I have been fiddling with many different Canon, Sigma, and Sony lenses and have come finally come peace with one favorite lens and setup for my new Sony A7Rii. While many Canon lenses offered IS, those lenses didn’t have a wide aperture which caused problems in low-light. My current fastest lens is the Sigma 24mm F1.4 (for Canon) and I really love using it along with Sigma MC-11 adapter on my Sony A7Rii, particularly because I can get a very wide-angle at full-frame mode and also get something like a 35mm in Super 35mm mode.
Also, Sigma lenses actually do quite well in video auto-focus mode (with both MC-11 and Speedbooster) while most Canon-branded lenses simply fail to focus at all. Now, the Sigma 24mm F1.4 does make quite a bit of sound while doing auto-focus but this can be fixed with a separate audio source or use a wireless microphone (that is what I am doing).
The Sony A7Rii doesn’t give you full 5-axis stabilization with this setup but it does give you the in-camera stabilization, which isn’t the best but I can always use a tripod or gimbal. I realize you do not want to sacrifice low-light performance for stabilization, although that’s what I wanted initially, if you want to get the best quality images out of the Sony A7Rii.
The video above was made in full-frame mode on the Sony A7Rii (I intentionally didn’t use Super 35mm but will have a test on that also) all hand-held. All stabilization was done in-camera and I did not do any kind of post-processing such as warp stabilization or color grading. I left everything out on purpose so you can see what this camera can do in low-light with the Sony A7Rii w/ a fast lens like Sigma 24mm F1.4. But I am very satisfied and this will be my main setup for travel.