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Thread: Help - WB & Exposure when shifting

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    Help - WB & Exposure when shifting

    Some interesting behaviour with IQ180 when shifting. I suspect this is how things work, but would love to know if there is something I am missing here.

    Setup:
    Shooting with IQ180/90HRSW with polarizer
    Two frames, first 15mm left/ 0mm vertical, second 15mm left 30mm down
    WB in back set to Daylight

    Issue:
    Imported into C1, WB shows as 5000K, 0 tint on both frames
    After LCC is applied, there is a significant shift in color in both frames.
    Camera was in same position for both shots, only difference is the shift.
    Exposure was the same for both frames as well.

    I thought there was a shutter sync issue, but I have several scenes where the same behaviour can be seen.

    I also tried white balancing the LCC before applying and it gets a little better, but still a large difference. In the second set below, I manually corrected as best as I could, but still not close enough.

    Questions:
    1. Is there something I am missing at capture time? Can I do anything differently here. I guess the most obvious would be to shoot a grey card in each frame, that that gets hairy along with all the other things I need to do like shooting LCC, exposure bracketing etc.

    2. How can I get this better in post-processing in C1? Is there an easy way to match these? I had assumed WB off the sensor was an absolute value, but it appears not to be. What is the easiest way to match WB across two frames?

    Appreciate your thoughts.

    LCC applied - NO other corrections - no changes except shift - same exposure



    White balanced LCC applied - C1 manual matching of WB, exposure, same exposure at capture.



    BTW, I now see a centerfolding issue in the first frame, but lets ignore that for now

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    Senior Member Pemihan's Avatar
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    Re: Help - WB & Exposure when shifting

    I had that WB issue with my Aptus-II 7, but haven't seen it with my IQ160 and since upgrading Capture One to 8.1 the issue seems to have vanished on my Aptus-II 7 files as well..

    Now the centerfold/tiling issue...... That is an entirely other matter that I hope Capture One in a future version will be handling much better than is the case now...!
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    Re: Help - WB & Exposure when shifting

    Thanks Peter. I am on the latest C1 8.1. I am wondering if the polarizer makes things worse.

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    Re: Help - WB & Exposure when shifting

    I used the 160 and now the 260.
    On shifts with the 40mm of 12mm or more I usually see the same issue the shifted frames will exhibit an different WB. I see this more with blue skies where C1 can't seems to totally correct the color cast.

    I use a CL-PL quite often and would agree the it can make the issue worse at times especially in the lighting you samples show.

    The CCD backs really do a great job on a blue without a CL-PL but I still like to use them to cut the glare on leaves and water as the look is often much more to my liking. Most times I shoot one series with the CL-PL on and one without so it the problem shows up I can work either set of files.

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    Re: Help - WB & Exposure when shifting

    Quote Originally Posted by jagsiva View Post
    I also tried white balancing the LCC before applying and it gets a little better, but still a large difference. In the second set below, I manually corrected as best as I could, but still not close enough.
    I make much panos with my P20 + Cambo (3 pics: +-20mm plus Zero). With this combo I have the same "problem".

    Shoot all with "daylight" in the back.

    - first make a LCC for every picture
    - with the corrected LCC-picture (the white one) I make my white-balance
    (for example: left then 7700k, middle 5200k, right 5000k - all with different tones).
    - And finally I use the made LCC for my real pictures and the different white-balance-sets, too.

    Get a wonderful pano then.

    Because of I have a Cambo I have some "ready sets" for all kinds of (Cambo has all 5 degrees a mark you can re-find easy - and I use only this ones at 99.9% the time).
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    Re: Help - WB & Exposure when shifting

    Thanks Christian.

    What you described is exactly my workflow with the exception of the WB on LCC. You seem to be correcting annually, where I corrected in "Auto". Will give this a shot.

    The IQ180 is likely exacerbating this more when compared to the P20.

    It is sounding like I just need to live with this. Maybe WB card on every shot is the idiot proof way to go after all, albeit more work.

