I don't have an A7r. On my A77 and A99 there is a menu choice: Live View Display Setting Effect On/Off. Setting effect Off is what I use with electronic flash.
I'm sure there's an easy answer to this, and I'm sure I'll feel really dumb when it's pointed out to me, but how do you frame and focus the a7R when you're using studio flash?
I set up to make some tests of corner smearing and color shift for my ongoing a7R testing, set the shutter speed to 1/125, the f-stop to f/16, looked through the finder, and couldn't see a darned thing! I had to open up the lens, change the shutter speed to a much lower setting so that the modeling lights provided enough illumination for the EVF image, frame and focus, then stop down and change the shutter speed back to 1/125 for the shot.
This was hugely cumbersome, and wouldn't work with a moving subject. What's the right technique?