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planedriver · 12-19-2009, 03:45 AM

Hello everyone! I have a question regarding the AWB performance of the K-x. I took these two pictures within two seconds however one looks noticably colder than the other.

Both taken with the FA50 f2.5 1/60 iso1600 within a second or two. Natural lighting coming from the terrace door. WB set to auto.

Any ideas what caused the difference?

Thanks Andras

DonP · 12-19-2009, 07:10 AM

Any chance you can supply the exif data for each of the photos? Is it possible that while you had exposure and focus locked a cloud came between the sun and your window (or was there and left)?

planedriver · 12-19-2009, 07:21 AM

Originally posted by DonP

Any chance you can supply the exif data for each of the photos? Is it possible that while you had exposure and focus locked a cloud came between the sun and your window (or was there and left)?

No today it's total grey overcast. And snow. BTW here is the link to the flickr page. There is no other picture there apart from these two.

Flickr: andras1977's Photostream

Thanks Andras

DonP · 12-19-2009, 11:33 AM

The exif doesn't show from the photos using the link. Are these crops from a larger image? It's hard to tell why the WB would be different between two shots taken seconds apart.

planedriver · 12-19-2009, 11:58 AM

Originally posted by DonP

The exif doesn't show from the photos using the link. Are these crops from a larger image? It's hard to tell why the WB would be different between two shots taken seconds apart.

No crops. If you open the picture in the flickr and go to the "more properties" you get to the exif data I guess. I'm not sure

Andras

SteveB · 12-19-2009, 12:25 PM

Everything that matters in the EXIFs are the same. Mystery. I guess the AWB made a different guess on each shot.

Jaleel · 12-19-2009, 12:28 PM

Look at the "autocorrection of white balance" in menu.
Something like this. I read a thread in russian forum about the same problem in K-7.

melander · 12-19-2009, 12:31 PM

I have had that happen to me indoors 3000k, when doing a 4fps run it could be spot on 3 pictures and beeing set to 5000k for one. I shoot in raw, so I havent bothered with it.

Marc Sabatella · 12-19-2009, 02:29 PM

AWB is always just a guess based on the colors the cameras sees. If nything at all changes about the scene - even the slightest thing it could affect the results. Here, the framing and or hands moved so that the ratio of skin to plate changed; I'm guessing that's what did it - although I'm surprised it made *as much* difference as it did.

Basically, if you care about WB, you don't let the camera choose it for you. AWB is fine if you shoot RAW and can correct it later, but if you shoot JPEG and differences like this matter, then you need to set it yourself, because AWB is really just a guessing game.

planedriver · 12-20-2009, 08:59 AM

Thanks for the feedback!

Andras

Eruditass · 12-20-2009, 09:13 AM

I've also had this problem, like it was jumping between strong and weak tungsten (or something else) where the source of lighting was only tungsten and did not change. Didn't notice it with a K2000 or K10D, I'd be interested to see if most K-x users experience this or if K-7 users do to.

Mildly annoying, but I shoot in RAW.

planedriver · 12-20-2009, 09:28 AM

Originally posted by Eruditass

Mildly annoying, but I shoot in RAW.

I shoot RAW too-yes it's mildly annoying. I'm just rather curious. It's good to know what's going on in your camera. Also noticed that shooting in the house under natural lighting conditions (so the windows are the light sources)some areas where the light is reflected ( for example floor) can look very cold (blue) on the picture.

Andras

Optical Illusion · 01-01-2010, 08:39 PM

I was outside under a cloudy sky today practicing with the K-x and an M50 1.7 lens. I was taking shots of some green painted wood and was not looking at each shot. Then I noticed one where the green looked almost brown! What? I thought the LCD colors were off or something - I switched from AWB to 'sunlight' and the color looked correct. Still I was surprised and dissappointed at how far off Auto was...outside! Does that mean I really can't trust it? I have never really worried about it on P&S camras. Should I carry around a piece of white copy paper with me? I thought this tended to be more of an issue inside under artificial light.

Marc Sabatella · 01-02-2010, 10:38 AM

It's an issue with an camera any time a scene is dominated by one color. The camera sees that color and has absolutely no wy of determining if the objects in the scene really are that color or if it just looks that way because the *light* is that color. No matter which way it guesses, it is going to be right sometimes and wrong sometimes.

12-19-2009, 03:45 AM	#1
planedriver Inactive Account Join Date: Feb 2009 Location: Velence, Hungary Posts: 664	K-x White-balance question Hello everyone! I have a question regarding the AWB performance of the K-x. I took these two pictures within two seconds however one looks noticably colder than the other. Both taken with the FA50 f2.5 1/60 iso1600 within a second or two. Natural lighting coming from the terrace door. WB set to auto. Any ideas what caused the difference? Thanks Andras

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12-19-2009, 07:10 AM	#2
DonP Inactive Account Join Date: Nov 2009 Location: Indiana Posts: 101	Any chance you can supply the exif data for each of the photos? Is it possible that while you had exposure and focus locked a cloud came between the sun and your window (or was there and left)?

