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ExpoDisc Conversation with Diane Wallace
- Thread starter pbleic
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Jim Coffey #162382
Well-known member
As a plastics guy we tend to design our neutral color LDPE plastic to be a bit on the blue side. Yellow looks dirty to the consumer.
Don't be surprised if all pringle's lids are slightly blue - but they're pretty darn close to neutral and a whole lot cheaper than an expodisk. Which is why I have a pringle's lid in my camera bag.
Don't be surprised if all pringle's lids are slightly blue - but they're pretty darn close to neutral and a whole lot cheaper than an expodisk. Which is why I have a pringle's lid in my camera bag.
Doug Walker
Senior Member
See this test, Expodisc vs. Pringles:
http://forums.dpreview.com/forums/read.asp?forum=1019&message=6652594
Of course, you can always readjust WB in Photoshop if you know what you're doing and have the right tools.
--
Doug Walker
Check my profile for equipment list.
http://forums.dpreview.com/forums/read.asp?forum=1019&message=6652594
Of course, you can always readjust WB in Photoshop if you know what you're doing and have the right tools.
--
Doug Walker
Check my profile for equipment list.
Read the ExpoDisc literature - if you put a warming filter in when doing WB, you get cooling and vice versa. If it makes Blue WB, it is yellow tinged.
Paul
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Photographs at: http://www.pbase.com/pbleic
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Copyright 2003, 2004 All rights reserved.
--
Paul
------------------------------------------------
Pbase supporter
Photographs at: http://www.pbase.com/pbleic
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Copyright 2003, 2004 All rights reserved.
LeeBase
Veteran Member
I completely understand. It's certainly far better than what AWB gives you.
Lee
When shooting a sunlit subject at short distances from the lens (even a very varied, multi-color subject), CWB set using reflected light will often have a distinct color cast, whereas CWB set using incident light (i.e. aimed at the sun) will have "correct" WB. I have observed this many, many times- it is reproduceable.
Try shooting a closeup of some brightly colored flowers, using incident and reflected light, and let me know if you don't find a difference. The ExpoDisc can't work miracles.
As I've said elsewhere, the only time I find reflected light to sometimes produce distinctly better WB results is indoors under mixed lighting, when it would be difficult to figure out where exactly to aim for an incident light reading.
To get perfect WB under those conditions, you should aim your Expodisc at a gray card...hahahhahaha.
Try shooting a closeup of some brightly colored flowers, using incident and reflected light, and let me know if you don't find a difference. The ExpoDisc can't work miracles.
As I've said elsewhere, the only time I find reflected light to sometimes produce distinctly better WB results is indoors under mixed lighting, when it would be difficult to figure out where exactly to aim for an incident light reading.
To get perfect WB under those conditions, you should aim your Expodisc at a gray card...hahahhahaha.
It is very easy to demonstrate that the ExpoDisc cannot always produce perfect WB using reflected light. If we actually get some blue sky tomorrow, I'll do what I've done a dozen times before with the same results- I'll shoot a close-up of a standard test target, using incident and reflected light, and you'll see that incident light is better.
The fancy light-gathering prism in the ExpoDisc looks strikingly like the plastic flourescent light diffusers I see at Home Depot, so I'm not surprised that 25 cents of plastic doesn't work miracles. I bought the thing because I know it doesn't impart a color cast to the light passing through it, and the 18% reference is handy.
The fancy light-gathering prism in the ExpoDisc looks strikingly like the plastic flourescent light diffusers I see at Home Depot, so I'm not surprised that 25 cents of plastic doesn't work miracles. I bought the thing because I know it doesn't impart a color cast to the light passing through it, and the 18% reference is handy.
phototakeouter
Leading Member
Paul,
Yes I did re-read the exposure thread. All I can say is if that's what you took away from it, I'm happy for you. Of course your positions are always well-researched and backed by numerous supporting views. By all means, continue posting your invaluable threads. I will refrain from tainting them with my simple observations and comments. They will not be missed anyways.
