Reading mode: Light Dark

30D and White balance issue

Go to last post
This is a shot under a 40 watt tungsten. AWB. No PP except resizing.
The subject is white with black grid lines and texts.

1 - shot at 70mm



2 - shot at 17mm



I have not used my 30D extensively under different lighting condition but I am quite satisfied almost all the time with the WB under AWB setting.

tinc
 
saynomore said:
By the way, I wonder where is everybody, I hardly know anyone in
this forum anymore, I guess many of you are 30D new users, just
like I was about 18 months ago. Hello.

Well, your problem is not white balance, it is exposure. If the
colors are just shifting darker and lighter white to gray, etc, it
is not white balance. Another thing to take into account is that
when taking RAW shots (which you should if you're doing a studio
environment) then white balance is totally manageable after the
fact (and I mean TOTALLY, as in even more than "before the fact")
in any RAW converter.
Click to expand...
I am not sure if it is not the WB problem. I shot everything in RAW and I can't, at my skill level, seem to get the grey cast disappear with all sorts of adjustments ranging from exposure, white balance, levels to each color channel and whatever options are there in PPD, Camera RAW 3.3 and Silkypix Developer Studio 2.0E. Or maybe I just don't know what I am doing :-)
saynomore said:
That said, to your real problem. It depends on what metering mode
you are using. If you use evaluative (default) which you are
seemingly using, then the camera will calculate an exposure based
primarily on the focus point selected (in Auto-focus mode) and
secondarily in everything else in the frame, which is divided by
areas. It applies some proprietary mysterious algorithms (though
not magic) to do that. In your normal scene, it wouldn't have much
trouble, but it is not perfect, as magic would probably be.

When you have a very bright background that occupies a lot of the
scene, the camera in evaluative metering will try to expose
whatever it can evenly, so you will get grayish background, as the
camera doesn't know it's supposed to be white. Consequently, you
will get an underexposed subject as well. The remedy for this is
just use exposure compensation, that's what it's for. The camera
can't tell any brightness level of any object (again, not magic),
so it just assumes the subject is some level of gray, and then
applies the environment's brightness to come up with something.

You can also try other different exposure modes, it would make it
easier. Partial only takes into account whatever is in the 9% area
(the center circle) and takes that and only that to be some kind of
neutral gray. So if your subject fills that circle, the background
won't affect the metering at all. You'd probably need to use some
exposure compensation as well, depending on the brightness of your
subject.

Spot metering allows you to do the same on a smaller area of 3.5%
around the center focus point. This might be more useful. Try this
with different exposure compensations, and you will be fine.

If you're gonna be trying any of these methods, ir your subject is
not in the center of the frame, you will need to shoot either M
mode (recommended) taking into account exposure metering
deviations, or you will need to meter the subject with the center
area/spot, and press the exposure lock ( ) button and then
recompose. Exposure is not locked by half pressing the shutter
button in these modes as far as I know.

Another metering mode is center weighed, but you can do away with it.
Click to expand...
As stated in my first mail I had tried ALL meterings, Av and manual mode, with compensation to shoot it to right, left etc. For the list of the things I tried please refer to the first message of this thread. All those are done in a "controlled enviornment" with nothing but the camera setting changes. After all it shouldn't affect the RAW file if it can be PP corrected?! Will you or anyone be interested in giving the RAW files a shoot to your taste and show me your magic hands? All I want is a little white color, not balls, at the back:-)

Oh well I think I am getting a bit tired with this thing now. Thanks for your inputs. I am still waiting for someone to come up with something white with the test.

Cheers

--
Just hit that little white ball and search hard for it.
 
fasttempo123 said:
I am not sure if it is not the WB problem. I shot everything in RAW
and I can't, at my skill level, seem to get the grey cast disappear
with all sorts of adjustments ranging from exposure, white balance,
levels to each color channel and whatever options are there in PPD,
Camera RAW 3.3 and Silkypix Developer Studio 2.0E. Or maybe I just
don't know what I am doing :-)
Click to expand...
Well, it can be both, but it definitely is exposure. There is no "gray cast" Grey is white, olny darker. White balance color casts are colored. These are some pics I improvised a while ago at work for a friend.

This first one did have a yellow color cast and was underexposed.



