I am using Karma to render an object in the viewport. It takes 10 seconds and looks fine. When I use the Karma ROP to kick out that same image, it takes two minutes?

What gives?

How can I get the same performance from the viewport in my final render?

Answer: Your render output size is larger than the viewport render size. Make your render size smaller to obtain the same performance.

Could you send us a sample file? Are you sure you're using the same number of pixel samples? Same resolution?

The file is posted on your tutorial page. It's the Tyler Bay shaderbot example file.

Once again, I'm wonder what you mean by using the same number and size? There is only one pixel sample field and one size field on the Karma ROP, right? I have the Display flag on that ROP and the viewport seems to be using all those settings.

The Pixel samples on the Karma node are set to 5 on the ROP. H18.0.416. This setting causes the viewport to finalize in about 11 seconds. When I render to disk, it takes over 2 minutes.

Is the viewport rendering a far smaller image?

Not too much smaller, here is the viewport stretched out a bit, and it takes 20 seconds.

The wrong Gamma is more of an issue than the time, but I take it this is not normal.

How did you end up with the wrong gamma?

I think what is happening is that the TIF processor is defaulting to gamma 1.0 linear. It would be nice if us end users could override that to 2.2. Otherwise, I have to reprocessing the image sequence in another app.

I notice that if I render to a JPG (which isn't even in the drop down list), I get that file format's default gamma of 2.2. I'm not really kicking out AOVs yet, so I'll probably use JPG output in LOPs.