Could use some white balance advice

[Gavjenks]

Out the window I saw two male cardinals in the euonymus hedge. One was quite a bit oranger than the other. Your database would have to store an average value for male cardinal.

Biologicals aren't very good things to rely on for that reason (products and building materials etc. are better due to manufacturing tolerances that are usually almost as good as the ones for your gray card), so ideally it would use neither.

Conveniently, though, when you're shooting cardinals, they are (hopefully!) outdoors, so the GPS coordinates can simply allow the computer to figure out exactly the real light color that existed at that moment independently of the image (as discussed above, this is already in development), making it a moot point.

The two systems mesh almost perfectly. Indoors = almost always consistently manufactured materials in sight that will be as useful as a card usually. Outdoors = just use GPS and the clock and done.

A little 3MP cell phone-ish sensor in the body would assist either to be even more effective (often will be able to direct measure the light indoors making object recognition unnecessary as well, and can help identify outdoors or indoors if ambiguous).




None of this technology is futuristic. It all exists, but is merely uncommercialized for these purposes.

 

[Ysarex]

"Theory: AWB sets the white balance by analyzing the photo taken. That can't produce an accurate result without a prior measurement of the spectral reflectance properties of the subject. There's no way the camera can know the spectral reflectance properties of the subject. Therefore AWB in theory can't work. In practice we know it certainly doesn't work."

Somebody SERIOUSLY needs to check into the distance-aware, color-aware, reflectance-aware metering and white balance systems Nikon has been using for years now. You seem to be unaware of the newer techynologies involved in "modern" cameras. It is no longer 1969.

The D2 series featured an external white balance sensor, a small, white-colored sensor, located on the front of the pentaprism, which took "external" color temperature readings, and compared those against internal color temperature sensing. As it turned out, Nikon dropped that external sensor in the D3 series.(Because it was not needed!)

Dude...it's pretty damned simple for a modern d-slr to measure color temperature of ambient light. Minolta was doing it way back in the Reagan years, over 30 years ago. Today's modern d-slr cameras have more computing ability than a collection of the crude computers that sent the first Apollo mission ship to the Moon's surface.

And just an added tidbit, related to Gav's comments above: modern d-slrs know the city the camera is in, as well as the time of day, the exact day of the year, and the lat/long coordinates. Along with 100,000+ actual photos, it's pretty easy for a model to be constructed that measures ACTUAL RGB values, and reflectance values, and distances, and it become pretty easy for a camera's computer to measure and analyze scene recognition data (What Nikon calls the scene recognition system, or SRS) and compare the SRS data against actual, measured data, and arrive at a damned close rendering of the white balance.

Let's cut the bullsh!+, okay: If Auto WHite Balance didn't work, then ACTUAL photos made would have WILDLY inaccurate and wildly varying white balance over 100 frames. But that is NOT the case, and AUTO WB is remarkably consistent under almost all natural, outdoor lighting scenarios, and quite good under most indoor lighting scenarios.

And, at least in Nikon's case, there is analysis of 420, to 1005, to literally thousands, of objects and their spectral reflectance, for every single metering and WB assignment the camera does. After 15 years of trying, Canon has finally managed to get around Nikon's intellectual property in this area, and has now come up with its own "four-hue" method of measuring and metering [Canon calls this iFCL metering]. Again; if Auto WB could not work, then there would never be any successes with it, but pretty simply, it works incredibly well, and has incredible consistency and repeatability. So, somehow, somebody didn't get your "memo".

Cutting through all the BS -- we're going to have to disagree. I acknowledged (in this thread) that AWB has improved a lot. Happy to say that again -- it's gotten a lot better. Happy to also acknowledge that Nikon does the best job of the various camera makers. But we must have different standards and expectations. I for example don't like this:



One of my students took that beginning of the semester. That's AWB in a Nikon D5100 crashing and burning. That one's particularly bad, but basically I see Nikon AWB failures all week long in my students' photos.

Agreed: I see a lot of AWB doing a good job as well. Give the camera a nice colorful sunny day scene and AWB will return a good result. Everybody just photograph nice colorful sunny day scenes and we can stop this discussion.

What I have on my side of this discusion is this pesky stuff called evidence. Sure, there's plenty of evidence showing AWB working well. But what the AWB works argument needs is no evidence showing it working poorly, and I've got lots of that. All you have to do is go to DPReview or PixelPeeper and start looking through the sample photos. Are there more AWB successes than failures? Yes. But there are still too many failures.

D7100
3Kings Parade | Flickr - Photo Sharing!

inconsistent AWB with same subject
Luna | Flickr - Photo Sharing!
Here I Come! | Flickr - Photo Sharing!

