Vignetting artefacts by RAW mode

[Mikhail Prokopenko]

Hi, PTgui World!

I stitch RAW pano and have an issue with my SONY DSC RX10M IV camera at 24mm: the source files have severe distortion and vignetting. PTGui handles the distortion but not the vignetting. As a result, black artifacts appear in the resulting panorama. Can I fix this problem in PTGui, or do I need external tools?
Project files you can find at https://drive.google.com/file/d/1A1x_zhq107FyrzKwUbtaMIHjdXi3JKSn/view?usp=sharing

[John Houghton]

Mikhail,  I am unable to identify any "black artifacts" in your image, other than the black corners, which should be eliminated with the mask tool.  I do see chromatic aberration and parallax issues.  The setup of your panorama head should be improved to rotate the camera about the no-parallax point.  The chromatic aberration can be corrected on the RAW Pre process tab.

John

[Mikhail Prokopenko]

Hi, John

Thanks for the prompt replay.

This is hand-held pano and that is an issue, I guess.

By "artifact" I meant the dark "outer" corners (see upper left pano corner below). I believe such problems because of  camera positioning during shooting. In this case, vignetting at the outer corners remains, while PTGui handles vignetting at the inner corners of the frame correctly.

среда, 10 июня 2026 г. в 13:56:42 UTC+3, John Houghton:

[Erik Krause]

Am 10.06.2026 um 15:36 schrieb Mikhail Prokopenko:

> In this case, vignetting at the outer corners remains, while
> PTGui handles vignetting at the inner corners of the frame correctly.

I suspect that the inner corners are disappearing in the overlap area.
The outer corners look as though they are at the edge of the image
circle, or as though there is something in the light path, such as a
sunshade that is too narrow or something similar. This is not a typical
case of vignetting and therefore cannot be corrected. There is simply no
light present.

Just note that the raw converter used by PTGui (libraw) doesn't crop the
image in the same way as the camera or other raw converters do. This may
be the reason why the image circle is visible.

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

[John Houghton]

On Wednesday, June 10, 2026 at 4:37:35 PM UTC+1 Erik Krause wrote:

The outer corners look as though they are at the edge of the image
circle, or as though there is something in the light path, such as a
sunshade that is too narrow or something similar. This is not a typical
case of vignetting and therefore cannot be corrected. There is simply no
light present.

Yes, I assumed the black corners were just the edge of the image circle and masked them out as one does for circular fisheye images.  The corners make no contribution to the final image so discard them so that they cannot inadvertently cause problems in the blending.

John

 

[Erik Krause]

Am 10.06.2026 um 17:37 schrieb 'Erik Krause' via PTGui Support:

> Just note that the raw converter used by PTGui (libraw) doesn't crop the
> image in the same way as the camera or other raw converters do. This may
> be the reason why the image circle is visible.

It really is down to the image circle. Whilst the ‘official’ resolution
is 5472 x 3648 pixels, PTGui uses 5496 x 3672 pixels, but that alone
does not explain the corners. It is simply the extreme zoom and,
apparently, Sony’s desire to achieve a focal length of 24 mm
(equivalent) that result in the image being larger than the lens’s image
circle.

[PTGui Support]

I haven't tried, but I suspect raw converters like ACR have a built in
profile which warps the image into a perfect rectilinear image. Probably
without telling the user.

It's cheaper (and probably better) to do this in software than
attempting to create the perfect 24-600 mm optical zoom lens.

Kind regards,

Joost Nieuwenhuijse
www.ptgui.com