okay everyone

thanks for the support. I got the answer doing some measurements, with just Gamma=1 (red) and gamma=2.2 (teal), and also exponential tonemapping added to them, with expo=1.6 (default) or 3.2 (double exposure). Measurements were made in all six cases, in three rounds with varying lighting conditions, and 9 points per round.

My conclusions:

1. when you want to post process the image, especially when exporting to HDR or PSD or working with render passes in any other way, tonemapping as well as gamma should best be off. This matches Robynsveil's linear way of work. you might take the teal curve (is about  [0,0] [20,50] [50,75] [80,90] [100,100] ) for curve adjustment in Photoshop.

2. when you want the image just to look good without that much postwork, gamma is fine and 2.2 does the job by pumping more dynamics into the dark areas as shown in the mirror-example by BB in this thread (teal curve). However, no gamma but a serious exponential tonemapping does a similar job (green curve).

3. applying exponential tonemapping with 1.6 leaves the overall luminance of the image at the same level, but adds some detail to the darks while taking out some from the hilights. This is great for fashion shoots where usually the model is mildly overexposed to shift the attention to the clothes. It works just on top of the gamma effect (orange and blue curves).

4. tonemapping and gamma add on to each other, both pump up the darks at the cost of losing detail in the hilights. Gamma is stronger on increasing the nuances in the darks and handling underexposure, while tonemapping is stronger in reducing detail in the hilights and handling overexposure.

So, do I need gamma, and are there alternatives? Well, the final result will profit from a "serious and non linear brightness correction", that's for sure. This can be done in post, in Poser GC and in Poser tonemapping, in any combination. Doing none of them is a shame. Poser GC is a convenient way, but not the only one.

When I consider more detail in the darks the most relevant improvement to make the result look good without detailed postwork like curve adjustment and render passes, Poser GC is the way to go. Postwork instead requires the right adjustment curve and more, but is the most flexible, and the most efficient way to find the proper settings interactively. Tonemapping is an alternative that makes reducing the hilights as the most relevant improvement instead.

Take your pick.

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Usually I'm wrong. But to be effective and efficient, I don't need to be correct or accurate.

visit www.aRtBeeWeb.nl (works) or Missing Manuals (tutorials & reviews) - both need an update though