Thank you very much! I really appreciate the time and effort you took to write all of this out! It is very useful information, and should get me well underway. I have read that these devices used to come with a calibration negative, and your suggestion about the ND gel effectively explains how to replace it. I have ordered the ND gel, so it will be a few days before I can try out your suggestions.

One follow-up question if you do not mind: you suggested that I email roger and get the instruction manual. Please excuse my ignorance: who is roger?

Thanks again!