So I have reached the point of wanting to learn to use my flash in a manner where I am in control and so I know what it is going to produce. I have been reading up on flash compensation and it seems that it is generally something to enhance or reduce the flash power, but from everything I have read it sounds like more of an after the fact adjustment for a follow up shot. Is this correct? In general I have felt my flash is too much rather than not enough, so I am going to shoot a bit with it at -2. But it doesn't seem that -1 or -2 is quite the same amount of exposure variation as actually exposing by a stop or two. Are these also considered stops? Next is 2nd curtain. First thing I noticed is at slow shutter speeds there are two flashes. Are there two at faster speeds also? For my last question right now, I don't have a speedlite, but do they allow you to set your flash for the end of the exposure?