Lee,
I'm not sure how old you are but the puerile game of put up or shut up should have been left behind sometime before you graduated high school. No one is obliged to show you their photos, especially not given your "show me you're right otherwise you're wrong" attitude.
regards.
Yes I did re-read the exposure thread. All I can say is if that's what you took away from it, I'm happy for you. Of course your positions are always well-researched and backed by numerous supporting views. By all means, continue posting your invaluable threads. I will refrain from tainting them with my simple observations and comments. They will not be missed anyways.
Lee,
I'm not sure how old you are but the puerile game of put up or shut up should have been left behind sometime before you graduated high school. No one is obliged to show you their photos, especially not given your "show me you're right otherwise you're wrong" attitude.
regards.
Actually, one thing I took out of it was this:
"I understand now, and agree with you. When it comes to exposure, it's much more important to get it balanced, and know how and why you did so, before you start deliberately going over or under.
I also agree about the point and shoot flash effect. Greater abilities should be worked to produce greater effects, not to produce the same thing with greater ease.
I think what confused several people was it seemed you were advocating one correct exposure. Thanks for clearing it up.
regards."
This was YOUR post at the time! LOL.
I will refrain from tainting them with my simple
Whatever works for you. I am delighted to have your posts in my forum. If you decide not to participate - so be it. But not because I don't welcome your remarks.
You and I disagree here and back then about one basic thing - you seem to give equal weight to your opinion and that of highly experienced professional photographer/writers. I tend to view their opinion as generally more valuable than mine in matters of photography. I have been humbled at times, feeling that I am right about something, only to learn that I was ignorant of the details because of my lack of experience. I have learned to listen to experience. Not without questions. Not to the exclusion of common sense.
--
Paul
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Pbase supporter
Photographs at: http://www.pbase.com/pbleic
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Copyright 2003, 2004 All rights reserved.
jasonh213584
Member
Hi Paul,
I too had this idea until I thought about it and tested it. Actually, it's the reverse of what you've stated. A warm up gel/filter + ExpoDisc will you a warmer reference and the subsequent shots will be artificially warmed up to compensate. This does seem counter-intuitive, doesn't it?
Let me explain with the Pringles lid example. In "perfect" WB conditions, say 128,128 and 128 RGB, take a reference shot with a Pringles lid. This reference shot will be, say, 128,128, 150 (i.e. a strong blue). ( )
If you then take a picture of a gray card, the hardware/software doing the compensation will adjust the values of the RGB channels to match those of your reference shot. So if the gray card channels were 128,128 and 128, the hw/sw will add more blue to compensate. The result will be a blue cast.
If you re-read the ExpoDisc literature, you will see this confirmed.
I too was confused by this, which made me sit down and think about it, take some pictures to check and then think about it some more.
Try it out for yourself.
Jason.
( ) - This is a rather extreme example for illustrative purposes only. The Pringles lid values are usually just a few out from a neutral equilibrium.
I too had this idea until I thought about it and tested it. Actually, it's the reverse of what you've stated. A warm up gel/filter + ExpoDisc will you a warmer reference and the subsequent shots will be artificially warmed up to compensate. This does seem counter-intuitive, doesn't it?
Let me explain with the Pringles lid example. In "perfect" WB conditions, say 128,128 and 128 RGB, take a reference shot with a Pringles lid. This reference shot will be, say, 128,128, 150 (i.e. a strong blue). ( )
If you then take a picture of a gray card, the hardware/software doing the compensation will adjust the values of the RGB channels to match those of your reference shot. So if the gray card channels were 128,128 and 128, the hw/sw will add more blue to compensate. The result will be a blue cast.
If you re-read the ExpoDisc literature, you will see this confirmed.
I too was confused by this, which made me sit down and think about it, take some pictures to check and then think about it some more.
Try it out for yourself.
Jason.
( ) - This is a rather extreme example for illustrative purposes only. The Pringles lid values are usually just a few out from a neutral equilibrium.
