Setting Up Scale-Output Nodes

Once your Write nodes are connected, if you want one of your renders to be smaller than your scene's resolution, but have the same aspect ratio and contain the same camera frame, you can use the Scale-Output node to shrink the image output by your scene's composite before it reaches the Write node.

You can use a Scale-Ouput node in conjunction with a Crop node to produce a render that is in a different resolution and aspect ratio than your scene's. For example, if you want a scene in HD 1080p to render in NTSC, you can use the Scale-Output node to scale down the image to 960 x 540 pixels, which matches the NTSC resolution height, but has a greater resolution width to preserve the aspect ratio of HD 1080p. Then, you can use a Crop node to crop the image to 720 x 540 pixels, cropping out the image in the left and right edges to make it fit an NTSC screen.

NOTE: If you use a Scale-Output node to scale up the image, it will look pixelated. If you want to export a scene in multiple resolutions, you should set your scene's resolution to be the highest resolution in which you want to render, and use Scale-Output nodes to scale down the output.