Can anyone here help or direct me to some resources to understanding flash photography and flashes... There are so many features on the flash, but I am not aware on how to and what maybe more important - why to use them I have a very old, Nikon SB-600 and Yongoo (910.. something) Have no manuals for either, but ,, never the less. I understand the words on the controls, but I do not know what I may need that or this button for, What I am asking is: How can I design my mental path, to know that for this-that -and-such, I would need to do certain things on the flash ? SO the question is not really about how to use a flash technically, but more on what does it do for me, and do I recognize the need for a particular feature ? Maybe books/articles ? any educational resources ?