Difference between raw and jpg

[Paul Bourke]

I have my camera set to save both raw (Canon CR3) and jpg images. In a recent 360 cylindrical panorama, (single row of 15 images) when I use the CR3 images one image doesn't get included even though there is lots of overlap. But when I use the jpg images things work perfectly. Ideas why?

[PTGui Support]

Hi Paul,

The image data is stored differently; raw files are linear while jpeg
files have a gamma curve applied. Usually this doesn't matter but if
there are few opportunities for PTGui to find control points then it
might just make the difference.

If you see consistent worse behavior please send me a set of files and
I'll investigate.

Kind regards,

Joost Nieuwenhuijse
www.ptgui.com

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[Paul Bourke]

The images are sharp and well lit.
There is no shortage of control points.

Would you mind taking a look at the images, I've put them here
https://paulbourke.net/transient/ptgui/
I can go in and force the inclusion of the missing image by explicitly
asking for control points between image n-1 and n, and n and n=1, I
want to minimise the need for this manual intervention ... and it
seems to screw up the aspect ratio. Note this is the left eye of a
stereo pair.

I'm using PtGui 13.9 on MacOS. Stitching cr3pano1 always leaves one
image out. Stitching jpgpano1 always works, repeatable for me.

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Paul Bourke
paulbourke.net
paul....@gmail.com
+61 433338325

[PTGui Support]

Hi Paul,

I tried a few times. Both with the jpg and the cr3 images, a few times
one of the images did not have control points, while other times all
images had control points. So I think it's merely an edge case, it's not
caused by the file format itself.

I think this is caused by the significant parallax. PTGui finds control
points between neighboring images. But when it tries to connect the
first and last image (to close the 360 degree circle) the accumulated
accumulated parallax errors becomes too large and PTGui deems the
control points to be invalid.

I'll see if this can be improved.

Kind regards,

Joost Nieuwenhuijse
www.ptgui.com

[Paul Bourke]

Hmmm, I'm still not sure how that explains why, for me, the jpg
sequence is always successful.

Regarding parallax, yes because it's a stereo pair, each camera will
be offset by 35mm. The test I sent has a larger separation since I
used my larger Canon R5. I'm currently building the next iteration
using the Canon R50V which will be much closer to 35mm.

Thanks for investigating.

On Tue, 28 Jul 2026 at 20:50, 'PTGui Support' via PTGui Support

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