We decided that we would render our animation out in Mental Ray in Production Quality but turning on some additional features. The features are Raytracing, Global Illumination and Caustics. We chose to render all this out in High Definition 720HD. That equates to a resolution of 1280 x 720 pixels. Due to choosing these high quality render settings we had to make sure that we leave enough time for rendering. We did some test renders also using final gathering which gives even more realistic lighting conditions. However it also dramatically increases render times. We did a couple of test renders of our outside street scene and the render times for one frame were usually about 15-20 minutes. This can be seen in the screenshot below.
Upon completing this test render we decided we would only use final gathering on the smaller indoor scenes where we would see a real benefit from final gathering. E.g. The reflective surfaces in the kitchen etc. But not on our intensive outdoor scenes where the benefit of final gathering wouldn’t outweigh the increased time for rendering.