Totally and easily fixable in RAW conversion.



These were just underexposed, and also saturation was bumped.








fasttempo123 said:
fasttempo123 said:
That said, to your real problem. It depends on what metering mode
you are using. If you use evaluative (default) which you are
seemingly using, then the camera will calculate an exposure based
primarily on the focus point selected (in Auto-focus mode) and
secondarily in everything else in the frame, which is divided by
areas. It applies some proprietary mysterious algorithms (though
not magic) to do that. In your normal scene, it wouldn't have much
trouble, but it is not perfect, as magic would probably be.

When you have a very bright background that occupies a lot of the
scene, the camera in evaluative metering will try to expose
whatever it can evenly, so you will get grayish background, as the
camera doesn't know it's supposed to be white. Consequently, you
will get an underexposed subject as well. The remedy for this is
just use exposure compensation, that's what it's for. The camera
can't tell any brightness level of any object (again, not magic),
so it just assumes the subject is some level of gray, and then
applies the environment's brightness to come up with something.
Click to expand...
Click to expand...
fasttempo123 said:
fasttempo123 said:
You can also try other different exposure modes, it would make it
easier. Partial only takes into account whatever is in the 9% area
(the center circle) and takes that and only that to be some kind of
neutral gray. So if your subject fills that circle, the background
won't affect the metering at all. You'd probably need to use some
exposure compensation as well, depending on the brightness of your
subject.

Spot metering allows you to do the same on a smaller area of 3.5%
around the center focus point. This might be more useful. Try this
with different exposure compensations, and you will be fine.

If you're gonna be trying any of these methods, ir your subject is
not in the center of the frame, you will need to shoot either M
mode (recommended) taking into account exposure metering
deviations, or you will need to meter the subject with the center
area/spot, and press the exposure lock ( ) button and then
recompose. Exposure is not locked by half pressing the shutter
button in these modes as far as I know.

Another metering mode is center weighed, but you can do away with it.
Click to expand...
Click to expand...
fasttempo123 said:
As stated in my first mail I had tried ALL meterings, Av and manual
mode, with compensation to shoot it to right, left etc. For the
list of the things I tried please refer to the first message of
this thread. All those are done in a "controlled enviornment" with
nothing but the camera setting changes. After all it shouldn't
affect the RAW file if it can be PP corrected?! Will you or anyone
be interested in giving the RAW files a shoot to your taste and
show me your magic hands? All I want is a little white color, not
balls, at the back:-)
Click to expand...
I did read your mail, I guess I missed some details. In cany case, how did you try spot and partial metering? Was your subject covering the entire metering area? Did you use the exposure lock button, or did you not recompose? You still would have needed to use exposure compensation. Since you were shooting in M mode, that means the little arrow shouldn't have been right on the middle, but left or right depending on how much you wanted to compensate.

WB is totally correctable in RAW, but if you used bad light, then it's another thing. From your examples I see it wasn't that bad lighting. Exposure is another thing. You only get a bit more exposure latitude in RAW, it is not totally correctable.

Send me your file(s) to: [email protected]
 
tinc said:
This is a shot under a 40 watt tungsten. AWB. No PP except resizing.
The subject is white with black grid lines and texts.

1 - shot at 70mm



2 - shot at 17mm



I have not used my 30D extensively under different lighting
condition but I am quite satisfied almost all the time with the WB
under AWB setting.

tinc
Click to expand...
Tinc,

I am glade you are happy with your 30D and I am trying hard to do the same right now.

Can you try to process your images so that it becomes white instead of tungstenized?

Maybe I didn't put it properly before but the white color that I have been talking about and striving for is like the white color at the corner of my samples. Not the white color with color cast. To my eyes the inside of my soft tent has been set up as white as snow when lightup, well almost:-). I have two white foamy board in front and at the back of the object reflecting three 120Watts 6500k lights between the boards at an approximately 40x40x40cm space. The only dark area is thte size of my lens hood diameter.

--
Just hit that little white ball and search hard for it.
 
