Custom White Balance compared to AWB

The myth of automatic white balance still alive and kicking?
(Hint; there isn't any automatic white balance.)

The camera has one entrance for light, the lens. It is usually directed at the scene. The white balance shall mostly be set for the light source, which in most cases is not present within the optical system of the camera. Any reading taken from the scene will be off. By design.

Then of course there are other caveats, but RAW shooting will help you take care of those problems. A white balance reading from a neutral card will render a neutral white balance in the shot, while you might prefer some other white balance to set the mood of the event you shoot. This is the remaining one percent for the photographer that says the card reading is accurate for 99 % of the shots. The reading off the card is correct whenever you wish a neutral colour balance, but when you would like a warmer or cooler rendition, you must tweak it. However, the white balance card reading is a good starting point.

I won't go into the subtler issues of colour rendition or "colour temperature".

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Originally Posted by Inkanyezi

The myth of automatic white balance still alive and kicking?
(Hint; there isn't any automatic white balance.)

The camera has one entrance for light, the lens. It is usually directed at the scene. The white balance shall mostly be set for the light source, which in most cases is not present within the optical system of the camera. Any reading taken from the scene will be off. By design.

Then of course there are other caveats, but RAW shooting will help you take care of those problems. A white balance reading from a neutral card will render a neutral white balance in the shot, while you might prefer some other white balance to set the mood of the event you shoot. This is the remaining one percent for the photographer that says the card reading is accurate for 99 % of the shots. The reading off the card is correct whenever you wish a neutral colour balance, but when you would like a warmer or cooler rendition, you must tweak it. However, the white balance card reading is a good starting point.

I won't go into the subtler issues of colour rendition or "colour temperature".

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Urban I am firmly in your camp but I am even more extreme. Exact WB can seldom be achieved and when it is nearly achieved all you have managed to do is to shift the WB that existed when you took the photograph to something that is closer to viewing the scene in the middle of the day - it certainly does not make it right. For me what is right is how my mind interpreted the WB at the time of exposure. My perception will in fact have performed colour adjustments to the scene based on expectation of the colour of familiar items in the scene. For most photography the WB we seek is related to our perception not the middle of the day.

A white fence in a photograph at sunset would look unnatural if "correct" WB was applied. A candle-lit scene is totally wrong and is devoid of the warm ambience with "correct" WB so too is scene taken under moonlight. These examples may seem a bit extreme but they are easy to visualise. However for a photographer the correct WB for any scene is based on the WB that portrays the scene as the photographer wants it to be portrayed.

Note: The above does not apply for reproduction, technical and photography used for reference purposes but these photographs will if at all possible be taken under very controlled and known lighting conditions.

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Originally Posted by AB26

I took a shot of a Clivia in my garden, this morning early. Shot in Jpg WB was preset, unfortunately I had to push ISO to 800 to get a decent shutter speed for a handheld shot. Compare your RAW image to this Jpg image and you will notice a vast difference in colour rendition.

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Of course the leaves on your photo are different to the leaves of the plant on my photo.

It is a different plant.
In a different location.
Under different light.
Shot at a different time.

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Originally Posted by AB26

The leaves of a Clivia is a deep dark green.

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No.

The leaves of YOUR plant might be a deep dark green.
BUT, typically the leaves of MY plant are NOT a deep dark green:
http://backup.cambridgeincolour.com/...7522294-md.jpg

That, as I understand, was one of the points of the Opening Post - to make an image (of a flower) close to how it actually appeared, in situ and not necessarily what “looks best”:

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” Where I find a particular potential problem is with flower photography where I need a reasonably accurate reference. Otherwise, once I try to edit the images a couple of days later I am wondering if a flower was really that colour. And if not what should I do to get a natural result.”

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Originally Posted by AB26

. . . I did not use any fancy gray card to do the preset WB, I did it on a white reflector made from painters canvas. (Steve Sint recons you can do it on a bride’s dress.)

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If you manually set your WB on a Painter’s White Canvas – AND – that canvas was in the same lighting conditions as the Plant – AND - the canvas was indeed “white” then you would have attained a very accurate colour rendition of the leaves of YOUR plant in that PARTICULAR lighting condition.

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Apropos Wedding Photography – making a preset WB from the Bride’s Gown is an approach. It can be accurate. It also can be inaccurate. Many Wedding Photographers (including me) employ this approach. As with any approach or technique knowing the limits of the technique is essential and it would be foolish to apply any technique without understanding those limits, or to suggest that a one size fits all.

