Pro Photo HOME
Go Back   Pro Photo HOME > COLORRIGHT White Balance Tool - Full Access for Basic Members > COLORRIGHT Sales and Support

Notices

Reply
 
LinkBack Thread Tools Display Modes
  #1  
Old 05-13-2008, 02:40 AM
drew
Guest
 
Posts: n/a
COLORRIGHT works better with flash than competition

Here is another example of the advantages of the greater light transmission of COLORRIGHT.

Use with Flash Photography:

The ColorRight works better with flash than most other white balance cap products.

When using a flash with the expodisc you are not getting much of the flash light into the reading. This is because the expodisc is specifically designed to only allow 18% of the light to pass through the disc. The ColorRight allows 60% (3 times more light) to pass through to the sensors.

So what? You might ask.

Well, for one it works better in low light, especially on Nikon cameras in the instant preset wb setting mode.

But, even more importantly, it can lead to large differences when used with a flash. The meter reading doesn't really know how to account for the amount of flash that will be added back into the shot. Are you bouncing the flash? How high is the ceiling? How far away is the subject, really?

Here is a quick example of the difference.





I have also uploaded the raw files here for download. Please feel free to pull them down and balance around on the included whibal target in your favorite raw editor.

ColorRight Raw File:
http://www.colorright.com/colorrightflash.CR2

Other White Balance Cap: (expo)
http://www.colorright.com/expflash.CR2

As you can see the expo reading is far from accurate. You can improve the results of the expodisc a bit with flash by shooting in manual and taking your exposure reading and manually overexposing by about 2 to 3 stops.

How inconvenient is that?

  


White Balance so easy, even our 5 year old can do it.- Melissa Strickland

Digg this Post!Add Post to del.icio.usBookmark Post in TechnoratiFurl this Post!
Reply With Quote
  #2  
Old 05-13-2008, 09:26 AM
MikeA MikeA is offline
Premium Lifetime Member
 
Join Date: Jul 2003
Location: South Australia
Posts: 417
MikeA 10
Re: COLORRIGHT works better with flash than competition

I really like how the ColorRight makes the model smile more. Am I mistaken, or does he look thinner in the second photo? I think you're really onto something here Drew.

Mike.
__________________
Mike Adelaide

White Balance so easy, even our 5 year old can do it.- Melissa Strickland

Digg this Post!Add Post to del.icio.usBookmark Post in TechnoratiFurl this Post!
Reply With Quote
  #3  
Old 05-13-2008, 10:42 AM
Noel_Carboni's Avatar
Noel_Carboni Noel_Carboni is offline
Premium Lifetime Member
 
Join Date: Feb 2001
Location: Florida, USA
Posts: 5,326
Noel_Carboni
Re: COLORRIGHT works better with flash than competition

Nice demo images, Drew. The only thing I might suggest is to brighten the exposure levels so that the images aren't so dark.

-Noel
__________________
My eMail address: NCarboni@att.net

White Balance so easy, even our 5 year old can do it.- Melissa Strickland

Digg this Post!Add Post to del.icio.usBookmark Post in TechnoratiFurl this Post!
Reply With Quote
  #4  
Old 05-13-2008, 01:12 PM
Doug_Kerr's Avatar
Doug_Kerr Doug_Kerr is offline
Premium Lifetime Member
 
Join Date: Oct 2003
Location: Weatherford, Texas
Posts: 2,145
Doug_Kerr
Re: COLORRIGHT works better with flash than competition

Hi, Drew,

Quote:
Originally Posted by drew View Post
Here is another example of the advantages of the greater light transmission of COLORRIGHT.
Interesting examples.

I note that with a neutral background conveniently in place, "from the camera position" WB measurement can be expected to do a good job if we have a relatively-narrow acceptance pattern (as with the ColorRight diffuser). This is in fact a situation (we can call it the "giant gray card" approach) in which there is an explainable advantage to such a narrow pattern.

Certainly next time I have a subject in front of a neutral background, I will keep that in mind and put my trusty Color Parrot 1.2 into use (assuming I feel impelled to use a diffuser at all).

However, actually, in that setting, we should expect to get a fairly good WB measurement with just the naked lens, zoomed to include as much of the background as possible and as little stuff outside it as possible (and maybe put as out-of-focus as possible).

I don't suppose you made a comparison measurement with that technique, did you?

In any case, a "cosine" diffuser (such as the ExpoDisc diffuser), intended for use "at the subject", can't be expected to give a good WB measurement "at the camera position", even in this setting. That's why they are not recommended for such.

