and the shutter speed was 1/800, F9 and this banding was NOT present. So I guess this is the way to go (for me), use slower shutter speed. I will try a new one soon. Now I am trying to make a mask/linear gradient in Lr to compensate for the brightness difference in this set, just have to figure which side to brighten, left or right.

[John Houghton]

On Tuesday, March 8, 2022 at 6:47:51 PM UTC gpa...@gmail.com wrote:

Now I am trying to make a mask/linear gradient in Lr to compensate for the brightness difference in this set, just have to figure which side to brighten, left or right.

In my test with a layered PSD output of two images, I found increasing the exposure by +0.1 worked quite well, though it was not possible to eliminate a visible join completely before PTGui's blender got to work.  The the shots were taken over a significant time during which cloud conditions were no doubt changing.

John

 

[George Palov]

Thank you John,

I made a gradient in Lr from left to right and -0.20 exposure. This is the result (much better though not ideal)

https://panomagic.eu/gigapixel/hija-Yastrebets/

G

[John Houghton]

On Monday, March 14, 2022 at 7:48:48 PM UTC gpa...@gmail.com wrote:

I made a gradient in Lr from left to right and -0.20 exposure. This is the result (much better though not ideal)

Yes, that's a lot better.  It might be worth trying to refine the gradient with a curves adjustment using a test shot of a uniformly lit plain white or grey surface (close up to and out of focus with same lens and exposure settings).

John