Quote - As far as Poser is concerned, seeing the background through refraction is not at all the same thing as directly seeing the background. So those pixels are no longer considered transparent.

If you're going to composite in post, then you don't need the lens at all, do you. I mean, the point of the lens was to avoid postwork.  If you intend to do postwork, particularly compositing, then why bother with the lens? To do a proper job of compositing, you'd want to adjust levels and tone the render against the background. My preference would be to avoid postwork altogether, which means I always render with my background in place in 3D, on a one-sided square or on an environment sphere. If I were of a mind to, I could also render in a picture frame, or signature, or other things.

If you have Poser Pro, then using PPro GC is superior to the lens. When you enable PPro GC, it will also fix your incoming material. Which means you won't get washout, which means you won't need the saturation boost. I suggested using the lens for GC when you do not have Poser Pro and you have to GC in post.

Ah, I was under the impression that the gamma correction results were the same with either method, but doing the saturation boost in Poser with the Lens was better than doing it in Photoshop, but even that isn't necessary. I guess I've been needlessly increasing my render times for a while now. Good to know.