Dear list members: First I wish to say hello to all list members as I have just joined the list and this is my first post. My name is Joseph Chamberlain and I am an Oral and Maxillofacial surgeon. My interest in photography ranges from professional applications in my area of expertise to a hobby I have come to love more than any other. I hope to enjoy the group and learn from exchanging posts with all list members. My first question: I have contacted Canon for guide numbers on flash units I currently use for photo shoots. The information I was actually looking for was the maximum power output in both Watts and Lumens but (much to my surprise) Canon's technical support department wasn't able to provide me this information. How can I convert a flash guide number to Watts and Lumens ? What conversion formula can I use for this ? Thank you in advance for your help. Sincerely, Joseph Chamberlain, D.D.S. Oral and Maxillofacial Surgery
