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Custom white balance (sample pics)

PostPosted: Wed Jul 13, 2005 9:32 am
by ElRonno
Good evening! (It's midnight on this side of the planet)

I'm still playing with my brand new toy. I just tried to see what difference custom white balance would make compared to the preset white balance for flash. For these I've used an SB-28 with homemade softbox. Now that homemade bit, involving printing paper, must throw some colour cast or another so let's see what happens.

ImageImage

Preset on the left, custom on the right, measured against an official 18% grey card. Although my screen is not calibrated (I am using the right profiles, but never actualy measured or changed any setting in that respect) I can clearly see an enormous improvement! :D

Too bad I can't save a custom white balance. :cry:

PostPosted: Wed Jul 13, 2005 9:36 am
by kipper
You can afaik.

PostPosted: Wed Jul 13, 2005 9:43 am
by ElRonno
According to the manual: "The camera can store only one value for preset white balance at a time; the existing value is overwritten when a new value is measured or copied."

So I can't make a custom white balance settings list. That would allow me to calibrate and save each flashlight's white balance.

PostPosted: Wed Jul 13, 2005 9:48 am
by birddog114
ElRonno wrote:According to the manual: "The camera can store only one value for preset white balance at a time; the existing value is overwritten when a new value is measured or copied."

So I can't make a custom white balance settings list. That would allow me to calibrate and save each flashlight's white balance.


Yes, it's correct, only one preset WB at one time, the D2 can do more.

Custom or preset WB on the D70 or D100 is only for one setting not in multiple or difference WB settings.

PostPosted: Wed Jul 13, 2005 10:15 am
by gstark
ElRonno wrote:So I can't make a custom white balance settings list. That would allow me to calibrate and save each flashlight's white balance.


Given that WB is somewhat of a "live" setting, depenadant upon the actual conditions at the time of shooting, this is probably not too bad a thing.

If you're doing a lot of studio work, having stored wb settings for the studio setups that you commonly use would be fine, but beyond that, for normal day to day shooting, I'm not sure that they would have great value.

PostPosted: Wed Jul 13, 2005 10:56 am
by hangdog
What if you take various low-res pictures (to save card space) under different white balance conditions (for different room or studio conditions that you'll repeatedly use), lock the pictures on your CF card(s) and refer to them for later use?

[Edit] To clarify, you could just photograph labels that say "Flashlight A" or "Studio Portrait B", and use those for quick switching of custom WB settings.

--Chuan

PostPosted: Wed Jul 13, 2005 11:01 am
by birddog114
hangdog wrote:What if you take various low-res pictures (to save card space) under different white balance conditions (for different room or studio conditions that you'll repeatedly use), lock the pictures on your CF card(s) and refer to them for later use?

--Chuan


The only preset wb you can play with ease when you shoot in NEF.
If you have the photos saved on the CF card and review on your camera LCD for the WB reference, what factor can tell you what/ how/ why WB was set previously? You need to view it on the computer mon.

PostPosted: Wed Jul 13, 2005 11:15 am
by hangdog
Sorry Birddog, I must've been editing my post while you were typing. Photos of labels should remove the guesswork, I think.

It's pretty much what a few models of compact digicams do, only you can probably name the custom settings instead of photographing labels, and the compacts' custom settings are stored in internal memory instead of a removable card…

--Chuan

PostPosted: Wed Jul 13, 2005 11:27 am
by birddog114
hangdog wrote:It's pretty much what a few models of compact digicams do, only you can probably name the custom settings instead of photographing labels, and the compacts' custom settings are stored in internal memory instead of a removable card…

--Chuan


It's P&S not with the DSLR :wink:

PostPosted: Wed Jul 13, 2005 11:31 am
by gstark
hangdog wrote:What if you take various low-res pictures (to save card space) under different white balance conditions (for different room or studio conditions that you'll repeatedly use), lock the pictures on your CF card(s) and refer to them for later use?

[Edit] To clarify, you could just photograph labels that say "Flashlight A" or "Studio Portrait B", and use those for quick switching of custom WB settings.

--Chuan


I'm not entirely sure of the purpose of this. On the D70, you can't (to my knowledge) load a wb setting in the way that you can load a custom curve.

Once you have taken a custom wb setting, you can leave that wb setting in place, until you overwrite it with another, but overwriting it only puts a newly created one in its stead.

PostPosted: Wed Jul 13, 2005 11:45 am
by robboh
ElRonno,

What sort of background did you use for this and how far from the background was the bottle?? Im just curious as its a very nice shade of blue coming down to a grey at the front (flash strength v's distance causing this??).

