Location:
The Render Manager > Scene Render Options
Choose Render > Render > Scene Options from the Render toolbar.
Options: Scene Output Resolution
The Scene Output Resolution options allow you to define the output format and resolution for your rendered frames.
To set the output format and resolution
Do one of the following:
Choose a format from the Preset list.
or
Click the Output Formats button.
This opens the Output Format property editor, where you can choose a picture standard and update all applicable parts of the scene with your changes.
For more information, see Setting Output Format Preferences
You can override the scene-level Output Resolution settings to set different output resolutions for particular passes. See Setting the Pass Output Resolution.