Use your eyepiece, and make sure that it is set to monochrome (black and white) and high detail. You'll be able to see things like the grain of the focusing screen like that. And I wouldn't turn the Letus motor on while you do that.
Also, it's not wise to mess with in-camera settings in the middle of a shoot. As you now know, by doing that you'll end up with two halves of a whole that must then be color-corrected to fix the color shift. Scene file settings are fun, and I have a few customs that I use, but for now you may be better off shooting flat, concentrating on white balance/focus/exposure, and tweaking your look in post.
Also, it's not wise to mess with in-camera settings in the middle of a shoot. As you now know, by doing that you'll end up with two halves of a whole that must then be color-corrected to fix the color shift. Scene file settings are fun, and I have a few customs that I use, but for now you may be better off shooting flat, concentrating on white balance/focus/exposure, and tweaking your look in post.