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Author Topic: White Balance Aids, Advice Please  (Read 5280 times)
Gary Ferguson
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« on: December 28, 2006, 07:50:33 AM »
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I'd like to take a more systematic and consistent approach to setting the white balance with a Phase One P25 back, and also Canon 5D and 1Ds MkII cameras. However, I'd appreciate some advice on the confusing range of white balance aids on the market. Here's some of my questions.

1. It seems like white balance aids fall into two categories, neutral cards that are included in a test shot and diffusion screens that fit over the lens. What are the advantages and pitfalls of each route?

2. With a diffusion screen, like the Expodisc, isn't the reading distorted by the subject? For example, imagine a portrait where the subject is wearing a red outfit, the subject then changes into a blue outfit but the lighting and composition remain exactly the same, wouldn't you get two dramatically different readings?

3. Does the diffusion screen supplied with Phase One backs do the same job without the hassle of removing lens hoods and screwing in filters?

4. Looking at the "warm" versions of the Expodiscs, isn't there a fixed adjustment that could be applied to the "normal" screen to get the same results?

5. The neutral cards seems to range from the Novoflex Zebra at 9.00 to the CBL card at 199.95. Why such a big price range and is it justified?

Thanks for your advice.
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Morgan_Moore
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« Reply #1 on: December 29, 2006, 04:24:48 PM »
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2. With a diffusion screen, like the Expodisc, isn't the reading distorted by the subject? For example, imagine a portrait where the subject is wearing a red outfit, the subject then changes into a blue outfit but the lighting and composition remain exactly the same, wouldn't you get two dramatically different readings?

[a href=\"index.php?act=findpost&pid=92616\"][{POST_SNAPBACK}][/a]

This is a thread Ive been thinking about for some time.

I think you are right about the expodisc - however it is quick to use - you cant always hand your subject a grey card - your subject may be a lion

Basically an expodisc will get you in the right ballpark very quickly if for instance you have floucenent source

THere seem to be two approaches to white balance

A ) shooting a product - you want the colour accurately reproduced even if for instance you are shooting the product under tungsten

B ) shooting a scene or an architecture pic at dawn - with a sunset you will want warm glows and and maybe very yellow light coming from internal tungesten rooms

In both cases using  a card or expo would seem to be heavily affected by the scene (say you are shooting a an interior with orange walls - the reflected oragne will hit your greycard and throw the room blue once you click on the card

For the b type approache probably you need to get a neutral setting for your camera maybe by photographing a grey card on a half cloudy day

Using that setting/parameter will make you tungstens yellow and sunsets gold


Another method that interests me is using a combination of a grey card (at the scene) and a colour temperature meter

So you click for grey and then dial in the appropriate coolness or warmth

Balancing the different cameras should work if you build a standard setting for each camera at the same time

A more complex method would be to shoot a gregtag card in a neutral light and build profiles for the cameras and then you have a standard setting

If you add light using flash or hot lights it then of course gets even harder - especially if thier temperature varies with power output

I think my prefered method would be to get a great gregtag image on a neutral day, get filters on my flashes until they match that and shoot away

I think there are so many variables that at the end of the day we always tweak the final image by eye anyway so over technicalisation probably aint worth the time

CUrrently I have a few profiles I have made basically grey day and elinchrom - I use those as a start point

I shot a (horses - dont hold grey cards and the steward enclosure was flouro) job  the other day 20-35 with the SLRn 80 on the blad and 300/28 an the D200 - getting a consistent look amounted to trial and error - if only I could just have had velvia in all of them !

I am also not convinced that an expodic is any better than the lid off an ice cream box which is cheaper and comes with free ice cream

THe expo/ice cream box will at least give you a similar start point between the different cameras


Good luck..

SMM
« Last Edit: December 29, 2006, 04:28:09 PM by Morgan_Moore » Logged

Sam Morgan Moore Cornwall
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hcubell
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« Reply #2 on: December 29, 2006, 04:47:55 PM »
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I also have been wondering about the efficacy of the Expodisc as an aid in setting White Balance in landscape photography where you are often shooting in the warm light of early morning and late in the day.  You obviously do not want to dial that out by setting your WB to "neutralize" the color of the light. I would be curious to hear about the techniques of others in setting WB in such settings. Is anything reliably better than just setting the WB on Auto and doing a custom reset in the raw converter?
Thanks.
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marc gerritsen
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« Reply #3 on: December 29, 2006, 06:48:40 PM »
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I have given up trying to set my wb in camera on the shoot. There are indeed too

many variable like warm afternoon light or the previously mentioned orange wall

or combination of inside/outside light. I like to do everything in my raw converter

and control the situation at the tail end with wb blending.

