HDR Stitching with PTGui 13

[Tom Sharpless]

I'd call version 13 a big step forward for hdr stitching.  Last Friday, in an art gallery, I shot an hdr series from a hand supported monopod, hoping to get a usable panorama despite a big exposure difference between the walls and the middle of the room.  As usual, I took several duplicate views to raise the chances of getting enough material for a coherent pano. Also as usual, some people moved between exposures and could not be merged to a clean hdr image.  

I stitched the series twice, with version 12 and version 13, taking advantage of the fact that in both versions it is possible to disable selected exposures and still get smooth hdr tone mapping on the remaining ones.  It is also possible to mask individual exposures after unlinking their hdr sets, however in V13 I was not able to get consistent image selection and clean tone mapping in that mode, hopefully this will be corrected by release.

The biggest improvement of course is the fact that with V13 I was able to stitch direct from raw files, bypassing the usual development in Lightroom.  PTGui 13 corrects chromatic aberration and smooths camera noise just about as well as ACR does.  !! 3 CHEERS !!  The new white balance tool works nicely, too, especially in conjunction with raw development.

The V12 stitch: https://www.360cities.net/image/janies-glow-philadelphia

The V13 stitch: https://www.360cities.net/image/janie-s-glow-restitch

Overall, the V13 stitch has better dynamic range and tone balance than the V12 one, which was made from 16 bit tiffs developed in Lightroom.  Both were rendered in tonemapping mode, with similar settings. I don't see any sign that the rendering process has changed from V12.  

The first (V12) version is on a contrastier tone curve and has a slightly different white balance.  I think the second captures the overall scene better.  A slight loss of contrast in the prints near the camera is more than compensated by better contrast in the distant ones and the signage.  I selected a different shot of Janie in each stitch because I love them both.

[PTGui Support]

Hi Tom,

Great to hear that!

Indeed, when generating HDR panoramas raw files are superior to TIFF.
PTGui needs linear luminance data and raw files are pretty linear. With
TIFF files the raw converter has applied some unknown curves and other
magic, and PTGui will need to undo all of this in order to get the
linearized data.

Masking between individual brackets is not supported, this would require
a different HDR merging algorithm which blends the discontinuities at
the edges of those masks. Something for v14 perhaps.

Kind regards,

Joost Nieuwenhuijse
www.ptgui.com

> --
> 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
> an email to ptgui+un...@googlegroups.com
> <mailto:ptgui+un...@googlegroups.com>.
> To view this discussion on the web visit
> https://groups.google.com/d/msgid/ptgui/9058f318-c2b5-47d0-805b-b79a4d9d5294n%40googlegroups.com <https://groups.google.com/d/msgid/ptgui/9058f318-c2b5-47d0-805b-b79a4d9d5294n%40googlegroups.com?utm_medium=email&utm_source=footer>.