Our little artist - photographer | Flickr - Photo Sharing!
026 | Flickr - Photo Sharing!
DSC_2830 | Flickr - Photo Sharing!
DSC_1764 | Flickr - Photo Sharing!

same cat same place different AWB
Untitled | Flickr - Photo Sharing!
Untitled | Flickr - Photo Sharing!

A pair of Giraffe siblings. | Flickr - Photo Sharing!
_DSC3654 | Flickr - Photo Sharing!
_DSC3585 | Flickr - Photo Sharing!
Pat's Hill Cork | Flickr - Photo Sharing!
Ryder | Flickr - Photo Sharing!
Rusty | Flickr - Photo Sharing!

D5200
DSC_1311 | Flickr - Photo Sharing!
DSC_00461 | Flickr - Photo Sharing!
20131119Lime Bay Park032.jpg | Flickr - Photo Sharing!

D800
The River Runs | Flickr - Photo Sharing!

inconsistent birds
_DSC5185 | Flickr - Photo Sharing!
_DSC5206 | Flickr - Photo Sharing!

D8X_4918 | Flickr - Photo Sharing!
Splash | Flickr - Photo Sharing!
D8C_6839 | Flickr - Photo Sharing!
CWD_6079 | Flickr - Photo Sharing!
CWD_6119 | Flickr - Photo Sharing!
CWD_6140 | Flickr - Photo Sharing!
Famille & Surveillance | Flickr - Photo Sharing!
Erlebniszoo Hannover | Flickr - Photo Sharing!

Could do that all day and list pages of bad Nikon AWB.

So I'm just too fussy and it doesn't matter if pretty models have blue hair. Obviously to a lot of people it doesn't matter or they just can't see it.

Trifles make perfection, and perfection is no trifle.
-- Michelangelo

Joe

 

[Ysarex]

Out the window I saw two male cardinals in the euonymus hedge. One was quite a bit oranger than the other. Your database would have to store an average value for male cardinal.

Biologicals aren't very good things to rely on for that reason (products and building materials etc. are better due to manufacturing tolerances that are usually almost as good as the ones for your gray card), so ideally it would use neither.

Conveniently, though, when you're shooting cardinals, they are (hopefully!) outdoors, so the GPS coordinates can simply allow the computer to figure out exactly the real light color that existed at that moment independently of the image (as discussed above, this is already in development), making it a moot point.

The two systems mesh almost perfectly. Indoors = almost always consistently manufactured materials in sight that will be as useful as a card usually. Outdoors = just use GPS and the clock and done.

A little 3MP cell phone-ish sensor in the body would assist either to be even more effective (often will be able to direct measure the light indoors making object recognition unnecessary as well, and can help identify outdoors or indoors if ambiguous).




None of this technology is futuristic. It all exists, but is merely uncommercialized for these purposes.

And some of what you're describing like a 3MP sensor is no longer AWB -- that would be taking an actual measurement! A GPS database is also not AWB -- that's analogous to using a camera WB preset.

Joe

 

[Gavjenks]

Automatic - Definition and More from the Free Merriam-Webster Dictionary

of a machine or device : having controls that allow something to work or happen without being directly controlled by a person

Understanding White Balance

White balance (WB) is the process of removing unrealistic color casts, so that objects which appear white in person are rendered white in your photo.

Both top-of-body sensor and GPS weather data are means of removing unrealistic color casts without being directly controlled by a person. Hence, They are "automatic white balance."




If you want to arbitrarily define AWB as some special meta-term that means "only stuff that doesn't work," rather than what the actual words mean, well then yes, I agree that your special Ysarex defined meaning of "AWB" is "impossible" to make work, tautologically. :roll:

 

[Ysarex]

Automatic - Definition and More from the Free Merriam-Webster Dictionary

of a machine or device : having controls that allow something to work or happen without being directly controlled by a person

Understanding White Balance

White balance (WB) is the process of removing unrealistic color casts, so that objects which appear white in person are rendered white in your photo.

Both top-of-body sensor and GPS weather data are means of removing unrealistic color casts without being directly controlled by a person. Hence, They are "automatic white balance."




If you want to arbitrarily define AWB as some special meta-term that means "only stuff that doesn't work," rather than what the actual words mean, well then yes, I agree that your special Ysarex defined meaning of "AWB" is "impossible" to make work, tautologically. :roll:

No you don't get away with that -- AWB is a well understood methodology: You take the photo without a direct measurement of the light source and without a known spectral reflectance target in the photo. You then determine WB by analysis of the recorded data. My comment referred to AWB, not AWB plus K degree presets and a sensor on the camera. A camera body sensor is a direct measurement of the light source -- it's one of the things I've said all along that does work. I'll accept your database of averages as a way to improve AWB; you don't get to expand the definition of AWB to include the very things that I say work. The theory behind auto white balance is that you can determine WB by analyzing the data recorded without a direct measurement of the light source. :roll::roll:

Joe

 

[Gavjenks]

You take the photo without a direct measurement of the light source

[citation needed]

I've never heard that extra stipulation before ever. And basic common sense as well points to the default understanding of a straightforward term like "auto white balance" being defined quite simply as "white balance that is set automatically." A body sensor is automatic. And it sets white balance. So it's automatic white balance... there are no other words there unaccounted for...