It really is an exposure problem. On both your pics the grey areas have R, G and B number which are quite equal: they are [very close to] neutral grey. In Camera RAW you move the exposure slider to the right, and they'll become white [and your objects will become brighter and livelier]

In this context white, grey and black are not considered colors, there is no such thin as white color or a grey cast. Tinc's shot has a color cast, from the Tungsten light. If you take his jpg into PS you can (with levels auto) easily remove that cast (making the yellowish paper white)

R
fasttempo123 said:
I am not sure if it is not the WB problem. I shot everything in RAW
and I can't, at my skill level, seem to get the grey cast disappear
with all sorts of adjustments ranging from exposure, white balance,
levels to each color channel and whatever options are there in PPD,
Camera RAW 3.3 and Silkypix Developer Studio 2.0E. Or maybe I just
don't know what I am doing :-)
fasttempo123 said:
That said, to your real problem. It depends on what metering mode
you are using. If you use evaluative (default) which you are
seemingly using, then the camera will calculate an exposure based
primarily on the focus point selected (in Auto-focus mode) and
secondarily in everything else in the frame, which is divided by
areas. It applies some proprietary mysterious algorithms (though
not magic) to do that. In your normal scene, it wouldn't have much
trouble, but it is not perfect, as magic would probably be.

When you have a very bright background that occupies a lot of the
scene, the camera in evaluative metering will try to expose
whatever it can evenly, so you will get grayish background, as the
camera doesn't know it's supposed to be white. Consequently, you
will get an underexposed subject as well. The remedy for this is
just use exposure compensation, that's what it's for. The camera
can't tell any brightness level of any object (again, not magic),
so it just assumes the subject is some level of gray, and then
applies the environment's brightness to come up with something.

You can also try other different exposure modes, it would make it
easier. Partial only takes into account whatever is in the 9% area
(the center circle) and takes that and only that to be some kind of
neutral gray. So if your subject fills that circle, the background
won't affect the metering at all. You'd probably need to use some
exposure compensation as well, depending on the brightness of your
subject.

Spot metering allows you to do the same on a smaller area of 3.5%
around the center focus point. This might be more useful. Try this
with different exposure compensations, and you will be fine.

If you're gonna be trying any of these methods, ir your subject is
not in the center of the frame, you will need to shoot either M
mode (recommended) taking into account exposure metering
deviations, or you will need to meter the subject with the center
area/spot, and press the exposure lock ( ) button and then
recompose. Exposure is not locked by half pressing the shutter
button in these modes as far as I know.

Another metering mode is center weighed, but you can do away with it.
Click to expand...
As stated in my first mail I had tried ALL meterings, Av and manual
mode, with compensation to shoot it to right, left etc. For the
list of the things I tried please refer to the first message of
this thread. All those are done in a "controlled enviornment" with
nothing but the camera setting changes. After all it shouldn't
affect the RAW file if it can be PP corrected?! Will you or anyone
be interested in giving the RAW files a shoot to your taste and
show me your magic hands? All I want is a little white color, not
balls, at the back:-)

Oh well I think I am getting a bit tired with this thing now.
Thanks for your inputs. I am still waiting for someone to come up
with something white with the test.

Cheers

--
Just hit that little white ball and search hard for it.
Click to expand...
 
If you just wanted to get a white background, you can just do levels or curves adjustment. Just a couple of clicks.





However, this is not ideal, the ideal thing would be to expose properly in the first place. You mentioned you needed the gray to be white. I did that, but if you want a white background, use a white background!

Gray cards are only for testing exposure, then you get the gray out of the scene and expose with the same settings the gray card alone (with nothing else in the metering area) got you.
 
you said before:

:I might not have put it clearly in my previous message but my "white card" is whatever inside of the tent minues the little product which was removed when taken for custom WB. The "white card" shot is dark grey when at the right exposure. With + compensation the shot goes to light grey. Then this is going to ruin your consequential shoots anyway as everything is bound to be over exposed.

I think here belies your problem. Your reasoning is wrong. If you expose a white subject filling the metering area wth it, the camera's metering will think it's gray, and underexpose a bit. If you then "over" expose as to make it its real brightness level (white) then you will get correctly exposed images with those very same settings. Gray cards are gray so you don't need to do this overexposure to get things right. The camera will correctly assume the subject is a neutral gray tone, and will expose properly.

You have to understand exposure compensation is not to compensate for any error in metering, it is there because it is a fact of life. Cameras can't just guess correctly the brightness level of any object you throw at them. That's why gray cards exist.
 
