The Live View Controls tool offers a number of options to manage the Live View image. In addition, the DOF/EPV button can be used to check exposure and, in some cases, check the depth of field and even confirm focus accuracy at the taking aperture.
Orientation. Click on the Orientation fly-out menu and select between default, 0, 90, 180, and 270 degrees to rotate the Live View image accordingly. For example, if the camera is on its side for a vertical capture, you can set the Live View image in the Viewer to display the image in the same vertical orientation.
Lightness. Adjust the lightness slider if the Live View image seems too dark or too bright for the ambient lighting conditions. If grayed out, then this option is not supported when using the attached camera.
Quality. It adjusts the Live View image quality. Higher quality levels will produce a slower frame-rate. If the image quality remains low, the issue may be due to computer resources; either reduce the size of the viewer or reduce zooming levels. If grayed out, then this option is not supported when using the attached camera.
Start/Pause Live View. Press this button to resume or pause the Live View image stream at any time. The Live View image stream is typically initiated upon the opening of the Live View window. The stream is paused for 30 seconds by default. Note that the image stream duration can be extended up to 20 minutes in the preferences. In the main menu, go to Capture One/Edit -> Preferences. Go to the Capture tab and select a necessary option from the fly-out menu in the Live Preview field.
DOF (Canon)/EPV (Nikon). Depending on the model and exposure settings, selecting this will stop the lens down to the taking aperture and display the expected exposure result with the current settings.