lsupremo wrote:
Using my Nikon D7100 and a 13mm 2.8 lens on a tripod taking indoor panorama images, how can I keep the white balance the same as I move from exposure to exposure around the room that may have exposure or color reflection differences?
I realize I should post this on the architectural forum, but I assume most of them also read this forum, and a lot of non Architectural readers can give me advise.
You can't, unless you balance the color temperature of the light sources, and use a custom, or manual, or preset white balance referenced to a target.
My strategies:
Worst case scenario, if there is a principal subject, I put a custom white balance target where that subject is, and do a custom/manual/preset white balance of the light falling there. The rest of the scene falls where it may.
If I can, I change light bulbs in lamps and fixtures to daylight LEDs, to match light from windows a bit better. Then I do a custom white balance from a target exposed to the mix.
If the predominant light source is cool white fluorescent, as it often is in a school or office, I put a .30 CC GREEN filter over my flash, and bounce flash off a white ceiling. Then I do a custom white balance from a target exposed to the mix.
If the predominant light source is incandescent (or "2700K" LED or CFL), I will put an 85 filter over my flash and bounce it off the ceiling for fill. Then I do a custom white balance from a target exposed to the mix.
If I'm photographing a theatrical production on dress rehearsal night, I'll ask the lighting director what sort of lights are in use. If all quartz-halogen, they're 3200K, so I'll dial that in. The result is that all the gels used will be reproduced at, or near, their lighting-designer-intended color. If they're LED, I'll ask the LD to give me a typical white sample. Then I do a custom white balance from a target exposed to that. Alternatively, I dial in 4800K.
There must be more than 50 custom white balance targets or tools available. Go to B&H's or Adorama's web site and check them out.
The most accurate white balance is achieved from an X-Rite ColorChecker Passport. But you can't always use one. That's why there are so many choices available.
Most targets work in both JPEG and raw capture post-production workflows. Passport is best used with raw workflow only.
Panoramas stitched from multiple captures should be exposed at the same full manual settings, to minimize transitional color/brightness jumps from frame to frame.
Remember that the human eye and brain are the best "auto exposure/auto white balance" system available. Camera sensors don't always interpret color and exposure very well. So you may have to live with a compromise.