That said – and specifically because making a Preset WB from ANY “white” material has limitations – it is safe to advise that using a Photographic Grey Card is more suitable and also more reliable. If one want to mention brand names – the ‘WhiBal’ Card seen right of frame in the above is excellent.

Most Camera Manufacturer’s Technical Notes will make it obvious that, if using a Static Source for WB Set, the use of a Photographic Grey Card is a better source to use 'any white surface’.

All that stated – and especially concerning Wedding Photography especially at the higher end market: more important than attaining close to how the colours were actually rendered in different lighting scenarios is the importance to keep Colour Continuity throughout the Album of the Bridal Gown (if not white) and of the Bridesmaid’s Gowns. This can be very difficult if the Gowns have hues of Purple or Green - AND – accordingly the White Balance of the final will often be subtly changed, to suit the rendition of the gowns such that they are the same throughout. The Photographer may take a sample of the dress material to achieve this goal.

WW

Bill you need to add fertiliser to your Clivia and may be give it a touch of magnesium sulphate or dolomite. Yes it's leaf colour has little to do with WB:p

haha!

Yes.

I am now feeling a tad ashamed that I practice Darwinian Theory in my front garden.
The lawn appears a tad under-nourished and also a little 'draught-affected' - too.

I shall endeavour to be more considerate of my Plant Community.
Perhaps it is time for the liquid fish poo . . .
Thanks for the tip about MgSO4 - I use that for my sore back (in the bathtub) . . .

I am not to familiar with CaMg(CO3)2 - I had to look that fellow up, but I believe I now understand why you suggested it.

I think that the liquid fish poo "solution" has all of that stuff in it as the "added extras" to the "solution". And it really annoys the neighbours, because it sticks - so I might and buy some and use it this next weekend.

Thanks for the horticultural diagnosis, very helpful: do you do house calls?

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Originally Posted by William W

Thanks for the horticultural diagnosis, very helpful: do you do house calls?

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Just provide the the transport and you can have a free consultation.

Unfortunately due to prior fiscal commitments your transport request is unlikely to be fulfilled.

However, negotiation on this matter is possible: if you are in the neighbourhood "refreshments" would be available.

Please note that an extended stay will possibly be required, if we move on from the gardening lesson and we get to "discussing", Sport.

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Originally Posted by William W

Unfortunately due to prior fiscal commitments your transport request is unlikely to be fulfilled.

However, negotiation on this matter is possible: if you are in the neighbourhood "refreshments" would be available.

Please note that an extended stay will possibly be required, if we move on from the gardening lesson and we get to "discussing", Sport.

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Thanks I will keep it in mind provided no labour is involved but I am bitterly disappointed at the current fiscal constraints on both parties.

At the risk of labouring a point here it's interesting to see how a camera actually sets it's colour balance. I've had a look around and it seems that it uses any combination of gray, such as white, shadows or faces in the image. Some or all of you may already know this anyway hence my opening sentance.

So, when I use AWB generally, as long as the image satisfies the above auto WB will work relatively sucessfully. What it won't cope with is if the above is missing entirely. Now a lot of you like your flowers and macro and stuff and I can see you would have considerable difficuly at times meeting enough of the above parameters to get the white point 'just right'.

This then is where us jpeg shooters have the edge. Our cameras being allowed to calculate from multiple sample points probably have a better chance of getting white balance right than we would in a raw convertor as do raw convertors have multiple white point sampling? Canon DPP doesn't. Being 'right' of course is different to 'desirable'.

This last saturday I had a Mayoral Visit to cover for the dance school I shoot for on a regular basis. Now I've had some issues there in the past and set custom white balance which wasn't that sucessful because of flouros and I'm sure some of you can remember my posts a while back. I shot them raw earlier in the year with custom WB and struggled in post to get them anywhere good enough for me.

So, Mayor arrives, shoot the lot in jpeg, auto WB, aperture priority at 800ISO and blow me the damn things have come out exactly spot on whereas earlier in the year they looked a tad muddy from the raw converter. I opened everyone of them in DPP and Explorer and none needed a touch up.

Considering the camera does all this in a split second and pops out a jpeg which needs no more work I think it's a marvellous thing (this auto WB) and I think all you raw shooters should be consigned to the loony bin/asylum for good measure ... :D

Just thought I'd share this revelation :)

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Originally Posted by SteveF

do raw convertors have multiple white point sampling? Canon DPP doesn't.

