White balance question

Gints Klimanis · March 21st, 2009, 01:46 AM

Quote:

Originally Posted by Serena Steuart

It isn't necessary to WB from a white card, cloth etc. But it is important that it be a neutral colour, meaning gray. A Kodak 18% gray card is ideal. If you use white, stop well down (a couple of stops) to get an accurate setting.

I decided to measure a few cards with my D3 under a Solux light. I took pictures of the cards (exposed such that they spike at 50% on the histogram) and took large area samples with Nikon Capture NX2. Only Red/Green and Blue/Yellow axis values are revealed. The importance of the values is how they compare. The WhiBal is the product to trust for spectral neutrality, and apparently, so is Kodak grey.

WhiBal: Red 0.85, Blue 1.22
Kodak Grey: Red 0.84, Blue 1.22
Kodak White: Red 0.85, Blue 1.13
Average Printer paper: Red 0.85, Blue 1.11
ExpoDisc: someday ...

This shows the printer paper and Kodak white (grey one side, white other side, about three years old) to be yellowish, which doesn't surprise me as paper yellows quickly from sun exposure and slower over time. Kodak Grey as it is manufactured as an exposure reference card, so I've read a number of comments questioning its spectral neutrality. This test shows me that my Kodak grey card at this point in time is nearly identical to the WhiBal.

Gints Klimanis · March 21st, 2009, 02:05 AM

Quote:

Originally Posted by Mitchell Lewis

I use 4100 for fluorescents.

There are a lot of types of fluorescent lights. Most of my warm bulbs register betwenn 2700 and 2800 K on my EX1. The bulbs at the martial arts place are 5500K. Office and lab bulbs run as high as 6500K. My fish tank lights are 10000K or 18000K, depending on the bulbs.

Razvan Amarandei · June 14th, 2009, 04:43 AM

hi!

I'm shooting most weddings and i've just purchase EX3, My old PD170 has a good auto WB. Whit my EX3 I'm not so happy about the AWB
now I don't know if it's only my camera but using EX3 on PP, AWT I still can Execute manual WB...If i pres the Full auto button still I can Execute WB... If I use the camera in full manual mode, I've seen that having a white subject (white shirt) in prim plan, the background is becoming darker. moving away from the white subject to the background the image it's dark and is becoming lighter. (full manual: iris, focus,)
that it's ok???
THX for your help.
razvan

Dylan Morgan · June 14th, 2009, 12:34 PM

The EX-1/3 have horrible ATW that's supposed to be better with the new firmware. If you have a PP that you prefer to use at a wedding, then you can place the WB switch to PRST and it will revert to the white setting that you have dialed in for that PP. You cannot execute a manual WB by pressing the button with PRST selected. You can adjust your color temp through the menu only. This shifts the oranges and blues which is for tunsten and natural light. If you feel that you want to do a manual WB by pressing the button then avoid the "B" switch which is ATW. If you leave it on "B" the camera will execute a CT number but soon after it will try and adjust mid-shooting (I believe). Just leave it on "A" and execute your WB with a card or if need be, a white subect. As for your subject having exposure problems, if you're not in auto iris then perhaps you are moving from one more lit area to a darker one. Different light sources at different angles can be interesting for exposure (as I'm sure you know) or maybe this could be a PP Gamma that can be crushing the blacks more than you prefer... If all else fails, just take your camera back to your dealer and show him what is happening and see if there's anything defective.
I've learned so much from these generous professionals on here good luck my friend.

Serena Steuart · June 15th, 2009, 02:48 AM

The white balance switch settings depend on your set up. The default PRST is 3200K but that can be set to a different temperature within PP (as said above). Positions A and B can be be preset to your chosen CT. You may choose to set one to AWB. Pressing the WB button (under the lens) will over write whatever was set on the selected A or B.

June 14th, 2009, 04:43 AM	#18
Razvan Amarandei Tourist Join Date: Mar 2008 Location: Bratislava, Slovakia Posts: 2	awt hi! I'm shooting most weddings and i've just purchase EX3, My old PD170 has a good auto WB. Whit my EX3 I'm not so happy about the AWB now I don't know if it's only my camera but using EX3 on PP, AWT I still can Execute manual WB...If i pres the Full auto button still I can Execute WB... If I use the camera in full manual mode, I've seen that having a white subject (white shirt) in prim plan, the background is becoming darker. moving away from the white subject to the background the image it's dark and is becoming lighter. (full manual: iris, focus,) that it's ok??? THX for your help. razvan

June 14th, 2009, 12:34 PM	#19
Dylan Morgan Regular Crew Join Date: Feb 2009 Location: Portland OR Posts: 70	The EX-1/3 have horrible ATW that's supposed to be better with the new firmware. If you have a PP that you prefer to use at a wedding, then you can place the WB switch to PRST and it will revert to the white setting that you have dialed in for that PP. You cannot execute a manual WB by pressing the button with PRST selected. You can adjust your color temp through the menu only. This shifts the oranges and blues which is for tunsten and natural light. If you feel that you want to do a manual WB by pressing the button then avoid the "B" switch which is ATW. If you leave it on "B" the camera will execute a CT number but soon after it will try and adjust mid-shooting (I believe). Just leave it on "A" and execute your WB with a card or if need be, a white subect. As for your subject having exposure problems, if you're not in auto iris then perhaps you are moving from one more lit area to a darker one. Different light sources at different angles can be interesting for exposure (as I'm sure you know) or maybe this could be a PP Gamma that can be crushing the blacks more than you prefer... If all else fails, just take your camera back to your dealer and show him what is happening and see if there's anything defective. I've learned so much from these generous professionals on here good luck my friend.

June 15th, 2009, 02:48 AM	#20
Serena Steuart Major Player Join Date: Jun 2006 Location: Studio Alnitak, Melbourne, Victoria, Australia Posts: 640 Images: 3	The white balance switch settings depend on your set up. The default PRST is 3200K but that can be set to a different temperature within PP (as said above). Positions A and B can be be preset to your chosen CT. You may choose to set one to AWB. Pressing the WB button (under the lens) will over write whatever was set on the selected A or B.