By all means though, share some links from photography encyclopedias or authorities like cambridgeincolor that specify otherwise. I'm happy to learn more about experts' word on a term if in fact I've been misusing it.

 

[Ysarex]

You take the photo without a direct measurement of the light source

[citation needed]

I've never heard that extra stipulation before ever. And basic common sense as well points to the default understanding of a straightforward term like "auto white balance" being defined quite simply as "white balance that is set automatically." A body sensor is automatic. And it sets white balance. So it's automatic white balance... there are no other words there unaccounted for...

By all means though, share some links from photography encyclopedias or authorities like cambridgeincolor that specify otherwise. I'm happy to learn more about experts' word on a term if in fact I've been misusing it.

Sorry for the delay -- had to go help out in the garden.

http://www.stanford.edu/~sujason/Co...gorithm using Gray Color Points in Images.pdf

Try and weasel all you want AWB is a well understood function in a modern camera. It is clearly differentiated by the other WB functions of a modern camera which include 1. Taking a measurement and 2. Using a preset value. AWB is neither of those and does neither of those things. If if did then why are those separate features there? :roll::roll::roll:

Joe

http://www.google.com/url?sa=t&rct=...sg=AFQjCNEYXtPY0kZYvAePOaPaYjcLeBjYrA&cad=rja

This one's from Nikon -- I love this one: "A popular technique of color-balancing, which should generally be avoided in critical applications, is commonly referred to in consumer cameras as automatic white balance adjustment. This method is intended to be applied to the image field as the image is acquired and functions by evaluating the overall field of view, averaging the light values present with respect to hue, and attempting to average, or zero-out, any overall color bias. The shortcoming of automatic balancing techniques is that the color values present in any viewfield represent an "average" distribution of hue, which are combined to produce a neutral gray or white. In effect, if the summed pixel response is not similar to the programmed (expected) overall average, the white balance adjustment made by the camera will not produce accurate color rendition." Here's the website: Nikon MicroscopyU | Color Balance in Digital Imaging

You gotta love that last one -- Nikon says it doesn't work!

 

[480sparky]

You two go ahead and keep arguing. I'm gonna go shoot something.

 

[midomidi2013]

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better results. Auto is not a light source. It's just the camera's way of guessing, and not only is it unnecessary most of the time but it's usually several hundred degrees Kelvin off. Even if there's white in the scene, it usually contains some color cast, from the sky if nothing else, and therefore is unreliable as a WB target in auto or post. I can't advise auto as a solution when you know the light source. If the barn is lit by the sun, set the WB to sun. If it's lit by a tungsten light bulb, set it to light bulb. If you want to be more accurate, place a white card in the same light as the barn. Then you can use it for a custom WB or simply select it in post for accurate WB (which works better in RAW). However, note that if you're shooting sunrise or sunset, you don't want to do custom WB because that will neutralize the golden hue of the light. You want to leave WB at daylight during those hours to preserve the natural colors.

Guessing actually adds difficulty in processing. Yes, if you shoot RAW you can select any WB in post, but that's just guessing. Without a known color-neutral target in the frame, you'll struggle with sliders and trying to remember what the scene looked like, which is even worse if your monitor isn't calibrated. With custom, you know it's correct without guessing. When using a white card, it should be something like the ColorChecker from X-Rite. Some exposure gray cards actually have a color cast that won't help with WB.

Auto WB is neither exact, consistent, organized nor repeatable. Even under the same light, auto can change depending on where you point the camera, and so you could have 100 images under the same light each with a slightly different WB, making it even harder to figure out which is correct in post. Auto can be a handy tool, as sometimes there's no other way to estimate the light temperature. That still means more work in post. However, if you compare a series of different scenes shot in auto to the same scenes shot in custom or preset, the custom or preset will look better to most people. Auto appears to be OK in the viewfinder and when not compared to anything else, but when you put it against custom or preset, it's rarely as accurate. If you have the time, try to match the WB exactly to the source.

I am disillusioned enough to know that no man's opinion is worth a damn unless backed up with enough genuine information to make him really know what he's talking about. ~ H.P. Lovecraft

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