If you are shooting in a different aspect ratio than the expected final output, place an Aspect Guide on your page for framing your shots instead of just using gaffer tape. These act like a Matte, but do not affect your footage.
Aspect - Settings
ON
Enable/Disable the Aspect guide. You can also enable or disable the tool by selecting it on the tool bar. It will be Green when enabled and Grey when disabled.
RATIO
Select the aspect ratio you wish to visualize with the guide. There are several presets that you can use. If none of these meet your needs, you can create your own with the Custom setting if using a non-standard ratio.
Custom Ratio (x.xx : 1) will open two new menu options:
WIDTH - This sill translate as a % from left to right.
HEIGHT - This will translate as a % from top to bottom of the frame.
STYLE
You have two options.
MATTE - will give you "bars" over the top of the image.
LINE - Will have a 2-3 Pixel line, like a guide line, showing you the edges of the aspect you have selected.
*Line style may be more helpful when needing to see very clearly what is outside the active area as it will not get ‘painted’ over as it does with solid color.
Color
Define the color of the overlay area if using ‘MATTE’ style or define the color of the border when using ‘LINE’ style.
Opacity
Adjusts the opacity/transparency of the matte area or line borders depending on the chosen Style.
Aspect - Quick Start
For this example we will be preparing for a cinemascope (2.39:1) aspect ratio while filming in standard 16x9. This means we wish to visualize the top and bottom of the image being cropped for the final product via Aspect Guides.
From any page, click the joystick or tap the screen on a touchscreen monitor and select ‘Add New Tool’
Navigate to Frame > Aspect and select the '+' to add it to the current page.
Once added you can edit the settings by navigating right or tapping the right arrow when ‘Aspect’ is highlighted.
The default setting is for previewing a 4:3 aspect ratio for older TVs. Select 'Ratio' and change it to 2:39 to see the black bars switch to a horizontal configuration.
By default the bars are set to 50% opacity; adjust 'style' and 'opacity' to taste for whatever you find most viewable. Here I set the opacity to 80% to keep the off-screen areas from being distracting.
If your production relies on boom audio, you can use the top and bottom dead zones to give your boom operator a 'grace area' for getting close-but-not-too-close.