[Steve Roberts] "Do I need to do a levels (computer to studio) conversion to change my black and white levels or does the Main Concept codec do this compression for me ?"
MainConcept will clip at 16-235 so you won't get illegal levels but the proper way to do this is to adjust your levels to not be illegal in the first place. I would use Levels with the Computer RGB to Studio RGB preset because it will "scale" them to be within the legal limits instead of clipping (which is may leave undesirable effects).
~jr
http://www.johnrofrano.com
http://www.vasst.com 