This is exactly the opposite of what the ExpoDisc site says.
Paul
------------------------------------------------
Pbase supporter
Photographs at: http://www.pbase.com/pbleic
--------------------------------------------------
Copyright 2003, 2004 All rights reserved.
--I too had this idea until I thought about it and tested it.
Actually, it's the reverse of what you've stated. A warm up
gel/filter + ExpoDisc will you a warmer reference and the
subsequent shots will be artificially warmed up to compensate.
This does seem counter-intuitive, doesn't it?
Let me explain with the Pringles lid example. In "perfect" WB
conditions, say 128,128 and 128 RGB, take a reference shot with a
Pringles lid. This reference shot will be, say, 128,128, 150 (i.e.
a strong blue). ( )
If you then take a picture of a gray card, the hardware/software
doing the compensation will adjust the values of the RGB channels
to match those of your reference shot. So if the gray card
channels were 128,128 and 128, the hw/sw will add more blue to
compensate. The result will be a blue cast.
If you re-read the ExpoDisc literature, you will see this confirmed.
I too was confused by this, which made me sit down and think about
it, take some pictures to check and then think about it some more.
Try it out for yourself.
Jason.
( ) - This is a rather extreme example for illustrative purposes
only. The Pringles lid values are usually just a few out from a
neutral equilibrium.
Paul
------------------------------------------------
Pbase supporter
Photographs at: http://www.pbase.com/pbleic
--------------------------------------------------
Copyright 2003, 2004 All rights reserved.
David Barker91965
Senior Member
The ExpoDisc web-site isn't as clearly written as it could be, but the filter they suggest inserting to nudge the CWB towards warming things up is a cool filter. The camera then warms the subsequent shots to compensate, and now that you don't have a cool filter in place any more the overall effect is a slightly warm color balance - which people seem to respond positively to, as with sunsets, candlelight etc.
--
DB
--
DB
They suggest sandwiching an 82b filter to get a warming effect:
http://www.expodisc.com/articlesandreviews/daveharp.html
Here is an 82b filter:
Decidedly blue, not yellow.
Here is what Diane Wallace said here on the Nikon D1 Users Group:
If you don't like a pure white WB, you can warm it up by sandwiching an ExpoDisc with an 82B filter while setting custom WB, then shoot without that filter when you are photographing. That will trick the software to overcompensate in its filtration, and result in a warm WB at capture. A great trick on overcast days.
http://www.nikond1.net/ubb/Forum4/HTML/000098.html
Paul
------------------------------------------------
Pbase supporter
Photographs at: http://www.pbase.com/pbleic
--------------------------------------------------
Copyright 2003, 2004 All rights reserved.
http://www.expodisc.com/articlesandreviews/daveharp.html
Here is an 82b filter:
Decidedly blue, not yellow.
Here is what Diane Wallace said here on the Nikon D1 Users Group:
If you don't like a pure white WB, you can warm it up by sandwiching an ExpoDisc with an 82B filter while setting custom WB, then shoot without that filter when you are photographing. That will trick the software to overcompensate in its filtration, and result in a warm WB at capture. A great trick on overcast days.
http://www.nikond1.net/ubb/Forum4/HTML/000098.html
--I too had this idea until I thought about it and tested it.
Actually, it's the reverse of what you've stated. A warm up
gel/filter + ExpoDisc will you a warmer reference and the
subsequent shots will be artificially warmed up to compensate.
This does seem counter-intuitive, doesn't it?
Let me explain with the Pringles lid example. In "perfect" WB
conditions, say 128,128 and 128 RGB, take a reference shot with a
Pringles lid. This reference shot will be, say, 128,128, 150 (i.e.
a strong blue). ( )
If you then take a picture of a gray card, the hardware/software
doing the compensation will adjust the values of the RGB channels
to match those of your reference shot. So if the gray card
channels were 128,128 and 128, the hw/sw will add more blue to
compensate. The result will be a blue cast.
