Canon's AWB = Purple?

I got my first (and perhaps only) major snow of the year today... yes, that amount of snow is considered a "major snow" in Atlanta. At any rate, I got out the G1 and took a few pictures. The one below made use of Auto White Balance:



In this next one I manually calibrated white balance to the back of the Canon manual:



To me, it is VERY clear that the photo taken using AWB has a distinct purple tint. The one taken using Custom WB has colors that are quite true to life.

Any comments or ideas (other than, "use Custom WB all the time")?

Thanks.

Any time software does a color balance, it looks at some portion of the image and tries to make the summation or average or some other function of the image equal to white. If the real world is mostly blue, the result will be a yellow shift, if the real world is mostly yellow the resulting picture will have a blue cast.

In your snowy scene the snow has equal amounts of red and green but more blue which means that the camera saw a world with a lot of yellow. Looking at the yellowish leaves in left center, I can imagine what happened.

Chris Kennedy said:

I got my first (and perhaps only) major snow of the year today...
yes, that amount of snow is considered a "major snow" in Atlanta.
At any rate, I got out the G1 and took a few pictures. The one
below made use of Auto White Balance:



In this next one I manually calibrated white balance to the back of
the Canon manual:



To me, it is VERY clear that the photo taken using AWB has a
distinct purple tint. The one taken using Custom WB has colors that
are quite true to life.

Any comments or ideas (other than, "use Custom WB all the time")?

Thanks.

Click to expand...

Can I suggest the author Dennis P. Curtin, he explains how digital metering of visible light works and that awb gets fooled "some of the time". Previewing your metering on the lcd usually helps in processing a shot.

Ned said:

In your snowy scene the snow has equal amounts of red and green but
more blue which means that the camera saw a world with a lot of
yellow. Looking at the yellowish leaves in left center, I can
imagine what happened.

Chris Kennedy said:

I got my first (and perhaps only) major snow of the year today...
yes, that amount of snow is considered a "major snow" in Atlanta.
At any rate, I got out the G1 and took a few pictures. The one
below made use of Auto White Balance:



In this next one I manually calibrated white balance to the back of
the Canon manual:



To me, it is VERY clear that the photo taken using AWB has a
distinct purple tint. The one taken using Custom WB has colors that
are quite true to life.

Any comments or ideas (other than, "use Custom WB all the time")?

Thanks.

Click to expand...

Click to expand...

Vic said:

Can I suggest the author Dennis P. Curtin, he explains how digital
metering of visible light works and that awb gets fooled "some of
the time". Previewing your metering on the lcd usually helps in
processing a shot.

Click to expand...

If you don't mind, could you please elaborate on specifically which of Mr. Curtin's books we should read? Are his works available online?

Many thanks,

--Sergey

Hi Sergey

If you go to amazon.com, you can search by author and you will get a list for sale. He has written lessons on several digicams. The canon books discuss how awb settings work clearly...

Sergey Goldgaber said:

Vic said:

Can I suggest the author Dennis P. Curtin, he explains how digital
metering of visible light works and that awb gets fooled "some of
the time". Previewing your metering on the lcd usually helps in
processing a shot.

Click to expand...

If you don't mind, could you please elaborate on specifically which
of Mr. Curtin's books we should read? Are his works available
online?

Many thanks,

--Sergey

Click to expand...

Hi Chris,

Your first picture looks just like a snow picture I took. Purple Snow! It ruined an otherwise great picture that I wanted to use for my Christmas cards this year I also used the AWB. But I'm new to all of this. Not very knowledgable about photography. So when I took the picture I was so proud of myself just to be using the AWB in the first place. I'm not sure what I have to do to correct this. I have started using the other WB settings- cloudy, sunny, etc. Is that what you're talking about? I'm a true newby to all of this. Any advice will help. Thanks! Shar

Vic said:

Sergey Goldgaber said:

Vic said:

Can I suggest the author Dennis P. Curtin, he explains how digital
metering of visible light works and that awb gets fooled "some of
the time". Previewing your metering on the lcd usually helps in
processing a shot.

Click to expand...

If you don't mind, could you please elaborate on specifically which
of Mr. Curtin's books we should read? Are his works available
online?

Many thanks,

--Sergey

Click to expand...

Click to expand...

This I'm afraid is a very good example of why I just cannot come to terms with the glowing admiration for the G1 expressed here nor why the very definite common problem is not encountered most of the time or to anything like the same degree in many other cameras which are certainly in the same category as the G1. It is easy enough to come up with technical explanations but it just doesn't happen in others. It seems continually that users are expected to make adjustments or allowances for what the camera should do quite properly itself. What IS AutoWB if not just that. Variations in the overall scene are just no excuse. The second shot is what I would expect as a far better attempt to cope with the scene but surely the camera should do that - why put on AiutoWB if it doesn't do its job. As indicated here, it just leads to big user disappointment for which often there may be no second chance.

