Instruct: Classify an Amazon review into positive or negative sentiment.
Query: Don't buy those umbrellas just yet

I'm primarily a street photographer, and my studio lighting set up has for years involved umbrellas and reflectors. However, this book demonstrates- without actually stating it- how little control this offers the photographer. (Umbrellas are still useful, but they are not always the best solution.)The technique of varying not only the source to subject distance but also the origin to source distance is worth the time and money I invested. (The source is your light modifier. The origin is the light itself.)This is not for beginner photographers or even those new to studio lighting. The author assumes a good knowledge of photography and a basic knowledge of studio lighting. In fact, I feel the need to read it again.I give four stars and not five because I felt that there could have been a few more chapters.Note: the title is NOT "How to Choose and Purchase Photographic Lighting". The book is about how to USE Photographic Lighting.