If you re-read the ExpoDisc literature, you will see this confirmed.
I too was confused by this, which made me sit down and think about
it, take some pictures to check and then think about it some more.
Try it out for yourself.
Jason.
( ) - This is a rather extreme example for illustrative purposes
only. The Pringles lid values are usually just a few out from a
neutral equilibrium.
Paul
------------------------------------------------
Pbase supporter
Photographs at: http://www.pbase.com/pbleic
--------------------------------------------------
Copyright 2003, 2004 All rights reserved.
No, that isn't what happens.
When it sees 128, 128, 128 it will balance by SUBTRACTING blue to introduce a yellow cast.
--
Paul
------------------------------------------------
Pbase supporter
Photographs at: http://www.pbase.com/pbleic
--------------------------------------------------
Copyright 2003, 2004 All rights reserved.
Once it sees grey as "blue" it will automatically subtract blue from everything.
When it sees 128, 128, 128 it will balance by SUBTRACTING blue to introduce a yellow cast.
--
Paul
------------------------------------------------
Pbase supporter
Photographs at: http://www.pbase.com/pbleic
--------------------------------------------------
Copyright 2003, 2004 All rights reserved.
jasonh213584
Member
Doh!
I knew I should have had another coffee before posting. You are of course, quite correct.
I hang my head in shame and will go to make another coffee. Clearly the first one didn't work properly.
Sorry for the confusion.
How embarrassing.
Jason.
I knew I should have had another coffee before posting. You are of course, quite correct.
I hang my head in shame and will go to make another coffee. Clearly the first one didn't work properly.
Sorry for the confusion.
How embarrassing.
Jason.
David Barker91965
Senior Member
--
DB
--
Paul
------------------------------------------------
Pbase supporter
Photographs at: http://www.pbase.com/pbleic
--------------------------------------------------
Copyright 2003, 2004 All rights reserved.
LeeBase
Veteran Member
LeeBase
Veteran Member
1. ExpoDisc seems to be the best way to hit WB right when compared with other "lens covering" methods.
2. Sometimes perfect WB is not ideal for people to look at - a bit too cool. Can be warmed by sandwiching a cooling filter at the time of the ExpoDisc exposure.
3. Pringles and coffee filters, etc. can get close (to varying degrees), but not right on.
4. Cost/benefit ratio is definitely a strong consideration for many - the ExpoDisc is expensive.
5. With a single light source, incident light method is best (point it at the light source).
6. Reflective light method usually works well (point at the scene), but can be wrong if there is a dominant scene color and it is "all around"
7. White and grey cards can also work, but have limitations as well (can be damaged carrying them around, must be placed in the scene - difficult for landscapes, though there are workarounds, glare, different quality manufacture)
8. Everyone needs to balance what factors are important to them in their own photography.
--
Paul
------------------------------------------------
Pbase supporter
Photographs at: http://www.pbase.com/pbleic
--------------------------------------------------
Copyright 2003, 2004 All rights reserved.
2. Sometimes perfect WB is not ideal for people to look at - a bit too cool. Can be warmed by sandwiching a cooling filter at the time of the ExpoDisc exposure.
3. Pringles and coffee filters, etc. can get close (to varying degrees), but not right on.
4. Cost/benefit ratio is definitely a strong consideration for many - the ExpoDisc is expensive.
5. With a single light source, incident light method is best (point it at the light source).
6. Reflective light method usually works well (point at the scene), but can be wrong if there is a dominant scene color and it is "all around"
7. White and grey cards can also work, but have limitations as well (can be damaged carrying them around, must be placed in the scene - difficult for landscapes, though there are workarounds, glare, different quality manufacture)
8. Everyone needs to balance what factors are important to them in their own photography.
--
Paul
------------------------------------------------
Pbase supporter
Photographs at: http://www.pbase.com/pbleic
--------------------------------------------------
Copyright 2003, 2004 All rights reserved.
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