Does a higher resolution image require more passes?

[alexyork]

One related issue we've always found with noise levels, adaptivity and AA etc. with resulting issues in rendertimes is when you're using super "busy" stuff in your scene like scatter carpets/rugs, grass or other such very fine and busy looking geometry. It seems to throw the noise/adaptivity calculation off to the point where we basically never use noise level limit in production in most scenes, and instead do a quick manual test where you just render the whole image and draw some quick regions in the areas that are obviously struggling to clean up quickly, typically dark areas or where there's lots of reflected light or something - keeping an eye on the number of passes until it visually looks good enough to finish off with some light denoising. Then we plug that value into the pass limit and call it a day. It's the only fool-proof way we've found to get the correct quality and predictable rendertimes without leaving things to chance. But if the adaptivity side of the engine was a bit more intelligent at figuring out that it's wasting a bunch of time/passes on areas that don't actually need it, that would sure be a nice improvement! :)

[TomG]

Well, one solution is to keep all lights at a similar intensity when rendering, so they all get roughly equal importance, and then do the changes in intensity in LightMix. Similarly, keeping all lights white at render time will allow for the greatest flexibility in color changes in LightMix. Does mean your Beauty pass will be useless, but if you are intending to use LightMix, that should not be a concern :) (replying to the post before Alex's)