Hi fasttempo123,

The color tone of the sample shot from my previous post was what I would have expected based on the current lighting condition (tungsten lighting). If say I would like to see at least the original color of my subject I would just use levels in Photoshop.

The below image is the same as my previous sample processed in Photoshop using levels.



That is almost close enough to the white I know. Perhaps a little more tweaking in PS would make it a little accurate if I shot RAW (this was JPEG). But this is as far as my knowledge goes if this does not answer your questions. :)
tinc
 
saynomore said:
you said before:

:I might not have put it clearly in my previous message but my "white card" is whatever inside of the tent minues the little product which was removed when taken for custom WB. The "white card" shot is dark grey when at the right exposure. With + compensation the shot goes to light grey. Then this is going to ruin your consequential shoots anyway as everything is bound to be over exposed.

I think here belies your problem. Your reasoning is wrong. If you
expose a white subject filling the metering area wth it, the
camera's metering will think it's gray, and underexpose a bit. If
you then "over" expose as to make it its real brightness level
(white) then you will get correctly exposed images with those very
same settings. Gray cards are gray so you don't need to do this
overexposure to get things right. The camera will correctly assume
the subject is a neutral gray tone, and will expose properly.

You have to understand exposure compensation is not to compensate
for any error in metering, it is there because it is a fact of
life. Cameras can't just guess correctly the brightness level of
any object you throw at them. That's why gray cards exist.
Click to expand...
Hello saynomore,

thank you for your samples and follow up explainations of what merters are all about. I am here to find a workable solution as I stated I still believe it the problem of the guy behind the camera. However I am not look for something like clicking the white pointer at the grey background to get it white with levels. Or auto level to get something like white etc. In addition, I have to shoot 100s of photos so individual labour intensive care of each photo/most of them are not practical as I do have a time limit on the assigment. I know you didn't mean white pointer is the solution.

With all due respect, some of your samples look over exposed to my taste and the histograms seem to agree with me. I can't post other's work here but if you check out web sites like tiffany etc you will know what I mean by white without over exposure. Their images look natural, comfortable and bright without harshness( a result of exposure). Make no mistake I am not try to get that sort of qaulity with the equipment in hand. However I try whatever I can and hopefully 30D can to get the best result possible. Checking for any over exposed area of the subject for each of my shot and try to shoot as right as it permits without clicking the right are some of the standard thing I do for my shots' basic QA.

I have sent you a raw file for process.

--Just hit that little white ball and search hard for it.
 
I guess then you want to have a white background, but not THAT white? If my images are or aren't overexposed is not the matter, but just how to calculate a decent exposure. Basically, if you have a white object, like a card, you need to make a test shot where the card will appear white, the same color as it normally is. It will tend to appear gray if it fills all the frame, so you may need to do some compensation.

The very same exposure settings you get to get the white card white should work with any other objects in the same lighting. Usually though you'd wanna overexpose a bit without clipping. This is the hard thing to do. Then pull back some of the overexposure in RAW conversion. But this is another matter.
 
But I would do the same with it, just adjust exposure (brightness in DPP) to make it a bit brighter to the point that the background pleases you. But this has a limit, you can only go so far. The ideal solution would be to get exposure right when shooting.

If you just wanna make the background white, make sure it's white. If you are using a white card, overexpose as for the card to be white in the pic. Then use the very same settings for the actual pics. You don't need to worry about the object being overexposed. It won't. The background will be white as you metered it, but because the object is not white, it will not be blown. You have to consider the relative brightness between the background and the object. If you use a gray card, then don't overexpose. The card should look gray in the pic.

So that would be the solution unless I'm really not getting what you need. Feel free to keep asking though, now I'm curious.
saynomore said:
I guess then you want to have a white background, but not THAT
white? If my images are or aren't overexposed is not the matter,
but just how to calculate a decent exposure. Basically, if you have
a white object, like a card, you need to make a test shot where the
card will appear white, the same color as it normally is. It will
tend to appear gray if it fills all the frame, so you may need to
do some compensation.

The very same exposure settings you get to get the white card white
should work with any other objects in the same lighting. Usually
though you'd wanna overexpose a bit without clipping. This is the
hard thing to do. Then pull back some of the overexposure in RAW
conversion. But this is another matter.
Click to expand...
 
