Question about white balance

imeyer

A little background.. most of my stuff is shot inside in dimly lit rooms or outside
at night. I use two flashes, one master set to 0 EV and one slave set to +1/3
EV. I've always just shot with the WB set to tungsten, but some of the images
looked strange to me. I purchased an expodisc today (why I waited this long,
I don't know) and have been trying to get the correct balance for my set up.
I fear I've been looking at it too long so I thought I'd get some outside eyes
to help me decide which looks most natural.

This is shot without the expodisc:
2350K
-10 Tint
http://farm3.static.flickr.com/2059/2177353696_4477c952d8_b.jpg

This is adjusted after getting a WB reading from the slave flash pointing at
the camera with the expodisc.
2550K
-7 Tint (I believe)
http://farm3.static.flickr.com/2142/2177350832_db15ed7237_b.jpg

They both look acceptable I guess.. I don't know.. my eyes are tired

Thanks in advance for your input.

- Ian

jfriend

imeyer wrote:

A little background.. most of my stuff is shot inside in dimly lit rooms or outside
at night. I use two flashes, one master set to 0 EV and one slave set to +1/3
EV. I've always just shot with the WB set to tungsten, but some of the images
looked strange to me. I purchased an expodisc today (why I waited this long,
I don't know) and have been trying to get the correct balance for my set up.
I fear I've been looking at it too long so I thought I'd get some outside eyes
to help me decide which looks most natural.

This is shot without the expodisc:
2350K
-10 Tint
http://farm3.static.flickr.com/2059/2177353696_4477c952d8_b.jpg

This is adjusted after getting a WB reading from the slave flash pointing at
the camera with the expodisc.
2550K
-7 Tint (I believe)
http://farm3.static.flickr.com/2142/2177350832_db15ed7237_b.jpg

They both look acceptable I guess.. I don't know.. my eyes are tired

Thanks in advance for your input.

- Ian

The second one seems significantly too yellow to me (not enough blue). If I look at the CMYK (SWOP2) values, I see yellow values almost double the magenta which is not what you would expect.

The first one seems slightly too cool (a little too much cyan) both according to the numbers and too my eye, but much closer than the first one.

imeyer

jfriend wrote:

The second one seems significantly too yellow to me (not enough blue). If I look at the CMYK (SWOP2) values, I see yellow values almost double the magenta which is not what you would expect.

The first one seems slightly too cool (a little too much cyan) both according to the numbers and too my eye, but much closer than the first one.

Interesting observations.. thanks! I will mess around with the expodisc and
see if I can't get this nailed down because it's driving me crazy.

Any other tips (related to the expodisc) are more than welcome!

jfriend

imeyer wrote:

A little background.. most of my stuff is shot inside in dimly lit rooms or outside
at night. I use two flashes, one master set to 0 EV and one slave set to +1/3
EV. I've always just shot with the WB set to tungsten, but some of the images
looked strange to me. I purchased an expodisc today (why I waited this long,
I don't know) and have been trying to get the correct balance for my set up.
I fear I've been looking at it too long so I thought I'd get some outside eyes
to help me decide which looks most natural.

This is shot without the expodisc:
2350K
-10 Tint
http://farm3.static.flickr.com/2059/2177353696_4477c952d8_b.jpg

This is adjusted after getting a WB reading from the slave flash pointing at
the camera with the expodisc.
2550K
-7 Tint (I believe)
http://farm3.static.flickr.com/2142/2177350832_db15ed7237_b.jpg

They both look acceptable I guess.. I don't know.. my eyes are tired

Thanks in advance for your input.

- Ian

This recent posting on dpreview suggests that Expodisc has problems in some light temperature ranges. Would you be better off using a gray card and setting a custom WB from a shot of the card in the full scene (with flash) that you would be shooting in?

imeyer

jfriend wrote:

This recent posting on dpreview suggests that Expodisc has problems in some light temperature ranges. Would you be better off using a gray card and setting a custom WB from a shot of the card in the full scene (with flash) that you would be shooting in?

Yeah, I actually read that the other day. I'll give the normal gray card a shot
and see if that helps. I think it's strange that the Nikon provided gels don't really
make the light look natural. Actually I guess it's not that strange.. rather I just
wish it weren't the case.

rwells

The first thing you need to make sure of, is that your WB is set to AWB when you take the ExpoDisk shot. Take the ExpoDisk shot pointing your camera at the light source. Set your camera to use the picture you just took as the Custom WB (whatever method that is with the type camera your shooting)

Now, your WB should be spot on.


