panorama - bug with whitebalance
Create a panorama with version 22 for Windows, then use auto adjust. There will be a big colour shift. That is because the White Balance Mode drop down is reset to off. Whatever the previous setting was, it is lost.
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Are you using a fixed WB setting for all of the images used to create the Panorama?
I see the same sort of WB shift (compared to the original value "Shot") if using the Auto WB adjustment directly on one of the original images. Basically I think this represents a difference in the way that C1 assesses a "default" WB for an image compared to the way my camera (Canon in this case) has assessed the shot when taken.
The image in a pano stitch all showed similar WB values as shot and one of those values was adopted for the stitch DNG. However, using the Auto WB option for any of the source images or the resulting DNG significantly warmed the image.
Using the WB tool dropper in areas of the image that were, nominally, all possible sources of something close to a mid-grey sample produced some significantly different results. Cloud areas generally were aligned with the camera's assessment. Other areas offered results all the way from the "cloud" values to the Auto WB assessment values and a little beyond.
It does seems a little strange to have so large a change in the case of the images I am using but it's all consistent whether the stitched DNG or the original RAW files are being Auto processed.
Whether it should be like that at all is probably the more significant question. Personally I have no problem with what happens because I am requesting a re-assessment of the image and that is what I get. I don't have to like it!
But I do appreciate that others may feel differently about the subject.
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All my images are taken in RAW with the camera on auto white balance. If I want to change the white balance later, I can do that during processing. For the panorama, I was experimenting using images with no processing, other than that applied by C1 by default (I left the Curve on default and did not, for example, choose Linear Response). I did not change the WB on any of the input images before creating the pano.
At some point, once the pano is created, white balance is no longer retained at "shot" in the pano image. I haven't done any testing, but possibly if there was a small change in the white balance across the input images, then C1 does not know what "shot" means any more, and therefore no longer accepts "shot" as the WB setting: I don't know, that is just a guess. Come what may, something throws out the "shot" setting and produces a major colour shift, which is not at all helpful, although it is easy enough to correct once you know the cause, merely by reinstating "shot" as the WB in the pano.
I watched David's and Paul's helpful YouTube videos yesterday. They recommend at least setting Lens Correction Light Falloff for all the input images to 100%. If that is the best setting, it would be a good idea to have a check box when the pano is being created which will automatically allow you to choose to have this setting applied (or apply it automatically, with a check box allowing you to turn it off if you do not want it). It is not very user friendly to have to have to remember to take at least one specific process step before creating each panorama (and anyone who has not seen the video would not be aware of this anyway). One for a future point release, I think.
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Just tried my first merge to HDR (which looked pretty good to me).
Same thing happens. Merged DNG file looks good, press any "auto" tool and WB changes from "shot" to "custom".
I am sure this is not intentional behaviour, and is a bug.
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had to put this in the version 21 section, because this has not yet caught up with version 22 having been released!
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Graham,
As you know the WB is not part of the final processing of the image - just a (usually decent) estimate from the camera to provide a baseline to work from.
My own experience has been that the pano process will use WB settings that relate to the values provided by the RAW input files. The inputs I have used have all been very similar as one would expect and the resulting WB for the stitched panorama has been in the same range. Indeed it may have selected the most commonly used value from the sample sets - not sure. I would need to do some more comparisons or, better, have the relevant choice info provided in the User Guide documentation.
Only if I subsequently auto-adjust the DNG after creation does the WB seem to be warmed up noticeably. (In my sample image which was using images of a seaside townscape from an elevated position on a heavily overcast day.) The OOC WB values as shot were in the range 5500 to 5990 (approximately), The auto-adjust via the WB tool, having been asked for something different, settled on around 6500 to 6600. The tint setting was broadly in line with the range in the original files and pretty much 0.
This seems to be consistent over a couple of sessions taken in different light conditions using the same camera and lens. Auto-adjust will warm the WB setting. I see the same result creating merged HDR images and varying the selection for applying Auto-Adjust during the creation process or applying it afterwards.
It's the same for a single image using the same camera and lens.
From memory, this has always been the case. However, whether the degree of change is different to previous versions I have not yet considered. I have not, historically, used Auto-Adjust at all and my default settings for the tool exclude WB adjustment - probably because I find the Warm up adjustment a little too warming for most of my requirements.
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