Hi Guys: Thanks for all the input, but let me explain....
I usually shoot two rigs at a time in the bush...One A9 / SONY 100mm - 400mm GM +1.4xTC ; another A9 / 400mm f2.8 GM +2xTC because we have a very dusty environment and it is convenient to have a choice of focal reach at short notice. I never change lenses in the field.
I need to add that I only shoot in MANUAL mode; RAW (Compressed); AWB; AUTO ISO - Capped at ISO 1,600; Usually fully open, unless I am fairly close to the subject, so I stop down 2/3rd's to get decent over-all sharpness.
In 2018 I discovered this +3EV compensation by mistake, when I was squeezed for light early one morning. The EVF / Live View / Live histogram is really great to see what you are actually shooting, and will be what result you will get......
In desperation, to get a higher shutter speed, I tried adding light to the live view by turning the EV compensation dial... As I would it up, so the image in the live view got lighter. To get decent exposure I simply increased the shutter speed until the histogram moved back into the middle of it's frame...
I use the histogram all the time, and have set the viewfinder / rear screen to show the live histogram, so I can change shutter speed while looking through the viewfinder and on the fly.....
I absolutely don't profess to be a photographically, technically adept, "rocket scientist", but all I can say that, like a few of you readers have suggested, it seemed to fly in the face of all conventional photographic wisdom..... But in simple terms, it worked for me! Who am I to argue with that?
In the bush, we don't always have the time to think, and have to shoot "from the hip" as it were..... Every now and again, I check my histogram by pointing the camera at the surrounding area, maybe adjust the shutter speed to get the histogram right, so if I do see action, its a case of picking up the camera , pointing it at the subject, pushing my thumb down on the AF - ON button and holding it there, while I shoot in short bursts, even though I can shoot 20 frames per second... Invariably I end up with 30 - 40 frames in a sequence, so I can choose the best at my leisure.
I shot Canon 1DX MKii / 5D MKiv / 7D MKii until 2017 when I switched to mirrorless..... The SONY FF Mirrorless Alpha bodies certainly are different from anything in the DSLR world. The advantages ( For me..) far outweigh what I had with DSLR. When people start using the EVF / Live View / Live Histogram only then, will they understand how different and special, this new technology really is for photographers who shoot action sports and wildlife.
I am always happy to answer any questions about wildlife photography in the Africa bush, and if Luminous Landscape would find value in an article about the appropriate equipment, planning trips, where to go, seasonality etc, I am sure that Josh will let me know...