Eric

Chris Kennedy said:

I got my first (and perhaps only) major snow of the year today...
yes, that amount of snow is considered a "major snow" in Atlanta.
At any rate, I got out the G1 and took a few pictures. The one
below made use of Auto White Balance:



In this next one I manually calibrated white balance to the back of
the Canon manual:



To me, it is VERY clear that the photo taken using AWB has a
distinct purple tint. The one taken using Custom WB has colors that
are quite true to life.

Any comments or ideas (other than, "use Custom WB all the time")?

Thanks.

Click to expand...

Snowy scenes seem to be a problem with AWB - but on the other hand the snow gives us plenty of nice white to balance against. The process is easy:

The point of custom WB is to clarify to the camera what is truly white in a scene. In this case go to the WB settings, select custom WB, center the shot on some snow and press . Refer to page 65 in the manual for detailed instauctions.

I have found that AWB seems fine on outdoor sunny to partly cloudy settings. I mainly use custom WB for snowy and indoor flash shots (although since I got my 420EX - WB: Flash seems to do a very good job).

Shar said:

Vic said:

Sergey Goldgaber said:

Vic said:

Can I suggest the author Dennis P. Curtin, he explains how digital
metering of visible light works and that awb gets fooled "some of
the time". Previewing your metering on the lcd usually helps in
processing a shot.

Click to expand...

If you don't mind, could you please elaborate on specifically which
of Mr. Curtin's books we should read? Are his works available
online?

Many thanks,

--Sergey

Click to expand...

Click to expand...

Click to expand...

Thanks Marty, I'll give it a try!

Marty said:

The point of custom WB is to clarify to the camera what is truly
white in a scene. In this case go to the WB settings, select
custom WB, center the shot on some snow and press . Refer to page
65 in the manual for detailed instauctions.

I have found that AWB seems fine on outdoor sunny to partly cloudy
settings. I mainly use custom WB for snowy and indoor flash shots
(although since I got my 420EX - WB: Flash seems to do a very good
job).

Shar said:

Vic said:

Sergey Goldgaber said:

Vic said:

Can I suggest the author Dennis P. Curtin, he explains how digital
metering of visible light works and that awb gets fooled "some of
the time". Previewing your metering on the lcd usually helps in
processing a shot.

Click to expand...

If you don't mind, could you please elaborate on specifically which
of Mr. Curtin's books we should read? Are his works available
online?

Many thanks,

--Sergey

Click to expand...

Click to expand...

Click to expand...

Click to expand...

Marty said:

Snowy scenes seem to be a problem with AWB - but on the other hand
the snow gives us plenty of nice white to balance against. The
process is easy:

The point of custom WB is to clarify to the camera what is truly
white in a scene. In this case go to the WB settings, select
custom WB, center the shot on some snow and press . Refer to page
65 in the manual for detailed instauctions.

Click to expand...

And since there always won't be all that nice white snow around to set the WB off of, I think I am going to visit the local home improvement store, go to the kitchen and bath section, and grab a few white formica sample chips to keep on my keychain or on the camera strap...I'm gonna be ready! LOL, Why not go custom all the time!?..a couple extra seconds well spent toward a better shot, IMHO.

Member said:

I have found that AWB seems fine on outdoor sunny to partly cloudy
settings. I mainly use custom WB for snowy and indoor flash shots
(although since I got my 420EX - WB: Flash seems to do a very good
job).

Click to expand...

I agree. It seems like setting the custom white balance would be worth it. I understand pointing it at something white to get the settings for snow. But how do you set it in other situations? How do you choose what to point it at for the setting?

Lynn said:

Marty said:

Snowy scenes seem to be a problem with AWB - but on the other hand
the snow gives us plenty of nice white to balance against. The
process is easy:

The point of custom WB is to clarify to the camera what is truly
white in a scene. In this case go to the WB settings, select
custom WB, center the shot on some snow and press . Refer to page
65 in the manual for detailed instauctions.

Click to expand...

And since there always won't be all that nice white snow around to
set the WB off of, I think I am going to visit the local home
improvement store, go to the kitchen and bath section, and grab a
few white formica sample chips to keep on my keychain or on the
camera strap...I'm gonna be ready! LOL, Why not go custom all the
time!?..a couple extra seconds well spent toward a better shot,
IMHO.

Lynn32671 said:

I have found that AWB seems fine on outdoor sunny to partly cloudy
settings. I mainly use custom WB for snowy and indoor flash shots
(although since I got my 420EX - WB: Flash seems to do a very good
job).

Click to expand...

Click to expand...

After having just read how to set custom WB in the Canon book and here on this post, from what I understand I guess that something "white" is the way to do it no matter what the situation. Please correct me if I'm wrong. Boy, have I got a lot to learn. But that's why I chose this camera!

Shar said:

Lynn said:

Marty said:

Snowy scenes seem to be a problem with AWB - but on the other hand
the snow gives us plenty of nice white to balance against. The
process is easy:

The point of custom WB is to clarify to the camera what is truly
white in a scene. In this case go to the WB settings, select
custom WB, center the shot on some snow and press . Refer to page
65 in the manual for detailed instauctions.

Click to expand...

And since there always won't be all that nice white snow around to
set the WB off of, I think I am going to visit the local home
improvement store, go to the kitchen and bath section, and grab a
few white formica sample chips to keep on my keychain or on the
camera strap...I'm gonna be ready! LOL, Why not go custom all the
time!?..a couple extra seconds well spent toward a better shot,
IMHO.