As for if its 'better' or not, I guess that depends on what the original setup looks like and how accurately you feel the colours are portrayed in the custom v's the pre-set. But yes, I personally prefer the look of the custom.

IIRC, you can set up a custom WB off a photograph. Therefore, you could possibly have several greycard photos in different lighting stored on your card and then use those to measure off.

PostPosted: Wed Jul 13, 2005 11:51 am
by birddog114
robboh wrote:IIRC, you can set up a custom WB off a photograph. Therefore, you could possibly have several greycard photos in different lighting stored on your card and then use those to measure off.


Then how do you upload the preset wb into the camera? and in one shooting event with various of lighting conditions?

The preset WB can be done on the spot easy with few method and parts as:
Pringle lid, expodisc, Ezybalance etc...

PostPosted: Wed Jul 13, 2005 12:09 pm
by robboh
Birddog114 wrote:Then how do you upload the preset wb into the camera? and in one shooting event with various of lighting conditions?
The preset WB can be done on the spot easy with few method and parts as: Pringle lid, expodisc, Ezybalance etc...

Agreed, not something I would bother with. Must get hold of one of these whitebalance tools and have a play. I think Pringles lids are transparent over here though, so would have to get an ExpoDisk.

As for reading off a photograph of a greycard, I can really only see this of being use in a studio under controlled lighting (which Im presuming is what ElRonno wants to do?). Though if you are doing a panorama it could be useful. Take your first pic and then use this to preset the WB for the rest of the panorama group.

As for the 'how'. See pages 54-55 of the manual:

Also, from page 52:

Preset White Balance
Preset white balance is used to record and recall custom white balance settings for shooting under mixed lighting, to compensate for light sources with a strong color cast, or to replicate the white balance used in an existing photo. Two methods are available for setting preset white balance:

Measure white balance
Neutral gray or white object is placed under lighting that will be used
in final photograph and white balance is measured by camera.

Copy from existing photograph
White balance value is copied from photo taken with D70 (if desired,
source picture can be RAW image modified using white balance adjustment option in Nikon Capture 4 version 4.1 or later).

The camera can store only one value for preset white balance at a time; the existing value is overwritten when a new value is measured or copied. Measuring a new value for white balance automatically sets Preset to Measure.[/list]

PostPosted: Wed Jul 13, 2005 12:18 pm
by birddog114
Has anyone did copy a preset wb value stored from the CF card (inserted inside the D70) direct to the D70? not via any other means.

PostPosted: Wed Jul 13, 2005 12:19 pm
by hangdog
robboh wrote:<snip>Copy from existing photograph
White balance value is copied from photo taken with D70 (if desired,
source picture can be RAW image modified using white balance adjustment option in Nikon Capture 4 version 4.1 or later).

The camera can store only one value for preset white balance at a time; the existing value is overwritten when a new value is measured or copied. Measuring a new value for white balance automatically sets Preset to Measure.


Yep, that's what I meant to say, in my own clumsy way. :D

--Chuan

PostPosted: Wed Jul 13, 2005 12:25 pm
by birddog114
And then the value of preset WB of the photos you took this morning is difference with the photos you're taking one hour after in the opening space with natural lighting.
How do you know the correct value which you may playing with compensation of the value in between the two, it requires times for you to achieve all off task prior to shoot, while on the other side with tools, just 30 second and you're ready to shoot.
These applied to studio shooting as well with difference backdrop, lighting source or lighting direction and subjects.

PostPosted: Wed Jul 13, 2005 12:35 pm
by birddog114
In seriously shooting.
Even with the D2 series, I don't store or save the preset WB in the camera, I want to have the "real" preset wb which I'm going to shoot in a few second or use the light meter.
I don't trust my eye, neither the light meter built in the camera.

PostPosted: Wed Jul 13, 2005 4:00 pm
by robboh
I fully agree with you Birdy :)
Light temperature is way too variable outside to think of using pre-prepared pics. And yes, I cant really see the point in a studio either, especially if you have other tools that you can use (eg ExpoDisk).
On the other hand, the option is there if ElRonno wants to play with it and he did ask if he could store multiple custom-WB's.

PostPosted: Wed Jul 13, 2005 7:36 pm
by ElRonno
gstark wrote:Given that WB is somewhat of a "live" setting, depenadant upon the actual conditions at the time of shooting, this is probably not too bad a thing.

If you're doing a lot of studio work, having stored wb settings for the studio setups that you commonly use would be fine, but beyond that, for normal day to day shooting, I'm not sure that they would have great value.


I was indeed referring to studio work! Outside the controlled environment the color temperature varies so much that saved white balance settings are indeed useless.

