Need help with obtaining UniWB for a Nikon D40

[Shane]

I have been using UniWB settings since about 2004 for all my digital cameras over the years (Nikon D70, D200, D300, D500, D700, D800, D810 and D850). I have never had a problem building the UniWB reference target from scratch on the computer.

 

A project i am working on requires the use of an unmodified Nikon D40 with a UniWB reference. I cannot get the D40 to capture a pre-WB shot of my target, which is often referred to as "wine" colour, being a reddish purple. No matter what I do, the D40 will not accept the captured image of the "wine" target as a WB. This is a standard procedure that has worked for every other Nikon I have owned for the past 16 years.

 

Has anyone here ever successfully produced a UniWB for the Nikon D40 and if so would you be prepared to provide a copy to me?

 

Thanks

[Andrea B.]

I've had that problem. I then lightened the magenta/wine target and got a WB. This causes possibly more iterations.

 

I'm looking for a link which might have a downloadable file. Stay tuned.

 

Added a few minutes later: http://www.guillermo...wb/index_en.htm

Guillermo has a downloadable D40 file. Go to the link and scroll down.

 

 

Side Note: I think Darktable (free, open source) can tell you what the RGB multipliers for iterations are if you don't want to use command line Dcraw.

[Shane]

Thanks Andrea, I had already been there but that is a 40D Canon UWB, not Nikon D40.

 

Did you have this trouble with a D40 or another model?

 

I already tried the "lightening " of the target, but didn't seem to help.

[Andrea B.]

Sorry about that! I did not pay attention to the extension. Red face.

 

I had the problem with another model but I don't remember which one.

 

Write to Iliah.

 

Added: Did you try the blowout method? Against bright light shoot exposure long enough to blow out all channels then check multipliers?

[Shane]

Time window is narrowing and I tried for many hours, so I am trying to reach out at several forums. I might try asking Illiah Borg if I can get hold of him. First person I contacted was our old friend Akira, since he had a D40, but unfortunately never used a UniWB for it.

[Shane]

Cross post :)

[Shane]

Shot an email of to Iliah but I know he's always very busy, however, he may have created one years ago.

[Shane]

Apparently, it's been so long that I had forgotten but I wrote this on this forum in the early years......

 

"It should also be noted that some cameras, Nikon D40 for instance, cannot be white balanced against vegetation when using a filter such as the 099 but work OK with stronger IR filters. This is because the 099 allows too much red in addition to IR. An exposure under these situations results in very weak signal in the blue and green channel (3-4 stops underexposed). In camera WB works using multipliers for the R, G and B channels and under the 099 conditions would require "unusual" values for the multipliers. While some cameras can handle this, the D40 cannot. Perhaps Nikon put limits on these values to "protect" the user from "mistakes". I have tried forcing the D40 to accept WB multipliers out of the "normal" range by uploading reference images but it will not accept them until I reach a point where my multipliers are the same as that found for Tungsten +3 in-camera WB option."

 

Although I never tried a UniWB for the D40 at that time, perhaps my own explanation answers my problem.

[Andrea B.]

There is so much on the forum now that I have started to forget what all is actually here.

 

So you are saying that the Nikon D40 will not go to complete unitary white balance?

What are the multipliers for Tungsten +3 (if you happen to have them handy)?

 

 

Did you ask Birna?

[Shane]

So you are saying that the Nikon D40 will not go to complete unitary white balance? It appears so but not definite yet.

What are the multipliers for Tungsten +3 (if you happen to have them handy)? I don't but I might be able to find them later when I habve a little more time.

I'm in a "good"weather/time crunch. Running a 1000 test shot matrix, multiple DSLRs, 3 lenses, 8 filters, ambient conditions etc. As the weather has been unpredictable, I've only done 85!

[Shane]

Did you ask Birna? I had hoped she might see the post.

[Andrea B.]

Did you look/search Flickr?

[Shane]

Thanks for that edit by the way......saved me It was habit.

[Andrea B.]

((No problem-o.))

 

Birna wrote me that she did not have a D40 UniWB file.

 

I've looked around a bit. But you know the same places I know.

I'm beginning to think that that a UniWB file cannot be made for Nikon D40.

 

Sometimes Iliah or Lexa or the other people answer very quickly if you ask questions on the Raw Digger site. Or maybe the Raw Fast Viewer site.

[Andrea B.]

Shane, do you have to shoot the photo in UniWB?? Couldn't you just make the photo in some other WB and then convert it to UniWB in DarkTable or in RawDigger??

 

DarkTable permits you to directly set WB multipliers. RawDigger has certain settings which allow you to export a Raw Composite with 1,1,1,1. With either one you would have to save as a TIF. A TIF file is kinda, sorta almost raw.

[Shane]

Iliah has already responded and correspondence is ongoing.

 

I want the UWB in camera so I can much more accurately capture the exposure required ( keep in mind I'm using 7 different cameras in sequence so it makes that easier).

 

Although this is a posat camera issue...I had tried Darktable a little while ago but noticed an issue....

If I import a nef file and change the WB numbers to 1, then I export the image as a jpg, why doesn’t it update the WB exif data in the jpg file to reflect the new WB multipliers? The jpg image has certainly been affected my modification, it looks very green but the WB numbers are still identical to the original unmodified nef file.

[Andrea B.]

Well that's annoying about the DarkTable export.

 

Glad you heard from Iliah. If he doesn't know, then nobody does methinks.

 

Stop by later and show us some fotos !!