Hello Tinc,

Thank you for your effort and help. You have been very nice.

Jewelry is a hard subject and together with a new tool is really having me all over the place right now.

Cheers
tinc said:
Hi fasttempo123,

The color tone of the sample shot from my previous post was what I
would have expected based on the current lighting condition
(tungsten lighting). If say I would like to see at least the
original color of my subject I would just use levels in Photoshop.

The below image is the same as my previous sample processed in
Photoshop using levels.



That is almost close enough to the white I know. Perhaps a little
more tweaking in PS would make it a little accurate if I shot RAW
(this was JPEG). But this is as far as my knowledge goes if this
does not answer your questions. :)
tinc
Click to expand...
--
Just hit that little white ball and search hard for it.
 
I am sending you the frog raw file where you can see the dark grey cast on the pink string. That is what I am talking about and trying to get rid off.

As the result the overall image looks dirty and lifeless. I certainly appreciate your effort and help but I just can't get it right with exposing to right. I have tried it as I stated in my first message. If you look at the raw files the exposures are to the right and they all have +2/3 compensation in it. I can shoot it over easily but that is not what I want.
saynomore said:
If you just wanna make the background white, make sure it's white.
If you are using a white card, overexpose as for the card to be
white in the pic. Then use the very same settings for the actual
pics. You don't need to worry about the object being overexposed.
It won't. The background will be white as you metered it, but
because the object is not white, it will not be blown. You have to
consider the relative brightness between the background and the
object. If you use a gray card, then don't overexpose. The card
should look gray in the pic.

So that would be the solution unless I'm really not getting what
you need. Feel free to keep asking though, now I'm curious.
saynomore said:
I guess then you want to have a white background, but not THAT
white? If my images are or aren't overexposed is not the matter,
but just how to calculate a decent exposure. Basically, if you have
a white object, like a card, you need to make a test shot where the
card will appear white, the same color as it normally is. It will
tend to appear gray if it fills all the frame, so you may need to
do some compensation.

The very same exposure settings you get to get the white card white
should work with any other objects in the same lighting. Usually
though you'd wanna overexpose a bit without clipping. This is the
hard thing to do. Then pull back some of the overexposure in RAW
conversion. But this is another matter.
Click to expand...
Click to expand...
--
Just hit that little white ball and search hard for it.
 
fasttempo123 said:
I am sending you the frog raw file where you can see the dark grey
cast on the pink string. That is what I am talking about and trying
to get rid off.
As the result the overall image looks dirty and lifeless. I
certainly appreciate your effort and help but I just can't get it
right with exposing to right. I have tried it as I stated in my
first message. If you look at the raw files the exposures are to
the right and they all have +2/3 compensation in it. I can shoot it
over easily but that is not what I want.
Click to expand...
Ok, I see your trouble now. Actually if you have a lot of white in your frame, you will see a a lot of info at the right of your histogram. That is not "exposure to the right". Exposure to the right means the values of your subject, which can be just a small spike in the histogram (depending on the subject/background size ratio) should tend to be to the right. Which means that the white background values will tend to be blown. Again, this is a very precise way to maximize your dynamic range and minimize noise, you need to make it right since the beginning.

RAW allows for about 1 stop more in the highlights, so you may have to calculate for the white background to be just about 1 stop blown if you wanna pull back the detail in RAW.

So you see a gray cast in the pic? I see it in the pics you posted before, but then on the fixed jpegs I posted after that I don't see it. I think it is because now the gray turned into white. In cany case the gray should be a combination of underexposure and color curves.

This one has the background slightly darker than the previous jpeg I posted. It looks better because I coverted it from RAW.



I got rid of the color cast I think. But still, I think your main problem is on getting correct exposures right off the bat.

This is the previous one.



And just for comparison's sake, this is yours. Hope you don't mind me linking from your site, I don't have it anymore. Also, you might need to do a sensor clean, I think I see a dust spot.

 
saynomore said:
Ok, I see your trouble now. Actually if you have a lot of white in
your frame, you will see a a lot of info at the right of your
histogram.
Click to expand...
Here I meant you will see a spike at the right, which would mean you have a lot of pixels of just that brightness (close to white). But that's not your subject. That spike, which is the background in this case, should be just a bit overblown, for it to be "exposure to the right".
saynomore said:
That is not "exposure to the right". Exposure to the
right means the values of your subject, which can be just a small
spike in the histogram (depending on the subject/background size
ratio) should tend to be to the right. Which means that the white
background values will tend to be blown. Again, this is a very
precise way to maximize your dynamic range and minimize noise, you
need to make it right since the beginning.
Click to expand...
 
