The last series of images (the greyscale types) are single light (infinite), colour is white, strength is as listed, varying from 100% to 6400%.

Skydome is normal, non HDR image, just a jpg on a dome, and ambient values are the only thing that changes, from a value of 1 to a value of 64, as listed in the scaled image.

They are the ONLY light sources in the images.

The talk about f stops is because I am equating Poser to an old SLR camera, and how with the real thing, moving up a stop doubles the amount of light hitting the film, and so is an exponential progression, and hence this test to see that in fact it DOES work the same way in Poser/Firefly.

I hope SM does eventually put exposure options into the camera settings within Poser.

There is no standard to this, just as there isn't with a normal camera. Each situation will be different. The last image I posted worked at 3200% and ambient of 32 for the skydome, but the first image I posted at the very beginning of the thread was too dark at a light setting of 6400% and ambient on the skydome of 64.

This was all about saying, if you have used an SLR camera, that this approach will get you to a ballpark approximation of good lighting more accurately and more quickly than just guessing, which is what I had been doing until now.