True white, black and grey are also very subjective. In some shoots a true white

wall might need a slight cooler tone and in others a warmer one, I guess the same

counts for landscape photography.

Marc
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Jonathan Wienke
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« Reply #4 on: December 29, 2006, 08:16:49 PM »
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I never bother with setting white balance manually in-camera while shooting. I might occasionally throw in my Color Checker for a reference, but unless I'm shooting products or need to match multiple cameras or something like that, I prefer to tweak WB manually in the RAW converter.

Using a WB reference for sunsets is almost pointless. You have a mix of the warm light from the sun, and very cool light from the sky, and the WB you get depends heavily on the exact angle of the WB reference card to the sun vs the sky, or the exact orientation of the camera if using a diffusion screen. Throw in the factor of the light changing significantly between shots anyway, and tweaking by eye is just about as good as any other method anyway. The same is true in other mixed-light situations; a WB reference will get you in the general ballpark, but you're going to have to tweak anyway, based on which parts of the subject are how distant from the various light sources.

Regarding question 2, the answer is no. Since the subject is not the primary light source, changes in subject color do not dramatically change the light color. It has some effect, but not dramatic, unless you change the color of the walls, floor, and ceiling as well. Keep in mind that the diffusion screen/Expodisc is picking up light from a ~180 degree hemisphere, so the subject isn't as significant in that scheme of things as you might think.
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yaya
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« Reply #5 on: December 30, 2006, 01:26:44 AM »
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Sam has pretty much covered it:

If you want accuracy on product, use a Gray card or a macbeth chart

For shooting variable light, like sunrise or sunset, there are a few tricks:

1. use a small flash or a pop-up one if your camera has one, shoot a card and balance it in camera, then let the sun/sky orange/ blue drop in.

2. Use a round "Gray card" - can be a foam core ball or whatever - this way by clicking different points in post, you can find the right balance for the scene.

The diffuser filter supplied with MFDBs is not for WB, it's for correcting colour casts with wide angles and shifts. You also loose about 2 stops with it so you'll have to compensate.

The Expodisc, in my experience, is very inconsistent when used with a digital back, since the backs are more sensitive to slight changes in lighting compared to lower bit depth capture devices.

Yair

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Dustbak
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« Reply #6 on: December 30, 2006, 04:23:28 AM »
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I notice very few people mention color light meters. I use for products a combination of greycard and meter.

Outside I will eye-ball it in post.

Another option for the expodisc would be the lid of a pringles box, at least the thing will not be sticky like the ice cream option  . It is just a tad warmer than the expo disc but comes very close.

Color balancing flash with gel filters is something I will only do when I can control the light completely (studio) otherwise the exercise it kind of futile. Although I have color corrected flash in an operating room once to correct the blue OR light.
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Henry Goh
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« Reply #7 on: December 30, 2006, 06:58:19 AM »
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After spending huge amounts of money on camera systems and MFDB, I would have thought you guys would depend more on a colormeter to get you into that ballpark than expodisc or pringles cap.

Henry
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James Russell
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« Reply #8 on: December 30, 2006, 09:31:23 AM »
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After spending huge amounts of money on camera systems and MFDB, I would have thought you guys would depend more on a colormeter to get you into that ballpark than expodisc or pringles cap.

Henry
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If you mean a color meter on set, I don't know how you translate that to the actual back or capture because the db's are not moveable in kelvin until you get to post.

At that point the input profiles and the just the way the software reads the file makes a difference in how the curves are twisted.

Still, few of us with film balanced to be exact or by the numbers.  We usually shot certain films because they had color responses that we found pleaseing, depending on what we shot.

Now we try to do those looks in photoshop though as the convertors like lightroom wokrking in channels or  C-1 working in channels and the color editor have matured and allow seperate channel correction  so we can build our own film.

I think Leaf has a color editor in LC10 but I believe it's an added cost, though I know little about it.