If you have your WB set to anything other than AWB when you take the "ExpoDisk" shot, your gonna get some strange results.


Hope that helps...

imeyer

rwells wrote:

The first thing you need to make sure of, is that your WB is set to AWB when you take the ExpoDisk shot. Take the ExpoDisk shot pointing your camera at the light source. Set your camera to use the picture you just took as the Custom WB (whatever method that is with the type camera your shooting)

Now, your WB should be spot on.


If you have your WB set to anything other than AWB when you take the "ExpoDisk" shot, your gonna get some strange results.


Hope that helps...

Aha, I will give that a shot. I'm shooting with a 5d and a D3 and I was always
under the impression (at least in Nikonland) that you set it to the custom
white balance, hold the WB button until PRE flashes, take the shot and that
is what your WB will be set to, at which point you can save it to any of the
custom WB settings. Not so sure about the 5D but I'll figure that out too and
see what happens.

Thanks and I'll be sure to post if that works.

rwells

Don't know anything about the Nikon, but Canon, have the WB set to AWB as stated above. Take a shot with the ExpoDisk over your lens pointing at the light source. Now, go into the menu and select Custom WB. What you will see will be the last shot you took. (the ExpoDisk shot) Just press the OK button, then the camera will state to make sure you set your WB to Custom WB. (the bowtie) This is how the process works on a 30D, I'm not 100% positive that this is exactly the same process on the 5D. I'm confident your manual will explain it.


Do this and your all set...

Vickster

Great info
I am getting ready to purchase an expodisc as I will be shooting a wedding in the snow and this should really help with the WB issues. I just went to the expodisc site and watched a couple of tutorials and i too think you need to get a reading for settings first then take a shot in AWB using expodisc and use that to set the custom WB. Their site does offer some additional information:
https://www.expodisc.com/index.php

I'm excited to try this toy out and appreciate all the info ya'll have offered!

imeyer

rwells: You are correct for setting custom WB on a Canon.. works the same way on the 5D.

The method I posted for Nikon works on the D200, D3, D300.. probably the D1*, D2* as well. I think the D40/40x/80/70/70s are all done via a menu.
Don't quote me on that.

Okay, so after more fooling around, here's what I came up with after reading
WB from a subject and applying it to one of my images that are not corrected,
but it's RAW so it should be able to be tweaked.

http://farm3.static.flickr.com/2069/2179488888_30c393abfe_o.jpg

This is the original, as shot WB:
http://farm3.static.flickr.com/2037/2179489200_ba3b4987a4_o.jpg

The most recent tweak looks a lot better to me than any of the others. Thoughts? Am I being too obessive about this?

Thanks again!

rwells

imeyer wrote:

The most recent tweak looks a lot better to me than any of the others. Thoughts? Am I being too obsessive about this?

Thanks again!

I don't know about the obsessive part, but as to the image; You've got some mixed lighting/WB issues with this shot. The lady on the left of picture, her cheek has a gangrene tint as does the lady on the right, under her earing. Other parts of the image have different WB colorations.

Unless you are very advanced at PS, I'd say your just not going to fix this image 100%.

imeyer

rwells wrote:

I don't know about the obsessive part, but as to the image; You've got some mixed lighting/WB issues with this shot. The lady on the left of picture, her cheek has a gangrene tint as does the lady on the right, under her earing. Other parts of the image have different WB colorations.

Unless you are very advanced at PS, I'd say your just not going to fix this image 100%.

Yeah, it's strange because both flashes have the same CTO filter over the flashes
and that was 90% of the light. Oh well.. I might take them off and just deal
with the discrepancies in balance.

Thanks, as always.

jfriend

rwells wrote:

I don't know about the obsessive part, but as to the image; You've got some mixed lighting/WB issues with this shot. The lady on the left of picture, her cheek has a gangrene tint as does the lady on the right, under her earing. Other parts of the image have different WB colorations.

Unless you are very advanced at PS, I'd say your just not going to fix this image 100%.

I also noticed that the skin tone colors on the lady to the left was a bit different than the lady on the right. I wondered if there was some mixed lighting going on. A rough mask could probably be used to tweak one independent of the other if one was really trying to fix this.

LiquidAir

The CTO gel I have been using has more magenta in it than most tungsten bulbs. If you WB for the gel, the ambient can end up looking a bit greenish. If I have to choose, I often WB for the ambient rather than the gel and fix the magenta casts where necessary.

