Location:
The Render Manager > (select a pass)
Set the current pass and choose Render > Render > Pass Options or Pass > Edit > Edit Current Pass from the Render toolbar.
Tab: Output [Properties Reference]
Options: Pass Output Resolution
Output Resolution options, which allow you to define the output format and resolution for your rendered frames, are specified in the scene render options. You can override the scene-level Output Resolution settings to set different output resolutions for particular passes.
To set the pass output resolution
Make the pass for which you want to override the Output Resolution settings the current pass.
From the Pass Output Resolution options, check the Override Scene Render Options box.
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.
or
Click the Update From Camera button to match the pass' output resolution to that of the pass camera.