Quote Originally Posted by Sheiky


At the wedding of my sister I also took some shots inside, but the flash output color didn't match the ambient lighting. So I'm looking for a solution for the next wedding. Of course I will try the high-ISO capabilities of my 5D2, but I'm wondering how you determine the right flash output etc.


How can I compensate best for ambient light? How do you determine what the right white balance is?


I use my camera as a simplistic (though slow) color temperature meter. I shoot a gray card (actually it's a Photovision white/gray/black card) in ambient light with the camera in Kelvin WB at 5200 and view the results with the RGB histogram. If the red channel is brighter than the blue, I lower the temp; if the red channel is darker than the blue, I raise the temp. I reshoot and recheck until the red and blue are over each other, then use the WB shift menu to adjust the green channel to align with the red/blue channels. Once I know the temp/shift of ambient, I then choose what level of CTO/CTB and +green/-green are needed to get the flash to match ambient. This has been my "money-maker" for accurate, consistent color.


As an alternative, you could go to the site during the relative times you'd be shooting and capture reference shots of your gray card. Take them home, load them into Lightroom or similar, and read the color temperature off the gray card. I've had to do this with cave photography, where the ambient was below the settable K range of my camera.


With practice using one of these methods, you'll learn how to guess and be close most of the time.