G'Day Atillio, I thought it was useful and easy to understand, a lot of photographic writing is way to technical for novices. Just about to drive out the gate, heading for Thailand for a couple of weeks, meeting Heather in Bangkok, if the stars align we should both arrive within a couple of hours, she is flying from Rome, just did a 10 day art workshop in Tuscany. Talk to you when we get back. 🙂