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Old Oct 24, 2011, 12:10 PM   #1
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Default Color Temp variations in iAuto mode

My wife was shooting with the E-PL1 while I was out for my annual trot in the Niagara Falls Marathon (my wife allows me to only do the half). Looking at the results I was rather intrigued how the white balance varied between shots.

Below are two that really show the difference. The first shows the following settings in the exif data:
White Balance: 5300K
Picture Mode: i-Enhance:Standard
Light Source: Fine Weather
White Balance: Manual white balance

The second shot shows the exif data as:
White Balance: Auto
Picture Mode: i-Enhance:Standard
Light Source: unknown
White Balance: Auto white balance

Yes, the framing is changed between shots, maybe enough to throw off the colour temp. But as I go through more shots, the amount of sky to ground does not seem to appear to have a direct correlation to recorded colour temperature.

Looking at this from the point of view of a p 'n' s graduate, it would be rather disappointing to move up to this series of cameras and have such a wandering white balance. Going from an Ektachrome to a Kodachrome between two shots is a bit jarring. Not that I don't like the K'chrome look -- it brings out the warmth of the fall day.

But now it has me wondering about looking at all my shots with an eye to my use (and trust) of Auto White Balance. Curious if others are seeing this...
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Old Oct 24, 2011, 1:29 PM   #2
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Looking at the EXIF data you included, the white balance setting was changed. The first data set shows a manually set white balance of Daylight, while the second set shows white balance set to auto. That's the difference. Could have been accidently changed....there's no telling why or how it happened, but it appears it did.

If you shoot JPEG and you want a consistent white balance applied across a large set of images shot under similar lighting conditions like the two posted above, the best setting for white balance is to not use auto white balance, but manually dial in one setting that is consistently applied across all images.

If you have shot film before, normal slide and color print film is all balanced for daylight shooting, which would be similar to just setting white balance to the sun icon in the super control panel(daylight). If you prefer a warmer setting you can change the white balance to shade or even cloudy, but the daylight setting will give a more consistent result for all outdoor shooting under sunlight.
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Old Oct 24, 2011, 4:12 PM   #3
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I see that the colour temperature has changed, but between two shots taken less than 20 seconds apart, I would not expect the camera's white balance to be this random. I know leaving it on Auto is leaving things up to chance a bit. I would have thought that on iAuto the sensitivity might be "dumbed down a bit" to record more consistent results.
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Old Oct 24, 2011, 4:47 PM   #4
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Auto white balance is very neutral, to cool, from what I have seen across several Olympus bodies, both DSLR's and Pens. I'm not suprised at all in this color difference. You could probably stand outside right now (assuming it's daylight) and shoot two images 5-10 seconds apart using auto WB once and then daylight WB settings and see the same difference. If the white balance had been left to auto in both shots I do not doubt the colors would have been close to, if not perfectly identical.

Any more I just leave white balance set to daylight even though I shoot RAW 99% of the time as it is always a good choice either outdoors or indoors shooting with flash. Once you get indoors with no flash, the funky color given by a daylight setting under artifical lighting in the finder view makes it obvious it's necessary to make a white balance change. If I think to I change it. If not, I'll make the white balance setting change in the raw converter.

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Old Oct 24, 2011, 9:07 PM   #5
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Quote:
Originally Posted by Greg Chappell View Post
...If the white balance had been left to auto in both shots I do not doubt the colors would have been close to, if not perfectly identical....
That's the thing that gets me here in this instance -- my wife was shooting in iAuto, and not changing the white balance settings. And looking through the shots from that day, you can see the results flipping back and forth from Light Source "Fine Weather" to "Unknown"
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Old Oct 24, 2011, 9:18 PM   #6
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And here are two more flipping from white balance Auto to white balance 5300K. And again set to iAuto, auto white balance. There should not be such a difference between these two shots...
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Old Oct 25, 2011, 9:03 AM   #7
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My guess is that the camera is choosing a warmer WB in auto mode because the weather although sunny, is also very overcast by the looks of it. So, the camera is compensating for that (the kevin value used for shade/cloudy conditions is much higher...around 6600K-7500K). I hardly use "fine weather" WB setting because generally cameras do a pretty good job under sunny conditions. I'd be curious as to how much difference you'd see under blue skies.
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Old Oct 25, 2011, 8:04 PM   #8
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Originally Posted by Tullio View Post
I'd be curious as to how much difference you'd see under blue skies.
About the same.

This evening I shot the two images below from my window at the office shortly before leaving with the E-P3 and Panny 20mm f1.7. 8 seconds between each image, which I used to change the white balance setting from auto to sunny. These were shot in the regular program mode. The only difference between the two, other than my bad leveling in one, was the white balance setting.




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Old Oct 25, 2011, 9:49 PM   #9
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No need to say...w/o looking at the EXIF data, my guess is that the first shot is with WB set to "fine weather" and the second with auto WB. The thing is, although the sky is mostly clear, you are shooting in the shade and again the camera will compensate for that. Next time, try to take both shots under the sun.
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Old Oct 26, 2011, 9:11 AM   #10
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My point when I got going on this, was the randomness of colour temperature that the camera applied to multiple shots in/under similar light conditions, when using the consumer friendly iAuto setting. My wife had not handled this camera before so I set it to the iAuto thinking it would give her good consistent results. She is happy with her captures -- hated the focus control. But the cool to warm variations bug me.
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