I have had several scenes where the preview was so different from the render (this is without any rendering optins on - just the stock low-end quick Firefly render) that sometimes it has been frustrating. Very occasionally, I have actually preferred the tones in the preview and then I was in real trouble as I have never been able to figure out how to make them agree. I'm attaching a before-and-after of a test I did this morning that shows the preview as very green (and red!) in comparison with the render. The reddish sideleight is also much more pronounced in the preview than in the final render. I prefer the render in this case for a lot of reasons, but can someone point me to a tutorial somewhere or something that will tell me how to make the preview approximate the render better? I'm a professional photographer, and honestly, at times Poser's lights drive me crazy - they absolutely do not behave like lights in the real world and it can be exasperating.

I won't even pretend to undersatnd poser lighting, but, assuming you're using the auto settings in Poser 8 for Firefly the really low setting don't cast shadows or use ray trace - so when you crank it up you are completely changing the way light is rendered. For poser 8 preview renders I never go below the half way point on the slider - this will keep cast shadows and ray trace turned on.

Your side light here is below the ground. Preview doesn't take shadows into account, so the red light is visible in the preview. But in the render, the ground blocks the light so it doesn't do anything. The render isn't unrealistic, the preview is. And if you were setting a stage for a photograph, you wouldn't be placing the light under the floor like that.

Preview is meant to be fast, not accurate. So the lighting model used in preview is really oversimplified. Light data doesn't take into account shadows and spotlights don't accurately portray the cone of light produced by the spotlight settings.

Also, the color of each pixel is not decided by lights. The color is decided entirely by a shader.  (materials) The information coming from the lights is only a hint to the shader about what it should do. The shader can do anything it wants with the light. Shaders can produce bright colors where there is no light, and can produce black even in the presence of a blazing spotlight. While light settings and placement are important, the fact is that you find them unrealistic because your shaders are non-photoreal.

Usually we use shaders that use the light data in smart ways to decide what color each pixel is. Such shaders are called photoreal, because they are meant to be making decisions that mimics real life as seen in photos. Non-photoreal shaders (NPR) do not make the right decisions, but they are usually very fast. 99% of Poser content has stupid NPR shaders on them. And the preview versions of the shaders are entirely NPR.

The shaders that are used in preview are much simplified versions of the shaders used in rendering. Even if all you do is hook up a texture map to the Diffuse_Color and dial in some specular, the preview version of that is grossly oversimplified. Not only are the preview shaders ignoring shadow data, they also do not generate the same answers even if you turned shadows off in render.

Preview shaders also do not generally show anything regarding bump or displacement, and only use low-res versions of the texture maps. And nothing involving raytracing (reflections, refractions) is dealt with in preview.

Photoreal shaders are math-intensive. You don't want them in preview.

If you go beyond a simple color map and simple specular effects, i.e. you use some nodes in your shaders, then the preview has no hope of matching the render in any way.

Your scene looks pretty simple and probably has no nodes in it, but I do see bump and shadows. That alone is going to make it different.

Yikes! I need to copy that and paste in into my reference notebook (which I keep for all my complex software). That explains a lot and it points me in directions that I need to understand better. I have watched the video tutorials on Poser and am dismayed to find that they almost totally ignore this kind of information on lighting. Of all people, I certainly understand just how important it is to get a handle on it in this program. Thanks very much for your considered and detailed reply. 

Benboom, let me give you a quick bit of advice from a reasonably new poser user - find everything you can in these forums that Bagginsbill has posted - my poser bookmarks folder is full of links to his stuff from these forums. I started out, like I do with most new software reading the books and experimenting, I wasted a ton of time ! days spent reading thru the forums ( especially BB's stuff ) is like months of trial and error.

I've actually use an antiailiased preview for some animations because I liked the way the preview looked over the rendered scenes. It doesn't hurt that it is ten times faster than fully rendering it. What I hate is when I buy a set and it looks horrible rendered but fine in the preview. I recently needed a TV news set and bought one from the marketplace here and it doesn't render.  Perhaps I can hijack this thread for a bit and see if anyone can tell me why it renders like this (top is highest setting on Firefly and bottom is antialiased preview):

My first instinct would be to check that Normals Forward is checked in the Material Room.

Quote - My first instinct would be to check that Normals Forward is checked in the Material Room.

That did it. thanks!

Bagginsbill, you never fail to teach. All of this would have been a hell of a lot easier if you had written the Users' Guide.

I recently set up a scene, everything looked great in the preview. When I rendered, it was black. There was a wall in the way of the camera when I rendered, that was not in the way in preview.

How long does it take for you to render the scene? That is how slow preview would be if it produced the rendered results.

lmk