If your camera's focus seems to be "popping", or going in-and-out, or jumping...it is likely that Auto-Focus is turned on for Switcher Studio. As your subject moves, Auto-Focus will continuously try readjusting itself.
To check for Auto-Focus, check the top-middle of the app for the letters "AF", which stands for "Auto-Focus".
If the icon is highlighted, then Auto-Focus is enabled. Tap the icon to turn Auto-Focus off. To manually focus the picture, cue a source in the Preview pane, and then tap the part of the image you want to emphasize.
You can also open the "Camera Control" menu and toggle ON the "Disable Auto Focus When Live" setting. This will negate the AF setting for the angle that is shown in the Preview window while the source is Live. Using this, you could have an Angle on Auto-Focus while it is cued up, but switch to Manual Focus automatically when the source goes Live.