A question of time?

glennblackphotos

Does a longer render time mean a better quality render?

Richard Haseltine

For a given image, yes  -though after a while the difference will be hard to spot. Between images, you can't really compare as they will take different times to eliminate a given amount of noise.

dijitul

The short answer is:  For the most part, yes, but it depends.

The long answer:  This requires you to determine if the render parameters you're using requires longer times.  For example, if you enable Depth of Field, it'll require longer to resolve blurred areas.  If you have a darker scene, it will require longer renders to reduce noise.  If you enable caustics, it'll require longer renders because of the additional math.

For a particular scene, you can crank up the render qaulity limits and monitor the results, cancelling whenever you're happy with it.  Renders are like camera exposures, so the more detailed information you capture, the better the image.