Problem with Set Gray Point?

Discussion in 'Nikon Capture and View NX' started by jgatscher, Jul 29, 2008.

  1. jgatscher

    jgatscher

    19
    Jul 29, 2008
    Nashville
    I'm having some problems when trying to use a custom WB adjustment using NX2. I was wondering if anybody could review my steps and tell me where I have gone astray. Any help would be greatly appreciated.

    Open NEF with gray card in the photo
    Go to WB and select Set Gray Point
    Select Marquee Sample
    Click start and window in gray card area
    Highlight the WB adjustment step
    Click in the batch icon and Copy Adjustment
    Go to browser and select NEFs that want to apply the new WB to
    Click in the batch icon (bottom left) and select Paste Adjustment
    Choose Replace current settings
    Start batch process by saving over NEFs

    When I open the modified NEFs with new WB settings, I get a WB setting that is completely different than what I had obtained from the gray card. I have no idea what I'm doing wrong. The WB result is completely different Red and Blue numbers??

    Jeff
     
  2. Jeff, I'm not at my computer that has NX so I can't check every single step but your process looks fundamentally correct.

    Try affecting just one new file rather than batch processing. To do that, copy the WB in the source file. Open a new file. Paste the adjustment. If that produces inaccurate results, I have no idea what's going wrong. If that simple process is indeed yielding inaccurate results, I would consider downloading NX and re-installing it.
     
  3. bh626

    bh626

    280
    Mar 6, 2006
    Ontario
    I just tested this. Here's how it worked for me.

    I opened pic 1, chose set Gray point using a Marquee.
    Drew the marquee - Red=1.11, Blue=1.01
    Hilited the WB step, right clicked and "Copy Adjustments"
    Right clicked 6 other pics in the browser and "Paste Adjustments"
    Selected option to "Replace Current Settings"
    Opened other pics - most WB Red/blue was the same as pic 1, a couple were off a bit; eg: 1.12/1.02 - strange...
     
  4. I wonder if the actual WB is actually exactly the same and the way it reads the numeric values differs slightly. With such small variation in values, I would venture to say that it's not possible to see any difference.
     
  5. jgatscher

    jgatscher

    19
    Jul 29, 2008
    Nashville
    I tried this.

    Open up 3 NEFs from 3 different Nikons (D50, D70, D80). I used the D70 to set WB using gray card. Coppied the WB adjustment step. Then went to the D80 NEF and pasted into it. Got crazy WB numbers. Did the same into a D50 NEF and again got crazy WB numbers. So then I opened up a different D70 NEF and pasted into that one. This time the WB numbers were identical to the original D70 that had the gray card.

    I would not of guessed it, but there must be something different in the way WB is handled by the other cameras? Can any one else test this out using two different Nikon cameras?

    Jeff
     

  6. That is really bizarre. If two people are shooting the same scene using two different camera models but one person is post-processing all of the files, that person would have to use different sets of WB data. I don't get it.
     

  7. Tom, I'm very confused. If it only works on one picture, it would only work on the picture that contains the grey card. We're not communicating well, so please run that by us again.
     

  8. Tom, I've got to agree with you to the extent that repeatable, exactly equal results will not be rendered. However, the goal is not to achieve exactly equal results; the goal is to achieve practical results that present the same fundamental white balance to the eye.

    My point was that if a WB step of 90 red and 110 blue is copied and pasted into another image, I thought those same settings would be pasted even if that meant that the resulting WB would be wrong for the particular image. I now realize that I was wrong. Copying and pasting does not produce the same settings unless everything remains unchanged as you mentioned.

    When Jeff reported that the WB that he copied into images taken with different cameras rendered very different settings, I now realize that that didn't have anything to do with the fact that each image was taken with a different camera. Instead, the issue is that he copied the settings and pasted them into apparently completely different images, incorrectly expecting as did I that the red and blue settings would remain constant.

    This has been very informative!
     
  9. jgatscher

    jgatscher

    19
    Jul 29, 2008
    Nashville
    The problem that I have is that my application is in a studio shoot. I use two cameras both set-up identical and on full manual (D50 with a 50mm prime and D80 with a wide angle zoom). The lights are also set-up and have been properly metered using a light meter. Everything is ready to start shooting.

    In the past I would grab the D50 and have the model hold a gray card for the first couple shots and then just start shooting using both cameras. Again, the lighting is not changing at all and the model is positioned with only a small area to physically move around in. What I discovered last night is that if I take the D50 NEF with gray card and set my gray point based on that image I get say Red 1.07 and Blue 0.89. Now if I paste that setting into every other D50 NEF that was shot during this session (lights not changing), I get what I expected...every D50 NEF now has WB with Red 1.07 and Blue 0.89. Not slight variations of this WB but the exact numbers.

    But if I paste this WB into the D80 NEFs that were shot under the same lighting conditions, I get different WB results and not just slight deviations...but very noticeable WB problems.

    So my quandary is trying to understand why the differences between very similar shots but shot with different Nikon cameras?

    I know what my solution is...just take a gray card photo with each camera and apply post processing to each set of NEF based on camera model....but still, why different?
     
  10. Hi,

    Just did a quick comparison between nx and nx2 (same NEF's same white point).
    Result NX worked as expected NX2 did not.
    So, with regard to above posts, either NX2 is doing the right thing or NX is. My vote is for NX on this one. That is the expected behaviour, that is why we make a test shot that includes a gray card. Therefore I believe that there is a problem.
     
  11. Tom, I'm not sure I agree with your statements. Certainly if you move a camera so much as an inch and wait a few minutes for the sun to move a few seconds in rotation or focus on a different subject conditions do change; but only microscopically to be sure. By your own argument essentially nothing then could be batched because the light conditions and actual subject you're shooting will vary voiding the color, saturation settings etc. from one shot to the other. If the WB varies that much surely everything else upon which it is based are also changed. Further I've never hear that the gray card must be a substantial part of the image, even from the manufacturers of the cards.

