OM-D white balance "area" test

Klorenzo

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Hi, I found a little strange that the manual says to fill the whole display for custom white balance. It's quite hard to do it with a small gray card without dropping shadows over it.

So I did a couple of test shots to see if I could use a smaller area as it happens with other cameras. And yes, it looks like only the central area of a 3x3 grid is used (approximately).

I do not know if/how much this is well known.
 

Klorenzo

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Use a large sheet of 'white' paper, as recommended on the camera info.
Can you elaborate a little? For me is not practical to bring around a large neutral (white/gray) sheet of paper, even an A5 format.

So, with artificial light, I placed the WB white card over a yellow background and measured three different custom WB. One filling the frame, one leaving a small yellow border and one with a large yellow border. The camera refused to read the WB from the yellow background only.

Then I took three picture of a multi coloured subject with the different settings and I could not found (visually) any difference. I didn't shot raw so I can not check the exact temperature value.

It's not a very extensive test, but results were good and it also matched my experience with panasonic and canon cameras.
 

owczi

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I always carry a coffee filter under the insert of my bag. Just put the filter over the lens and measure WB of that. Alternatively you can use a plastic coffee cup cover. Well, or just shoot RAW and do what you want with the WB later.

But as to the original post - yes, whenever I needed custom WB I would usually pick the thing nearest to white I could find and it worked fine, it didn't have to be big at all. Doesn't have to be big, I think possibly the software picks the dominating shade as reference, or indeed uses part of the frame only.
 

Joon525

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But as to the original post - yes, whenever I needed custom WB I would usually pick the thing nearest to white I could find and it worked fine, it didn't have to be big at all.
That is what I do.

I also have an app that has a WB card feature BUT i just then thought to myself....use your smartphone to take a picture of a white sheet of paper and then use the picture on the phone as a white card without having to download any app?
You could even take multiple pictures of varying shades and use any of them when appropriate.
 

Klorenzo

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I also have an app that has a WB card feature BUT i just then thought to myself....use your smartphone to take a picture of a white sheet of paper and then use the picture on the phone as a white card without having to download any app?
Ehm...I think that you should take a picture of a perfectly neutral white card WITH the white balance already set correctly on the phone...it looks circular to me. And I wouldn't trust the display calibration too much.

Anyway use what works best for you, I use (rarely) a 7x10cm "gray 18"/white thick card cut out of a bigger sheet. I am happy to discover that I can avoid acrobatics and use the central area only.
 

Matero

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That is what I do.

I also have an app that has a WB card feature BUT i just then thought to myself....use your smartphone to take a picture of a white sheet of paper and then use the picture on the phone as a white card without having to download any app?
You could even take multiple pictures of varying shades and use any of them when appropriate.
Wait a minute, I think here is little bit confusion between emitted light and reflected. Display of phone emits light, white or what so ever. And WB correction is needed when light source emitting light with different wave lengths reflects differently from objects making white looking not-so-white. Emitting phone display does not reflect surrounding light.
 

Joon525

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Emitting phone display does not reflect surrounding light.
Oh yeah I agree 100%. Let me put it this way....it helps but isn't perfect. I try to reach "perfection" in Lightroom. The previous message is definitely not the definitive and final answer/solution.
 

Klorenzo

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Oh yeah I agree 100%. Let me put it this way....it helps but isn't perfect. I try to reach "perfection" in Lightroom. The previous message is definitely not the definitive and final answer/solution.
I think Matero warning is correct: in this way you are reading both the LCD emitted light AND the ambient light bouncing on the glass and on the LCD. If the ambient light is very strong maybe it will be overtake the emitted light and, again maybe, it could work. But otherwise you are reading a light completely different from the one in the scene.

If instead it works reliably it would be interesting to understand the reason, I could learn something from it.
 

Matero

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Oh yeah I agree 100%. Let me put it this way....it helps but isn't perfect. I try to reach "perfection" in Lightroom. The previous message is definitely not the definitive and final answer/solution.
Yes, of course you do what you like and how you get best results for yourself. And I don't want to start any argument over this, but I have to say I know something about light and colors. I've done numerous labs of optics, color, digital signal processing, system calibrations etc and have a degree in graphic arts technology. And I strongly believe I know it is wrong way to correct WB using smartphone display and picture of white paper.

But as said in the beginning, if you feel that it gives you better results, then go ahead. World is amazing, and I've been out of technology part for a long time. Maybe it's changed, I'm happy to learn new things.
 
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