BTW, I just found what caused the lighting difference. When I imported the scene into Max, I chose the keyboard entry option with point of origin at 0 0 0 and Scene Scaling (under Keyboard Entry) set to Real Life. But under the Scene Options I had Scene Scaling set to manual at 0'0.0" (which appears to come up as the default for me). That is what caused the brightness. When I changed the Scene Scaling under Scene Options to Real Life to match the setting under Keyboard Entry, the lighting matched that from Poser. So this probably falls under the category of user error.