I just picked up a CTS (Color Temperature Straw) gel and it is better on the green-magenta scale, but not strong enough to correct all of the yellow. Even so, the CTS gel usually gives a better end result: tungsten still looks yellowish, but not the deep orange you get with a daylight WB.

imeyer

jfriend wrote:

I also noticed that the skin tone colors on the lady to the left was a bit different than the lady on the right. I wondered if there was some mixed lighting going on. A rough mask could probably be used to tweak one independent of the other if one was really trying to fix this.

I'm actually trying to fix it for future shots more than anything else. I have
a couple of different custom WB saved that I'm gonna try out this weekend.

I've seen that Dave Black does the same CTO gelling that I do (using the
gels that come with the Nikon SB-800) and his images look fine.. that might
actually be a good place to start now that I think about it.

Okay, I'm really gonna stop worrying about this now. I've better things to
obsess over, really. Thanks for all the input everyone. Quite a pleasant
forum, this is.

LiquidAir: I will look into a CTS.. thanks!

Icebear

Not trying to be a terminology weenie here, but the problem y'all are discussing isn't one of "mixed lighting" which is easy to fix using custom WB, but of "unmixed lighting" where the kelvin is different on one part of the subject than on another. Damn near impossible to gell for unless you can use snoots or gobos.

jfriend

Icebear wrote:

Not trying to be a terminology weenie here, but the problem y'all are discussing isn't one of "mixed lighting" which is easy to fix using custom WB, but of "unmixed lighting" where the kelvin is different on one part of the subject than on another. Damn near impossible to gell for unless you can use snoots or gobos.

Interesting. I call something "mixed lighting" when different parts of the scene are lit by different types of lights. I've never seen it used the way you describe.

Regardless of terminology, it appears that there was different lighting on each of the women.

imeyer

Icebear wrote:

Not trying to be a terminology weenie here, but the problem y'all are discussing isn't one of "mixed lighting" which is easy to fix using custom WB, but of "unmixed lighting" where the kelvin is different on one part of the subject than on another. Damn near impossible to gell for unless you can use snoots or gobos.

Fair enough. The one thing I'm still scratching my head over is the only lights
illuminating the subjects are my gelled flashes.

imeyer

Oh, just for explanations sake.. I have the master flash firing at the subject
with the diffuser head on, and the slave with an Omnibounce held above and
left of the subject. Both are gelled with CTO gels. I like the technique so I
guess maybe the omnibounce is causing the shift? But that doesn't make sense
because it's white. Am I missing something here?

jfriend

imeyer wrote:

Oh, just for explanations sake.. I have the master flash firing at the subject
with the diffuser head on, and the slave with an Omnibounce held above and
left of the subject. Both are gelled with CTO gels. I like the technique so I
guess maybe the omnibounce is causing the shift? But that doesn't make sense
because it's white. Am I missing something here?

The possible explanations I can think of are:

1. There was enough non-uniform ambient light relative to your flash power to contribute to a light color shift
2. The Omnibounce has some sort of color bias
3. One of the gels wasn't fully into place
4. One of the flashes was contributing bounced light more than the other and the bounced light picked up a color bias from the surface it was bouncing off of

Icebear

jfriend wrote:

Interesting. I call something "mixed lighting" when different parts of the scene are lit by different types of lights. I've never seen it used the way you describe.

Regardless of terminology, it appears that there was different lighting on each of the women.

As much as I'd like to claim authorship, I can't. But my use of the terminology IS correct.

Any time there is more than a single source of light on a subject, you have "mixed lighting". The lighting sources "mix" with each other and give you a different kelvin than either by itself. "Unmixed lighting" results when the different light sources strike different areas of the subject without blending. I strongly urge everyone to buy, or at least check out from your library, Light - Science & Magic by Hunter, Biver & Fuqua. It really is the definitive text.

OffTopic

Icebear wrote:

As much as I'd like to claim authorship, I can't. But my use of the terminology IS correct.

Any time there is more than a single source of light on a subject, you have "mixed lighting". The lighting sources "mix" with each other and give you a different kelvin than either by itself. "Unmixed lighting" results when the different light sources strike different areas of the subject without blending. I strongly urge everyone to buy, or at least check out from your library, Light - Science & Magic by Hunter, Biver & Fuqua. It really is the definitive text.

I would refer you to page 292 of the third edition. The exact terminology of what you are referring to is called mixed color lighting.

jfriend

OffTopic wrote:

I would refer you to page 292 of the third edition. The exact terminology of what you are referring to is called mixed color lighting.