OK, I think I just can't get myself expressed well enough. Here is another image I shot earlier with the level of details that I want for my shots. This one is obviously a much easier object to shoot.


saynomore said:
fasttempo123 said:
I am sending you the frog raw file where you can see the dark grey
cast on the pink string. That is what I am talking about and trying
to get rid off.
As the result the overall image looks dirty and lifeless. I
certainly appreciate your effort and help but I just can't get it
right with exposing to right. I have tried it as I stated in my
first message. If you look at the raw files the exposures are to
the right and they all have +2/3 compensation in it. I can shoot it
over easily but that is not what I want.
Click to expand...
Ok, I see your trouble now. Actually if you have a lot of white in
your frame, you will see a a lot of info at the right of your
histogram. That is not "exposure to the right". Exposure to the
right means the values of your subject, which can be just a small
spike in the histogram (depending on the subject/background size
ratio) should tend to be to the right. Which means that the white
background values will tend to be blown. Again, this is a very
precise way to maximize your dynamic range and minimize noise, you
need to make it right since the beginning.

RAW allows for about 1 stop more in the highlights, so you may have
to calculate for the white background to be just about 1 stop blown
if you wanna pull back the detail in RAW.

So you see a gray cast in the pic? I see it in the pics you posted
before, but then on the fixed jpegs I posted after that I don't see
it. I think it is because now the gray turned into white. In cany
case the gray should be a combination of underexposure and color
curves.

This one has the background slightly darker than the previous jpeg
I posted. It looks better because I coverted it from RAW.



I got rid of the color cast I think. But still, I think your main
problem is on getting correct exposures right off the bat.

This is the previous one.



And just for comparison's sake, this is yours. Hope you don't mind
me linking from your site, I don't have it anymore. Also, you might
need to do a sensor clean, I think I see a dust spot.

Click to expand...
--
Just hit that little white ball and search hard for it.
 
fasttempo123 said:
OK, I think I just can't get myself expressed well enough. Here is
another image I shot earlier with the level of details that I want
for my shots. This one is obviously a much easier object to shoot.
Click to expand...
Let me ask you a couple of very specific questions.

Do you still see the gray cast on the pink rope? If not, then what's the problem with my RAW conversion? The background is still too white? no shadows?

I can see the pic you posted last is correctly exposed from the beginning, you should be able to do the same with this frog one. But you'd have to shoot it again. Do it if you can in the same conditions as the one you took.
 
fasttempo123 said:
I am sending you the frog raw file where you can see the dark grey
cast on the pink string. That is what I am talking about and trying
to get rid off.
As the result the overall image looks dirty and lifeless. I
certainly appreciate your effort and help but I just can't get it
right with exposing to right. I have tried it as I stated in my
first message. If you look at the raw files the exposures are to
the right and they all have +2/3 compensation in it. I can shoot it
over easily but that is not what I want.
Click to expand...
It is an exposure issue. As already pointed out your camera meter is calibrated to a mid tone. The camera has no way of telling if the subject is black, grey or white so it always assumes it's a mid tone. A +2/3 exposure comp is not enough to make a white subject white, there are over +3 stops from mid grey to pure white [ on my 20D, it's likely the 30D will be similar]. It's a general problem with all reflected light metering, anything predominantly dark or light will result in exposure errors. Either use a grey card to get the reading, use the spot meter to meter a mid tone or use an incident light reading if you have a hand held meter.
 
You must log in or register to reply here.

Keyboard shortcuts

f
Forum
m
My threads
Mobile site
About
Editorial content
Cameras & Lenses
Community
All content, design, and layout are Copyright © 1998–2025 Digital Photography Review All Rights Reserved.
Reproduction in whole or part in any form or medium without specific written permission is prohibited.
When you use DPReview links to buy products, the site may earn a commission.
©GPS Media - Guides, Products, Services.
Back
Top