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White Balance w/ LCC and C1
- Thread starter rga
- Start date
GrahamWelland
Subscriber & Workshop Member
Btw in case folks haven't noticed it, they added an option in C1 7.2 to set the default ICC for the camera by model. So now landscape folks can set their ICC to Outdoor Daylight/Film curve vs Flash v2. :thumbs:
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Torger: I have been thinking the same thing here (about the wb) so I can either take one of the 4 tungsten lamps I am using to light the painting and shine it directly at the LCC plate for the LCC shots, or simply replicate the whole thing back at the studio with a white card and perfectly even lighting, then apply there.
Not sure which way I will go yet. Knowing me, probably all 3! Just to see which works best. The painting is way too large and too high up in the air to cover with white paper or sheet. But if I could that's what I would do.
Finished shoot of 14ftx11ft painting 25ft in air on scaffolding! All went well and pulled it off
creating a 6 frame stitch using 80MP Credo 80 on Sinar P2 using sliding back. Almost 1.5GB file of incredible quality produced. (Layered file is over 4GB!)
Even though the results are outstanding, the process was very tedious; and white balance, even using LCC corrections for each 16 sec exposure + gray card exposures helped smooth things....it required hours in photoshop.
I will not do this method on the next one. I am investigating other solutions for this type of work including multistich back or getting away from 4x5/tech cam altogether and using DF and pan tools or rail system.
Will start new thread about this experience soon with some pics.
creating a 6 frame stitch using 80MP Credo 80 on Sinar P2 using sliding back. Almost 1.5GB file of incredible quality produced. (Layered file is over 4GB!)
Even though the results are outstanding, the process was very tedious; and white balance, even using LCC corrections for each 16 sec exposure + gray card exposures helped smooth things....it required hours in photoshop.
I will not do this method on the next one. I am investigating other solutions for this type of work including multistich back or getting away from 4x5/tech cam altogether and using DF and pan tools or rail system.
Will start new thread about this experience soon with some pics.
A question/clarification, did you need to further tune the white balance when stitching inside photoshop? In other words, did the LCC procedure succeed to equalize the white balance 100%, or did the shots still differ a bit?
I ask because I'm trying to write software that will make this type of workflows a bit easier.
Hi torger,
Yes, white balance was not consistent.
I believe it was due to competing color corrections between the LCC and the gray cards but there is so much going on in terms of shifting, cross polarizing, angles of incidence, individual lens behavior, sensor pixel crosstalk...that I can't see how to mathematically map it. I think if I can stay away from shifting within center of ic that would help greatly, talking to Myko at multi stitch about it now. Also trying a 15 ft rail xy platform for the DF camera and 120mm macro (my sharpest lens)
Very interested in your efforts, though
Yes, white balance was not consistent.
I believe it was due to competing color corrections between the LCC and the gray cards but there is so much going on in terms of shifting, cross polarizing, angles of incidence, individual lens behavior, sensor pixel crosstalk...that I can't see how to mathematically map it. I think if I can stay away from shifting within center of ic that would help greatly, talking to Myko at multi stitch about it now. Also trying a 15 ft rail xy platform for the DF camera and 120mm macro (my sharpest lens)
Very interested in your efforts, though
Torger: here is some idea of what we are dealing with. Look closely at the line going down center of this closeup where 2 of the 6 frames needed stitching. This is after LCC and gray card corrections. see it go yellow on left...blue on right? 3rd pick shows (loosely) the 6 frames needed to make the stitch.
Trying to find time for new thread but takes time to get all the screen shots and writing.
Jim, I am thinking of converting 2 rails from my high-glide system to be camera holders and connect them to encoders/servos
Not easy task but do-able. The hard part is the programming of the computer control into C1
Trying to find time for new thread but takes time to get all the screen shots and writing.
Jim, I am thinking of converting 2 rails from my high-glide system to be camera holders and connect them to encoders/servos
Not easy task but do-able. The hard part is the programming of the computer control into C1
re-thinking it, if you set up the camera in three horizontal positions, you will have to control glare at each position. might be tough.
given the forgiveness of stitching software, why do you need servos for positioning? seems like keeping square to the painting is the most critical, overlap less so
given the forgiveness of stitching software, why do you need servos for positioning? seems like keeping square to the painting is the most critical, overlap less so
Jim, I think each solution is fraught with pros and cons, although I dont think glare will be much problem with cross polarized lighting. I will be more concerned with perspective issues related to 3-stitch flat with no center point, but wont know till I try. The eye is a funny thing and knows when it is being decieved by perspective. On the other hand, I dont think it will be an issue as the perspective will only be the viewer angle not the camera angle.
Servos and positioning because I dont see myself getting up high enough to adjust camera position accurately and also, the math is easy once I plug in the xy coordinates, lens, and sensor size. But you are right, it can be done manually probably just as easily. All I have to do is convince my wife that its OK to have scaffolding built 25feet in the air and then carry a 12 foot step ladder up and set that up on top of that and then carry the gear....uhhhhh I dont think she's goin fer it. I'm gettin the hands on the hips deal
Servos and positioning because I dont see myself getting up high enough to adjust camera position accurately and also, the math is easy once I plug in the xy coordinates, lens, and sensor size. But you are right, it can be done manually probably just as easily. All I have to do is convince my wife that its OK to have scaffolding built 25feet in the air and then carry a 12 foot step ladder up and set that up on top of that and then carry the gear....uhhhhh I dont think she's goin fer it. I'm gettin the hands on the hips deal
Thanks for the wb info.
It does seem that Capture One lacks a mechanism to synchronize white balance modulation between LCCs, which makes stitching more cumbersome.
This is not about the white balance in the image itself, but a reference white for the LCC shot, so the correction algorithm can know what in the LCC image that is color cast and what's neutral. Probably the C1 LCC algorithm derives this reference white from the LCC shot itself (averaging or something), and naturally when the LCC shots are not exactly the same the reference white will differ slightly, which means that LCC correction will modulate the white balance in the corrected images slightly. That is, even if you have the exact white balance settings on the LCC-corrected images, they still are slightly different.
With Lumariver HDR I recently added the possibility to use one LCC shot as white reference anchor for all other LCC shots in a stitch (you pick the LCC shot for the center position). This make white balance stable. You still need to adjust exposure though, as LCC correction affects scaling somewhat. Could make an anchor for that too, but as everyone is using inexact Copal shutters anyway (ie exposure needs adjustment anyway) I have not yet seen a need for such a feature
It does seem that Capture One lacks a mechanism to synchronize white balance modulation between LCCs, which makes stitching more cumbersome.
This is not about the white balance in the image itself, but a reference white for the LCC shot, so the correction algorithm can know what in the LCC image that is color cast and what's neutral. Probably the C1 LCC algorithm derives this reference white from the LCC shot itself (averaging or something), and naturally when the LCC shots are not exactly the same the reference white will differ slightly, which means that LCC correction will modulate the white balance in the corrected images slightly. That is, even if you have the exact white balance settings on the LCC-corrected images, they still are slightly different.
With Lumariver HDR I recently added the possibility to use one LCC shot as white reference anchor for all other LCC shots in a stitch (you pick the LCC shot for the center position). This make white balance stable. You still need to adjust exposure though, as LCC correction affects scaling somewhat. Could make an anchor for that too, but as everyone is using inexact Copal shutters anyway (ie exposure needs adjustment anyway) I have not yet seen a need for such a feature