Increase Samples (or iterations?)

Defenistrat

I have been trying to render an Iray image for a few days now. I'm rendering it fairly large, and there is some lighting and atmosphere (sickleyiled style) that I think is making the scene more complex, but I'm hesitant to remove it. Yesterday, after two days of rendering, it hit 15000 samples and stopped, but it's still rather grainy. So I made some changes, upped the iso, as I read that a brighter image renders better, and am trying the noise reduction enabled (but that's just me guessing), and started a new render. I looked at it this morning, it's at 8000 iterations, and looks like it will still be grainy. Is there a way to increase the samples, or as I have read they are not the same thing, can I increase the iterations past 15000? Thanks

Tobor

Iterations and samples (really sample passes) are the same.

The noise reduction may or may not help in degraining the image. This feature doesn't work in the way most people expect; however, it may only "kick in" toward the end anyway.

To increase the samples, review the three "stop at" settings:

* Convergence ratio

* Max Time

* Max Samples

Generally speaking, even on a CPU-only system taking 2+ days to render an image isn't very efficient, and if you're running at 100% cores during all this time, you may be doing some long-term damage to your computer. Consumer PCs weren't made for this. You should consider eliminating or changing those scene elements that are causing the issues. Atmospheric effects can almost always be added in using Photoshop or some other graphics program, for example. And, with the right brush set, like those from Ron Deviney, tend to look better than rendered atmospherics, anyway. 

fastbike1

It really isn't a brighter image (e.g. tone mapping) that renders faster, it's an image with more light(s). Tone mapping can get the look you want, but it isn't making an impact on render time.