    White balance has never been discussed in terms of "precision" but rather of the prevailing light conditions under which one is shooting. Of course if you're out on a sunny day and pass through a wooded area in the shade, the WB changes, but quickly walking back into the sunlight should return the gray card based WB setting to a reasonably useful value.

    This suggests that gray card (or WhiBal card in my case) for setting WB is essentially useless for casual shooting and implies that simply setting the camera to AWB might even be better...and my experience definitely does NOT agree with relying on AWB over calibrating against even gray objects in the image itself.

    Would you cite some source for what you describe?
     
  12. Jeff, I just noticed that your first few posts here at the Cafe are in this thread. David, your first post is also here. Welcome to both of you!

    Jeff, now that I understand the situation you are describing, that is completely baffling to me. You're right of course that one solution is to simply use a grey card with each camera, but that really is a solution for which there should never have been a problem in the first place. Considering David's findings, please let us know whether the results you reported were noticed when using NX, NX2 or both.

    David, if others of us can replicate your findings that NX and NX2 are producing different results, you have appeared to have discovered a bug if I understand everything properly. When I get a moment, probably this weekend, I will compare results when copying a white balance setting of the same scene taken by a CP5700 and a D80. Unfortunately, just a couple days ago I uninstalled NX from my computer, so I'll be using only NX2. However, I am happy to send the files to anyone who still has NX on their computer.
     
  13. mphillips

    mphillips

    32
    Jul 8, 2008
    South Africa
    Hi All

    Just to clarify.

    This "variance"only occurs pasting white balance card readings across cameras ?

    If you do it for a number of images from the same camera do you get the same variances ?

    I ask because I use a Whibal card and regularly used the "paste adjustment" in CNX1 with good results but haven't tried in CNX2 yet.

    Regards

    MikeP
     
  14. Tom,

    I'm not sure your point is addressing the questions. As I understand it you are saying that WB can vary shot to shot, so batching WB will give wrong results.

    I use Whibal to set a custom WB, and have used that to paste the setting into other shots. Of course, the lighting may be different in other shots, but that just means the photo will have an inaccurate WB due to the light. Nevertheless, the actual WB VALUE copied and pasted should be the same, whether it accurately corrects the white balance.

    I understand from other threads that certain NX commands like "auto contrast" can't be batched because it requires taking a dynamic reading on each image, not pasting a value. Nor could you batch cloning out heads or sharpening eyes, etc.

    It does not make sense to me that you could not use a Whibal card to set WB and then copy/paste that into other photos. I look forward to hearing the results of more research on this.

    I still have NX and NX2 installed and will take a look after I get some work done....
     
  15. jgatscher

    jgatscher

    19
    Jul 29, 2008
    Nashville
    Thanks for the welcome Mike....It's great to find a NX user group...I've been using NX since June 2006 and haven't looked back...it's the best NEF converter period....if it only was a little faster...but I won't go there

    I also removed my NX and so only have NX2 running...

    I will try a different approach tonight by pasting a WB setting into the same camera NEFs but using photos that were shot with a different studio light setup...I'm curious to know if a fixed WB setting (like Red = 1.07 and Blue = 0.89) can be pasted into another NEF (from the same camera) that has different lighting and still remain R 1.07 & B 0.89....I don't have access to my NEFs right now so I will report back tomorrow
     
  16. I think we're all saying the same but varying a bit on degrees. I apologize for "sort of" hijacking the main idea since the OP asked about studio shooting with different cameras and I addressed outdoor shots. I'm generalizing that if the light characteristics and shooting environment remain roughly the same ("roughly" based on personal judgment) pasting WB settings obtained from a gray card in that environment in batch will yield accurate images.

    I appreciate and enjoy the open discussion and exchange of ideas here. That is why I enjoy the Cafe so much.

    In a thread about using gray cards Philippe Roger commented that if you select AWB you cannot accurately use the card to set white balance. I hope he sees this or that I can recall the post. It would be a valuable point in this discussion.

    I found it!

     
  17. Thans for the hijack Rich as this last comment makes the most sense to me. Now I don't use any graycards or expodiscs but I intend to get one in the near future. This will probably reduce the number of future headaches :biggrin:
     
  18. mphillips

    mphillips

    32
    Jul 8, 2008
    South Africa
    Thanks Rich

    That makes sense !

    Regards

    MikeP
     
  19. Hi,
    Thanks for the welcome mike
    I retract my earlier statement that nx behaves as expected and nx2 does not.
    I decided to do some more tests in nx first with the photo's from my earlier test and then with other shots. What had come up to my expectations, in nx, before I went out to eat was now the same as in nx2: different multipliers from the saved multipliers when these settings were loaded. Note between the two tests and whilst in nx, my pc froze up and I had to restart also I had not used nx since nx2 came out. Futher tests revealed that, as others have stated, it depends on the recorded white balance as to whether it works or not. So far all shots recorded direct sunlight w.bal give the same multipliers. auto gives different multipliers.

    It may have been a fluke, but I am certain that nx gave the same multipliers even on auto w.bal shots in my first tests.
    Anyhow I thought that one of the joys of shooting raw was that one can alter the white balance after the event irrespective of the recorded values and that the raw information was the same?


    Take care.
     
  20. jgatscher

    jgatscher

    19
    Jul 29, 2008
    Nashville
    what if you open a file switch WB from recorded (which was auto) to sun then save it...and then paste in a WB adjustment from gray card...wonder if that would work...not at my pc so can't try now