Quote:
But, even more importantly, it can lead to large differences when used with a flash. The meter reading doesn't really know how to account for the amount of flash that will be added back into the shot. Are you bouncing the flash? How high is the ceiling? How far away is the subject, really?
I'm having trouble quite following that story, and why it is that a greater through transmission is helpful in this regard. Note that the meter (both for flash and ambient components) reads through the lens (and diffuser, if in place), and so the photometric exposure for metered operation will not be affected by through transmission (any more than it would by difference in the f/ number).

And the relative contributions of reflected incident light and reflected flash light (in the light whose chromaticity is measured by the camera) will not be changed by differences through transmission.

Of course, as you pointed out earlier, the difference in through transmission can effect whether the camera (Nikon) is willing to use the "exposure" for chromaticity measurement at all or not. I assume that in your examples here, the camera didn't complain in either case.

The bottom line is that, in my opinion, this demonstration did not in any way illustrate an advantage of greater transmission, but rather showed that we can make a meaningful WB measurement "from the camera position" if we have a neutral background, but only if we use a diffuser with a narrow acceptance pattern (or, perhaps, no diffuser at all).
__________________
Best regards,

Doug

Visit The Pumpkin, a library of my technical writings:
http://doug.kerr.home.att.net/pumpkin

"Make everything as simple as possible, but no simpler."

White Balance so easy, even our 5 year old can do it.- Melissa Strickland

Digg this Post!Add Post to del.icio.usBookmark Post in TechnoratiFurl this Post!
Reply With Quote
  #5  
Old 05-13-2008, 01:30 PM
Doug_Kerr's Avatar
Doug_Kerr Doug_Kerr is offline
Premium Lifetime Member
 
Join Date: Oct 2003
Location: Weatherford, Texas
Posts: 2,145
Doug_Kerr
Color correction

Hi, Drew,

For what it's worth, the chromaticity of the WhiBal card in your test shot (as published) using the ColorRight was within 0.0024 u'v' units, pretty close to ideal color correction (assuming the WhiBal card to be "perfect").

Of course, we've heard from you that the WhiBal card can't really be reliably considered very neutral, owing to the possibility of faked data from the manufacturer (or maybe that's only for the pedigreed one I have - I don't quite remember), so perhaps the correction isn't really that good.

Best regards,

Doug

White Balance so easy, even our 5 year old can do it.- Melissa Strickland

Digg this Post!Add Post to del.icio.usBookmark Post in TechnoratiFurl this Post!
Reply With Quote
  #6  
Old 05-13-2008, 02:30 PM
Doug_Kerr's Avatar
Doug_Kerr Doug_Kerr is offline
Premium Lifetime Member
 
Join Date: Oct 2003
Location: Weatherford, Texas
Posts: 2,145
Doug_Kerr
Oops

Hi, Drew

In my recent post, I said:

Quote:
However, actually, in that setting, we should expect to get a fairly good WB measurement with just the naked lens, zoomed to include as much of the background as possible and as little stuff outside it as possible (and maybe put as out-of-focus as possible).
That was not fully accurate. It may apply as stated to the Nikon WB measurement system - I am not familiar enough with the details of its working to be sure.

In the Canon context, a more accurate statement would have been:

However, actually, in that setting, we should expect to get a fairly good WB measurement with just the naked lens, aimed so that only background fell within the "guide circle".

My apologies for the incomplete statement.

Best regards,

Doug

White Balance so easy, even our 5 year old can do it.- Melissa Strickland

Digg this Post!Add Post to del.icio.usBookmark Post in TechnoratiFurl this Post!
Reply With Quote
  #7  
Old 05-13-2008, 06:10 PM
drew
Guest
 
Posts: n/a
Re: Color correction

Quote:
so perhaps the correction isn't really that good.

I put it in there for you, Doug.

Because I knew you'd want a reference. This is one you like, no?

There are issues with its use for stringent measurement. Depending on where I click on the whibal I can get a pretty good variety of readings.

But, why bother going down that rabbit trail again.

White Balance so easy, even our 5 year old can do it.- Melissa Strickland

Digg this Post!Add Post to del.icio.usBookmark Post in TechnoratiFurl this Post!
Reply With Quote
Reply

Thread Tools
Display Modes

Posting Rules
You may not post new threads
You may not post replies
You may not post attachments
You may not edit your posts

BB code is On
Smilies are On
[IMG] code is On
HTML code is Off
Trackbacks are On
Pingbacks are On
Refbacks are On




All times are GMT -4. The time now is 09:09 PM.


ColorRight





Professional Photo Resources Atlanta

Photo Barn


Geo Visitors Map

Content Relevant URLs by vBSEO 3.1.0