Thank you all for the responses to my question. Perhaps I was miss leading when I said I was a newbie. I apologize. I'm a newbie to posting on the site. I've been involved with photography for over 50 years. This includes photo labs with C-41, E6, B&W, custom photo printing, wedding & studio portrait photography, forensic photography, medical film photo equipment and I've worked in my personal darkroom since 1974. I work with many formats from 8x10, 4x5, 120/220, 35 and 21/4 x 31/4 sheet film formats. Each has it's own quirks and yes most of my equipment is older mechanical style. So the system of calibrating minimum exposure coupled with calibrating film, cameras, developer and film to this standard really helps me with multiple systems. I was curious how many others used the same system. Yes the system is similar to a zone system in that it gives you a standard starting point to deviate from if needed. Similar but not as involved. As a for instance with my 35 film cameras T-Max 100 is ISO 100 but with my 120 cameras it's ISO 50 to get the best negatives. Different lens, camera, meter. Again thanks for the interest and responses.