12-19-2009, 07:21 AM	#3
planedriver Inactive Account Join Date: Feb 2009 Location: Velence, Hungary Posts: 664 Original Poster	Originally posted by DonP Any chance you can supply the exif data for each of the photos? Is it possible that while you had exposure and focus locked a cloud came between the sun and your window (or was there and left)? No today it's total grey overcast. And snow. BTW here is the link to the flickr page. There is no other picture there apart from these two. Flickr: andras1977's Photostream Thanks Andras

12-19-2009, 11:33 AM	#4
DonP Inactive Account Join Date: Nov 2009 Location: Indiana Posts: 101	The exif doesn't show from the photos using the link. Are these crops from a larger image? It's hard to tell why the WB would be different between two shots taken seconds apart.

12-19-2009, 11:58 AM	#5
planedriver Inactive Account Join Date: Feb 2009 Location: Velence, Hungary Posts: 664 Original Poster	Originally posted by DonP The exif doesn't show from the photos using the link. Are these crops from a larger image? It's hard to tell why the WB would be different between two shots taken seconds apart. No crops. If you open the picture in the flickr and go to the "more properties" you get to the exif data I guess. I'm not sure Andras

12-19-2009, 12:25 PM	#6
SteveB Veteran Member Join Date: Mar 2007 Location: U.K. Posts: 685	Everything that matters in the EXIFs are the same. Mystery. I guess the AWB made a different guess on each shot.

12-19-2009, 12:28 PM	#7
Jaleel Forum Member Join Date: May 2008 Location: Moscow, Russia Photos: Gallery Posts: 73	Look at the "autocorrection of white balance" in menu. Something like this. I read a thread in russian forum about the same problem in K-7.

12-19-2009, 12:31 PM	#8
melander Veteran Member Join Date: Jul 2008 Location: Sweden, Umea Posts: 876	I have had that happen to me indoors 3000k, when doing a 4fps run it could be spot on 3 pictures and beeing set to 5000k for one. I shoot in raw, so I havent bothered with it.

12-19-2009, 02:29 PM	#9
Marc Sabatella Veteran Member Join Date: Sep 2006 Location: Denver, CO Photos: Gallery Posts: 10,685	AWB is always just a guess based on the colors the cameras sees. If nything at all changes about the scene - even the slightest thing it could affect the results. Here, the framing and or hands moved so that the ratio of skin to plate changed; I'm guessing that's what did it - although I'm surprised it made as much difference as it did. Basically, if you care about WB, you don't let the camera choose it for you. AWB is fine if you shoot RAW and can correct it later, but if you shoot JPEG and differences like this matter, then you need to set it yourself, because AWB is really just a guessing game.

12-20-2009, 08:59 AM	#10
planedriver Inactive Account Join Date: Feb 2009 Location: Velence, Hungary Posts: 664 Original Poster	Thanks for the feedback! Andras

12-20-2009, 09:13 AM	#11
Eruditass Veteran Member Join Date: Jul 2009 Photos: Gallery Posts: 2,207	I've also had this problem, like it was jumping between strong and weak tungsten (or something else) where the source of lighting was only tungsten and did not change. Didn't notice it with a K2000 or K10D, I'd be interested to see if most K-x users experience this or if K-7 users do to. Mildly annoying, but I shoot in RAW.

12-20-2009, 09:28 AM	#12
planedriver Inactive Account Join Date: Feb 2009 Location: Velence, Hungary Posts: 664 Original Poster	Originally posted by Eruditass Mildly annoying, but I shoot in RAW. I shoot RAW too-yes it's mildly annoying. I'm just rather curious. It's good to know what's going on in your camera. Also noticed that shooting in the house under natural lighting conditions (so the windows are the light sources)some areas where the light is reflected ( for example floor) can look very cold (blue) on the picture. Andras

01-01-2010, 08:39 PM	#13
Optical Illusion Forum Member Join Date: Nov 2009 Location: Kern County California Photos: Albums Posts: 70	I was outside under a cloudy sky today practicing with the K-x and an M50 1.7 lens. I was taking shots of some green painted wood and was not looking at each shot. Then I noticed one where the green looked almost brown! What? I thought the LCD colors were off or something - I switched from AWB to 'sunlight' and the color looked correct. Still I was surprised and dissappointed at how far off Auto was...outside! Does that mean I really can't trust it? I have never really worried about it on P&S camras. Should I carry around a piece of white copy paper with me? I thought this tended to be more of an issue inside under artificial light.

01-02-2010, 10:38 AM	#14
Marc Sabatella Veteran Member Join Date: Sep 2006 Location: Denver, CO Photos: Gallery Posts: 10,685	It's an issue with an camera any time a scene is dominated by one color. The camera sees that color and has absolutely no wy of determining if the objects in the scene really are that color or if it just looks that way because the light is that color. No matter which way it guesses, it is going to be right sometimes and wrong sometimes.

K-x White-balance question

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