Shooting images for a spherical panorama (virtual reality - VR) involves directing the camera in every direction, including away from and into the Sun, vertically upwards and probably vertically downwards. Each of these directions involves a different direction of light and different overall illumination. Individual images must consequently be processed to a significant extend to achieve seamless integration of the panorama.
RAW mode offers the largest margin for adjustment of exposure, white balance, recovery of detail in highlights etc, and it therefore the preferred mode for creating the original images. When shooting panoramas it is usually worth using exposure compensation to capture each image one or two stops either side of the standard exposure settings. It is therefore worth noting that three RAW mode files generally cover an exposure range equivalent of that achieved bu 5 or 6 JPEG files. RAW mode produces larger files than the JPEG mode but also has the advantage of eliminating artifacts arising from compression algorithms. However, RAW files have proprietary formats (ie the format is different for each camera manufacturer) and must consequently be processed and exported as TIFF or JPEG files prior to importing them in to a panoramic stitching program.
RAW files produce slightly softer images than formats such as TIFF because it is intended that RAW images should be sharpened as part of the processing operation. No de-mosaicing or in-camera sharpening takes place, and should therefore be performed post capture.