Shar said:

I have found that AWB seems fine on outdoor sunny to partly cloudy
settings. I mainly use custom WB for snowy and indoor flash shots
(although since I got my 420EX - WB: Flash seems to do a very good
job).

Click to expand...

Click to expand...

Click to expand...

I think everybody's gone into hiding on this embrassing topic. This is what true AutoWB is really about ... full Auto, no after-fiddling , just right for fringing if at all ... wonder what the G1 would do with this ??

I defenitely agree with you. I used two different cameras in the past a sony dsc-s70 and the nikon 990. I think that the G1 does over more flexibility but there are those times that I want to be able to shoot and not fuzz around with the settings. I believe that canon is greatly to blame since they released a camera that does everyting but auto. I don't want to start a flame over this . I am just explaining it how it really is. I do own a G1 and probably will hang to it till something better come a long. I know that no digital camera is flawless, but from my own experiences and from those I have seen here canon did not put their all out effort on this camera.

Eric said:

Eric

Chris Kennedy said:

I got my first (and perhaps only) major snow of the year today...
yes, that amount of snow is considered a "major snow" in Atlanta.
At any rate, I got out the G1 and took a few pictures. The one
below made use of Auto White Balance:



In this next one I manually calibrated white balance to the back of
the Canon manual:



To me, it is VERY clear that the photo taken using AWB has a
distinct purple tint. The one taken using Custom WB has colors that
are quite true to life.

Any comments or ideas (other than, "use Custom WB all the time")?

Thanks.

Click to expand...

Click to expand...

What camera took that photo, Eric? I get the impression that it was not a G1...

Eric said:

I think everybody's gone into hiding on this embrassing topic. This
is what true AutoWB is really about ... full Auto, no
after-fiddling , just right for fringing if at all ... wonder what
the G1 would do with this ??

Click to expand...

Chris -

It was my favourite 'pocket camera' the little Oly. Have both 2020 then a 3000 bought because I liked it so much and imagined the 3000 would be even better. It isn't THAT much different for most things exceptthe f2 lens on the 2020 can be useful in really low light shooting. This I think was with the 2020 , full Auto. I did some more in same location with the 3000 but that was a better , slightly blue sky day, which I why I'm sure this was a 2020 one - much more overcast as you'll notice. In fact the last few I shot on that occasion were as it started to rain but in the shots you'd hardly notice, certainly no color cast. I do so wish I could get to try a G1 but they are scarce as snow in the desert round here. I just keep reading so much on so many different problems I am no way going to commit myself one way or other until I use it. I know a lot do complain but in fact I don't think they have the setup right to start with. The thing that bothers me most though is this AutoWB business, believe me, on the Oly it is absolutely and utterly reliable in ANY situation. I'm not incapable of making adjustments but (a) just don't want to now (b) think the camera should be capable in most cases of doing it anyway.

Eric

Chris Kennedy said:

Eric said:

I think everybody's gone into hiding on this embrassing topic. This
is what true AutoWB is really about ... full Auto, no
after-fiddling , just right for fringing if at all ... wonder what
the G1 would do with this ??

Click to expand...

Click to expand...

The photo looks fine to me. The second one looks better, and looking at both photos together I can see that the first one has a purple cast relative to the second one, but I honestly would not have noticed the
"problem" had I only been shown the first (auto) photo.

FWIW, I am viewing with a gamma of about 2.2 on a Studioworks 995E monitor, with the monitor set to 6500K. No calibration other than manual brightness & contrast adjustment.

Greg.
p.s I have no reason to defend Canon - I am an Olympus owner.

nice pic Eric...English cemetary? looking at it I see lotsa greeeen, was it really that green?...though it's a beautiful color...the results however automatic we wish it to be...processing really good original digital photos still depends in part on the accuracy with which we expose an image to the color of light at the time of exposure by deciding when to use wb overide...and how our camera handles color balance...
i'm still learning so now i'm gonna hide

Eric said:

I think everybody's gone into hiding on this embrassing topic. This
is what true AutoWB is really about ... full Auto, no
after-fiddling , just right for fringing if at all ... wonder what
the G1 would do with this ??

Click to expand...

Vic -

Yes, it really was very much that green. I seem to remember I gave the pic just a slight tweak in PSPro, mostly just a touch of Unsharp Mask I think, but the green was mostly there. We've just gone through a very mild and VERY wet Autum period here and so the greenery has stayed with us remarkably well. Believe it or not we still have geraniums in green and even the odd flower. The attraction of this of a series of pics is that it was taken in my old home town and the churchyard containing these old ruins also contains the present 'newer' church that has attached to it just 50 or so yards away my original first primary school. Quite a sentimental visit in many ways.

Eric

Vic said:

Eric said:

I think everybody's gone into hiding on this embrassing topic. This
is what true AutoWB is really about ... full Auto, no
after-fiddling , just right for fringing if at all ... wonder what
the G1 would do with this ??

Click to expand...

Click to expand...