It's a mindset of how you want to work.  Do you want the convertor to produce a negative that goes into photoshop to make a print or a transparency that is ready for print?

I see the convertors going more to the transparency stage than the negative stage.

I got to 95% of this color in lightroom and then added texture and grain in ps, where previously I would have done 85% of the color in photoshop.



The db's especially the aptus is very sensitive to Kelvin change, which in some instances is excellent because it reads everything and other times is not so excellent, depending on the subject and the desired effect.

Still, rather than shooting just a white disk or card or even trying to click balance on single versions of gray something like this might be more useful.



JR
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bcroslin
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« Reply #9 on: December 30, 2006, 10:01:17 AM »
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I've had good luck using a macbeth color checker. Just using a grey card doesn't cut it because I then have to go searching for a true white and that's not always do-able.

If I have time I use the ACR calibrator script and it nails the color every time IMO:

ACR Calibrator
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Bob Croslin, Photographer
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Craig Murphy
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« Reply #10 on: January 01, 2007, 11:55:06 AM »
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ACR Calibrator doesn't work with my version of ACR.  Looks like they have not kept up with new updates.
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CMurph
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« Reply #11 on: January 02, 2007, 01:36:47 AM »
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More likely you haven't, unless you're running the new CS3 beta. I have the latest version of ACR in PSCS2 and Fors' script works just fine for me...
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Craig Murphy
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« Reply #12 on: January 02, 2007, 09:03:01 AM »
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Something odd has happened since I downloaded the CS3 beta for windows.  ACR in CS2 will no longer just open a file when clicking on 'open'.  I have to go to 'save' in order to get an image to do so.  I am also getting a message telling me that 'this version of acr is beta and has expired on 12-31-06.  I can continue to use it but will get this message once a day.'  Where the hell did that come from?  I just deleted and then redownloaded the ACR update (3.6) but still files will not open and chromoholic is still telling me that my version is not supported.  Chromoholic worked just fine before I downloaded CS3 beta but I'm using CS2.  Just tried to open a raw file in CS3.  No can do.  Only if I 'save'.  Not 'open'.
« Last Edit: January 02, 2007, 09:23:25 AM by Craig Murphy » Logged

CMurph
phildog33
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« Reply #13 on: January 02, 2007, 10:30:02 AM »
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what is the consensus for using the 1Ds and Phase P25/Hassy Combo?

I have experimented with the Expodisc on the Canon and it nice and accurate in the studio, but it makes interior architecture shots Very cold looking if the walls are painted, or etc.

I can adjust the White Balance in RAW anyways, but i thought the Expodisc would save us time by using it.

Any tips from users of both?
-p
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awofinden
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« Reply #14 on: January 02, 2007, 03:53:10 PM »
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Whats the diff between using a grey or white card for white balance? Which is best?
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bjanes
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« Reply #15 on: January 02, 2007, 05:12:43 PM »
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Whats the diff between using a grey or white card for white balance? Which is best?
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Either can be used, and Nikon suggests either a white card or gray card in the D200 manual. However, the white card should not be exposed anywhere near clipping. Adobe Camera Raw will not accept such an exposure for white balance. A  very dark exposure will have excessive noise.

Bill
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awofinden
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« Reply #16 on: January 03, 2007, 06:14:02 AM »
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Either can be used, and Nikon suggests either a white card or gray card in the D200 manual. However, the white card should not be exposed anywhere near clipping. Adobe Camera Raw will not accept such an exposure for white balance. A  very dark exposure will have excessive noise.

Bill
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Do you know if either one is prefferable?
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David WM
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« Reply #17 on: January 03, 2007, 07:30:14 AM »
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Do you know if either one is prefferable?
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I'd suggest if you're shooting a high key subject where colour imbalance is more obvious then the white would be more useful, gray for a low key image. A cast in the shaddows is a lot less obvious so its more important to get the midtones & highlights accurate, but it depends on your priority for the image.
I found my Kodak 14n had a big magenta shift in the shaddows, but the e22 is very consistent.
I am keen to get more automated in my colour management from the capture stage, and I think this is a very useful thread. I found gray cards useful so long as you understand their limitations due to contamination from the subject or varied light sources. I don't think that colour is something that can be completely automated, but automation should be able to save file prep time and still need the photographer's judgement to make the  decisions.
David
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