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Nikon's Capture NX and NX2 are the only raw converters I have ever used and they allow multiple-point sampling.

I'd like to make a comment on nomenclature here:
White point has nothing to do with white balance, the white point in an image is chosen for exposure, the point where all three channels will saturate. In PP, the right handle of "levels" or the upper right anchor in "curves" is the white point.

White balance can be taken from any neutral field in the image, and it is possible to use multiple points to integrate for white balance. The brighter the white reference point is, and the more pixels that are included, the higher the precision when white balance is set. Hint: don't try setting white balance from a dark grey field, use one that is as bright as possible, but not near clipping in any of the colour channels. That is why the WhiBal card is way brighter than a grey card, and manufacturers recommend a white reference for setting the custom balance. My preferred reference is a piece of plastic cut from a milk container, which is not completely neutral, but spectrally congruent. It does not change appearance under different lighting, but is always near white. The WhiBal is slightly "warmer" in tone and delivers a cooler white balance. But the homemade one works equally well for all light sources I have tested, so I stick with it, as I prefer the slightly warmer balance it provides.

So even though the WhiBal is an extremely good reference, one might prefer one that actually is a bit off, for personal reasons. It is however important that results should be consistent. My milk container fragment is akin to using the WhiBal but increasing colour temperature of the light source in the converter.

I'm not quite sure why I said white 'point' when I clearly mean 'balance'.

I'm losing it obviously .. :rolleyes:

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Originally Posted by William W

haha!

I think that the liquid fish poo "solution" has all of that stuff in it as the "added extras" to the "solution". And it really annoys the neighbours, because it sticks - so I might and buy some and use it this next weekend.

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When thrown, Bill? A Freudian slip, perhaps? ;)

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Originally Posted by SteveF

So, Mayor arrives, shoot the lot in jpeg, auto WB, aperture priority at 800ISO and blow me the damn things have come out exactly spot on

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Steve I did a wedding on Saturday (07 Sept) all done with one lens - 35mm F1.8 and shot in Jpg. WB I twiddled with between Kelvin and that little flash sign. Got the warmth and atmosphere I was looking to get in the shots. Will post some in another thread.
Crazy shooting Jpg only! :D

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Originally Posted by Inkanyezi

My preferred reference is a piece of plastic cut from a milk container, which is not completely neutral, but spectrally congruent.

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Glad to see I am not the only "crazy" guy around here. Sometimes I use a white plastic shopping bag to do Pre-set WB. :D Must say it does a pretty good job. You can actually turn the lens into the light source doing Pre-set WB with a shopping bag. Do other countries still use plastic shopping bags??

That poo solution seems a bit fishy...

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Originally Posted by AB26

Glad to see I am not the only "crazy" guy around here. Sometimes I use a white plastic shopping bag to do Pre-set WB. :D Must say it does a pretty good job. You can actually turn the lens into the light source doing Pre-set WB with a shopping bag. Do other countries still use plastic shopping bags??

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We do Andre but, they're a bit low on the polictically correct scale at the moment due to the amount now being found in wildlife stomachs. Particulary seabirds.

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Originally Posted by AB26

Steve I did a wedding on Saturday (07 Sept) all done with one lens - 35mm F1.8 and shot in Jpg. WB I twiddled with between Kelvin and that little flash sign. Got the warmth and atmosphere I was looking to get in the shots. Will post some in another thread.
Crazy shooting Jpg only! :D

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You do realise we'll soon be on the 'hit-list' for disclosing this info :cool:

:)

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Originally Posted by William W

Darwinian Theory being practiced: no political correctness and no second chances.

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Australia 12 - South Africa 38. Darwinian Theory being practised??????????? :D

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Originally Posted by AB26

Glad to see I am not the only "crazy" guy around here. Sometimes I use a white plastic shopping bag to do Pre-set WB. :D Must say it does a pretty good job. You can actually turn the lens into the light source doing Pre-set WB with a shopping bag. Do other countries still use plastic shopping bags??

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Andre - I wouldn't suggest you are crazy or alone in this respect; the professional (and semi-professional) photographers that I know that shoot mainly or exclusively shoot jpegs tend to be wedding photographers (who do this because of the very tight timelines they are working under; with a SOOC product delivered for the bulk of the images) and sports photographers (who are limited by capacity of their camera buffers).