You got me curious about whether there is an official definition of "mixed lighting". I've come to the conclusion that there is not - that it's used in several in different ways. I happen to be used to how the term "mixed lighting" is used in this article about how to deal with it in Aperture and this article on white balance on Cambridge in Colour and this article by Digital Darrel and this scan of a few pages from The Complete Guide to Light and Lighting in Digital Photography. I'm not trying to argue that "mixed lighting" has to mean multiple light sources each lighting up different parts of the scene and that's the only thing it can mean, just that many people use it that way.

Icebear

OffTopic wrote:

I would refer you to page 292 of the third edition. The exact terminology of what you are referring to is called mixed color lighting.

Well sure. That's what we're discussing. Mixed or unmixed color temperatures. I'm just saying two things. First, terminology matters. It prevents ambiguity. Second, It's generally unmixed color lighting that causes us to tear our hair out, because when we get it right in one part of the image, it's wrong in another. Evenly mixed color lighting is not a problem for us.

Icebear

jfriend wrote:

You got me curious about whether there is an official definition of "mixed lighting". I've come to the conclusion that there is not - that it's used in several in different ways. I happen to be used to how the term "mixed lighting" is used in this article about how to deal with it in Aperture and this article on white balance on Cambridge in Colour and this article by Digital Darrel and this scan of a few pages from The Complete Guide to Light and Lighting in Digital Photography. I'm not trying to argue that "mixed lighting" has to mean multiple light sources each lighting up different parts of the scene and that's the only thing it can mean, just that many people use it that way.

Interesting articles, that illustrate the ambiguity I try to avoid. Perhaps we should introduce the concept of blended light when dealing with the issue of whether color temperature is similar across an image or not. Whatever. Y'all say potatoe, I'll say potatoe.

imeyer

This is pretty funny.. I was taking apart the omnibounce and inside was a silver
reflector attached.. I took it off and it fixed the odd colors for the most part.
Still need to get a proper WB setting, but yeah.

pathfinder

It is unfortunate that the use of 'mixed lighting" does not seem to be uniform.

It is frequently used to describe images with two or more light sources that affect different parts of an image differently - say a blue tint in the shadows, and a warmer, tungsten color in the highlights. There is no way for a single choice of Kelvin temperature will correct both areas at the same time.

On the other hand, if three separate light sources of three different temps Kelvin, are throroughly mixed equally all over the frame of the image, then there should be a single Kelvin temp that will match the results. "Mixed lighting" again.

But Icebear is correct too...

Page 292 of "Light- Science & Magic" does refer to mixed lighting as lighting that is mixed before hitting the subject ( say bouncing off a wall) such that a new color temp is needed to balance the image, but there is uniform color across then entire image.

They use the term "unmixed color" to describe images with different color of light - say strobe and tungsten - illuminating different parts of the image such that no single filter or gel will correct the image on film and no single Temp Kelvin will correct all the image in digital processing.

"No white balance will correct unmixed colors" directly from page 296.

Icebear

Sometimes the only solution that comes close to working is to gel strobes to match the predominant source and just overpower the "lesser." I've never been very happy with the results. I've found, with architectural photography, that your best technique in that situation is to educate your client before you even start shooting. It's called managing their (and my own) expectations.

LiquidAir

Icebear wrote:

Sometimes the only solution that comes close to working is to gel strobes to match the predominant source and just overpower the "lesser." I've never been very happy with the results. I've found, with architectural photography, that your best technique in that situation is to educate your client before you even start shooting. It's called managing their (and my own) expectations.

I have not been consistanly happy with gelling to match either. The gels usually don't match well enough and I still end up with color casts. One option is to bring more light and overpower the ambient. I will often turn off the more powerful ambient lights so I don't have to worry about them introducing casts. There is another option I am looking into which is to replace some of the ambient light with these screw in slave strobes:

http://www.bhphotovideo.com/c/product/89950-REG/Morris_11160_AC_Bare_Bulb_Screw_In.html

Just pull the incandescent or CFL out and temporarly pop a strobe in to take its place.

pathfinder

That screw in 100V slave strobe is kind of interesting. A guide # of 26 is certainly not going to overpower your main strobe, and a pair of them are less than $100.

The Strobist blog sometimes refers to the fluorescent light OFF switch, as the appropriate gel for overwhelming fluorescent light.


Sunpak makes a little flat panel flash - the FP-38 - with a guide # of 36, that also comes with a built in optical slave trigger. It is AA battery powered, and retails at B&H for $74.95. It will fit in some flat areas that a round bulb might not work - it is 6.3 x 6.3x 1 inch in size.