I've just returned from 17 days of field testing in some great locations with the Canon EOS R5 (best camera ever), Canon RF 100-500mm F4.5-7.1 L IS USM Lens (awesome lens), and an assortment of other gear.
A solid set of images of this huge Alaska Yukon moose was the reward for packing gear nearly three miles into the Alaska mountains. On this afternoon, the cloudy sky created soft, shoot-from-any-direction lighting, and the light rain saturated the fall-colored foliage and hemlock backdrop. I couldn't have scripted a scenario much better than this.
Working in the thick forest meant a zoom focal length was required clear obstructions while facilitating ideal framing that included, at times, a significant amount of the environment around the subject(s). The need to move and work fast meant there was no time for tripod setup. While the RF 100-500 does not have the widest aperture, its image stabilization system coordinating with the R5's in-body image stabilization meant that nearly all of my images were sharp. I came away very impressed and have been re-training my brain to shoot handheld at longer shutter speeds throughout the trip. That is when the animal was motionless.
When photographing wildlife, I usually use manual exposure mode with the aperture wide open (unless the scenario dictates otherwise) along with auto ISO. These settings enable the top dial to be quickly rolled to the minimum shutter speed required to stop any camera or subject motion (or until ISO 100 is reached) in the current shooting scenario. Often, after getting the insurance shots with a relatively fast shutter speed, I capture images at progressively longer exposures attempting to better what has already been captured. Exposure compensation was adjusted as appropriate as moose are very dark animals, encouraging the camera to overexpose the scene.
For this shoot (and for most wildlife photography), AI Servo AF was used, readying the camera for any movement the animal makes. For the moose photos, touch and drag AF was used with the small AF point selected. While this camera's animal eye AF is awesome (game-changing for most wildlife photography, including birds), the black around the moose's eye caused animal eye AF challenge enough times that I opted for the also-good alternative selection method. When I did my job correctly, nearly all images were focused correctly.