Upload & Sell: On
...My main objective is ...white balance. I have noticed that my ipad3 displays color different than my laptop.
Unless your displays are color calibrated regularly that is a problem. Not all devices can be calibrated. The best bet is to take a shot, under the final lighting setup, of a standard color reference, and adjust color balance in post. That way, the colors in the final image will accurately reflect reality, which can be important in product, fashion, and architectural work. (Capture in raw mode, of course.)
I use the Datacolor SyderChekr, with the SpyderCube attached for black/white exposure control, and others I know who do work for Realtors use this or X-Rite's ColorChecker Passport. They make getting accurate, consistent color in all the images in a series -- even when shot under differing lighting conditions, using different cameras, and/or by different photographers -- fast and easy.