adding overscan?

[Liz]

Hi everyone!
How can I add overscan to a render in Terragen? I've noticed that when I increase the format, it just makes the image larger rather than expanding the boundaries.

[Kevin Kipper]

What I've done in the past is to increase the image width and height by whatever percentage of overscan I want, then modify the camera Focal Length in mm parameter by that percentage as well.

For example, if my original render resolution was 1000 x 600 with a 40 mm lens, to add 20% overscan I would increase the render resolution to 1200 x 720 and decrease the focal length to 32 mm.  

[Matt]

You can decrease the focal length as Kevin said, or leave the focal length as it is and increase the "Film aperture in mm" values. For example, to add 20% overscan you can either divide your focal length by 1.2 or multiply the film aperture values by 1.2.