The Canon EF 24-105 f/4L IS USM is one of the most commonly used lenses with the Sony FS7 or FS5. In combination with the Metabones E-Mount T Speed Booster Ultra 0.71 it turns into a very versatile tool for documentary shooters.
Unfortunately the lens is not parfocal, as this short test video shows. It also suffers from focus breathing, especially at shorter focal lengths. The image stabilization however works very well and I find it indispensable when working handheld with a small and bare-bones FS5.