I am extremely pleased when shooting stills in RAW and white-balancing the pictures afterwards. For this purpose a rough white balance for the live view preview is sufficient.
However, I am not so pleased about setting the white-balance for video shooting purposes on the Canon 5DIII. Apart from the possibility of using Magic Lantern and shooting RAW video, you need to tune the WB before shooting video. For wide angle scenery shots I prefer to shoot in ambient light only (except in darkness) instead of using artificial light. For example, at 25-30 meter blue water depth, it is possible to achieve good WB with stills (which proves that the camera sensor is capable of this), but I have been having difficulty in achieving similar quality in video.
I have tried the different WB modes as well as dialling in the Kelvins. I have also tried the custom white balance with a white bag or white-ish sand and further fine-tuning by the WB Shift underwater. It seems difficult to not lose the reds and yellows whilst keeping the water column blue. I am wondering if I am doing something wrong??
I also gave a try with the Canon picture style editor with the idea of creating personal presets for different depths. As reference pictures I used various (still) RAW pictures shot at 25-30 meters. Whilst these pictures were easy to WB adjust in the Canon Digital Photo Proferssional software, there was not sufficient latitude available in the picture style editor. I am now wondering whether there are similar limits for white-balancing video/the live view screen?
What have your experiences been in shooting video with ambient light only at different depths?
Or should I bite the bullet and go ML raw video with all the additional expenses?