PostPosted: Wed Jul 13, 2005 7:41 pm
by birddog114
Studio works! Expodisc or light meter are the tool of trade.

PostPosted: Wed Jul 13, 2005 7:44 pm
by ElRonno
hangdog wrote:What if you take various low-res pictures (to save card space) under different white balance conditions (for different room or studio conditions that you'll repeatedly use), lock the pictures on your CF card(s) and refer to them for later use?


Good idea! But I wonder how that "re-use white balance from other picture" works. Does it store the white balance data in EXIF somewhere, or does it calculate a white balance from that other picture?

If the white balance is stored in numbers somewhere, then I can write the numbers down on the flash units that I use and batch process the RAW files afterwards to correct the white balance based on which flash I used.

PostPosted: Wed Jul 13, 2005 7:51 pm
by birddog114
ElRonno wrote:
hangdog wrote:What if you take various low-res pictures (to save card space) under different white balance conditions (for different room or studio conditions that you'll repeatedly use), lock the pictures on your CF card(s) and refer to them for later use?


Good idea! But I wonder how that "re-use white balance from other picture" works. Does it store the white balance data in EXIF somewhere, or does it calculate a white balance from that other picture?

If the white balance is stored in numbers somewhere, then I can write the numbers down on the flash units that I use and batch process the RAW files afterwards to correct the white balance based on which flash I used.


That what was my answer to handog and robboh in previously posts.

PostPosted: Wed Jul 13, 2005 8:01 pm
by ElRonno
robboh wrote:What sort of background did you use for this and how far from the background was the bottle?? Im just curious as its a very nice shade of blue coming down to a grey at the front (flash strength v's distance causing this??).


No nifty lighting tricks here, it's just a graduated white/blue 0.8x1.08 m background!

PostPosted: Thu Jul 14, 2005 7:22 pm
by robboh
ElRonno wrote:
robboh wrote:What sort of background did you use for this and how far from the background was the bottle?? Im just curious as its a very nice shade of blue coming down to a grey at the front (flash strength v's distance causing this??).

No nifty lighting tricks here, it's just a graduated white/blue 0.8x1.08 m background!

Kewl. Thanks for that.
Not sure about where the WB is stored. It must be stored in the pic somehow or else how would Capture be able to tell what WB was set. Loading it up in ACR will give you the As-Shot Tint/Temp. Not sure if you can actually see what tempK or tints were chosen in NC??

PostPosted: Thu Jul 14, 2005 8:14 pm
by Hlop
Birddog114 wrote:Studio works! Expodisc or light meter are the tool of trade.


Speaking of Expodisc .... Yeah, I know we already discussed it but I didn't really get it ... So, how does it work? If I understood it correctly, I have to point it to the light source and set custom WB. Yeah, this is clear. But what do I do if there are different light sources? Say, big hall with tungsteen, fluorescent lamps and some daylight through the windows?

PostPosted: Thu Jul 14, 2005 8:18 pm
by birddog114
Hlop wrote:
Birddog114 wrote:Studio works! Expodisc or light meter are the tool of trade.


Speaking of Expodisc .... Yeah, I know we already discussedc it but I didn't really get it ... So, how does it work? If I understood it correctly, I have to point it to the light source and set custom WB. Yeah, this is clear. But wht do I do if there are different light sources? Say, big hall with tungsteen, fluorescent lamps and some daylight through the windows?


What you should do is aim your camera with the lens and Expodisc mounted on the lens to the light sources and do the preset WB.
Normally in a hall like you mentioned, the light sources will mixed and depend on where's your subject is, diference corner with difference light source, you may re do it if you want to be sure.

PostPosted: Thu Jul 14, 2005 8:25 pm
by Hlop
Birddog114 wrote:What you should do is aim your camera with the lens and Expodisc mounted on the lens to the light sources and do the preset WB.
Normally in a hall like you mentioned, the light sources will mixed and depend on where's your subject is, diference corner with difference light source, you may re do it if you want to be sure.


Thanks Birddog, this is fair enough

Will it work if I'll point it to the subject and set custom WB or it MUST be pointed to the light source?

PostPosted: Thu Jul 14, 2005 8:30 pm
by birddog114
Hlop wrote:
Birddog114 wrote:What you should do is aim your camera with the lens and Expodisc mounted on the lens to the light sources and do the preset WB.
Normally in a hall like you mentioned, the light sources will mixed and depend on where's your subject is, diference corner with difference light source, you may re do it if you want to be sure.


Thanks Birddog, this is fair enough

Will it work if I'll point it to the subject and set custom WB or it MUST be pointed to the light source?


Can be done on both ways if you want to get the correct wb of the surrounded light sources of the subject.