Trying to understand exposure with off-camera lighting

[peachy]

I just got my new strobe (yay!) and I'm trying to learn how to use it. For now I'm mostly just using it on-camera, bouncing off walls and ceilings. Really just getting a feel for it. But!... I'm reading through the stuff on Strobist, trying to get a better understanding of off-camera lighting (I can't actually do anything off-camera yet... Santa isn't bringing my Cactus triggers until Saturday ).

Here's what I don't get... it seems like he says to always set the shutter speed to its max sync speed (1/200 on my Rebel), and then that will somehow magically expose the background correctly? I think I'm missing something...

Using what I know from just using available light, I thought you'd have to choose the right combination of shutter speed, ISO, and aperture to get the background exposed correctly, then set the power of the flash, as well as the distance from flash-to-subject, to correctly expose the subject. Is this right, or am I missing some subtle, important detail? It just seems to me that he only talks about shutter speed, but I don't see much about ISO or aperture... perhaps it's just implied?

Thanks, y'all!

[inkista]

Your assumption is right, and yes, the iso/aperture is implied.

The max. sync speed thing is because with manual triggers (like the Cactus V4s) you won't have high-speed sync capability, or if you are using TTL-capable triggering, you won't be losing light and having your batteries chewed on by high-speed sync. And also, shutter speed being your only independent control to balance ambient vs. flash, giving the shutter speed is sometimes a good indication of how someone's balancing the two.

The one thing you haven't actually accounted for is that there are going to be places where the flash and the ambient are going to overlap and combine. So, while you could go for setting exactly for what the ambient meters, a lot of folks tend to underexpose by a stop or so to make some room for the added flash.

[peachy]

Ah, good point about the areas where ambient and flash will be combined! Thanks for the helpful info