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    Re: Help - WB & Exposure when shifting

    For the WB issue I use the eye dropper tool to select a neutral point in both frames after LCC correction.

    For the centerfolding (tiling) issue I switched from the IQ260 to the IQ250.

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    Re: Help - WB & Exposure when shifting

    Quote Originally Posted by jagsiva View Post
    Thanks Christian.

    What you described is exactly my workflow with the exception of the WB on LCC. You seem to be correcting annually, where I corrected in "Auto". Will give this a shot.

    The IQ180 is likely exacerbating this more when compared to the P20.

    It is sounding like I just need to live with this. Maybe WB card on every shot is the idiot proof way to go after all, albeit more work.
    Have you tried to make your LCC several times? And several times a white balance?

    I had some faults, too, before I had found my way in the software. Don't know why - but from one day it worked nearly perfect. And now I have a list of different 'ready sets' I can use.
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    Re: Help - WB & Exposure when shifting

    Quote Originally Posted by weinlamm View Post
    Have you tried to make your LCC several times? And several times a white balance?

    I had some faults, too, before I had found my way in the software. Don't know why - but from one day it worked nearly perfect. And now I have a list of different 'ready sets' I can use.
    No I have not. But the in-camera WB does get fooled sometimes.

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    Re: Help - WB & Exposure when shifting

    [QUOTE=voidshatter;626478]For the WB issue I use the eye dropper tool to select a neutral point in both frames after LCC correction./QUOTE]

    this would work assuming you have a neutral point in the frame. From a technical standpoint, however, this is no different from sampling off a grey card shot.

    Quote Originally Posted by voidshatter View Post
    or the centerfolding (tiling) issue I switched from the IQ260 to the IQ250.
    I don't think I'd be shifting the IQ250 by 30mm

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    Re: Help - WB & Exposure when shifting

    Quote Originally Posted by jagsiva View Post
    No I have not. But the in-camera WB does get fooled sometimes.


    You mean you have differences in your pictures even if you had fixed the WB? Ok. Perhaps this is the cause for your problems?
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    Re: Help - WB & Exposure when shifting

    Quote Originally Posted by weinlamm View Post


    You mean you have differences in your pictures even if you had fixed the WB? Ok. Perhaps this is the cause for your problems?
    Sorry, I may have mis-stated that. When I have the camera set to daylight, I do sometimes get a very bluish temp. I have not seen this if I set a custom temp.

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    Re: Help - WB & Exposure when shifting

    Quote Originally Posted by jagsiva View Post

    I don't think I'd be shifting the IQ250 by 30mm
    Why not? I have tested and the IQ250 can be shifted by 40mm on the 90HR-SW.

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    Re: Help - WB & Exposure when shifting

    Quote Originally Posted by voidshatter View Post
    Why not? I have tested and the IQ250 can be shifted by 40mm on the 90HR-SW.
    Sorry, my bad. I thought you'd had only taken it to 20mm.

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    Re: Help - WB & Exposure when shifting

    If you shift the 40mm to much past 15mm on a full frame you hit the hard image circle indicator. This makes a shift much past 18mm pretty worthless due to the indicator which creates a hard solid vignette. You should see it on the crop sensor of the IQ250 well before 30mm.

    Paul

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    Re: Help - WB & Exposure when shifting

    Quote Originally Posted by Paul2660 View Post
    If you shift the 40mm to much past 15mm on a full frame you hit the hard image circle indicator. This makes a shift much past 18mm pretty worthless due to the indicator which creates a hard solid vignette. You should see it on the crop sensor of the IQ250 well before 30mm.

    Paul
    Paul, I find that with the IQ180, 90mm IC (32HR, 40HR) allows me +/- 12mm, with another 3mm if I want to push it, on one axis.

    120mm IC (60XL, 90 HRSW) give me a safe +/- 25mm on one axis and another 5 more if I push it.

    The SK120ASPH with 150mm IC goes all the way to max movements I have with a RotaSlide, so about +/- 40mm.

    With tilt, everything gets reduced a little. The 70mm IC lenses (23/28) give very little, but still fine for tilt.

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