12-02-2014 04:06 PM - edited 12-02-2014 04:10 PM
Stupid question... but what's a good definition of "group" in terms of flashes? That has me confused.
Well, it's a group of flashes, although a group can have a single flash in it. It's a way to organize sets of flashes for adjustment. Every flash in a group will have the same power settings. But if you're only using three flashes, then you'd probably give each flash it's own group (although IIRC Canon has some limitations as to what you can do with Group C in eTTL).
In eTTL mode you set power ratios. For example, you tell it that you want Group A to be 2 times as powerful (1 stop) as Group B and 4 times (2 stops) Group C. A would be your Key light, B your fill, and C your background light (just as a general example, there are no rules). It would look like this (A:B:C) - 4:2:1 The camera then determines how much light it thinks it needs and calculates how strong to make each group given that ratio.
In manual mode you just adjust the power level of the entire group, 1/1 being full power of any flash in that group. So say you decide that your key light needs to be 1/4 power. You set Group A (a single key light) to 1/4 power, your second flash gets assigned to Group B at 1/8 (one stop less) for fill, and then you have a couple accent lights assigned to Group C that you set to 1/16 (two stops lower than A) for background lighting. These are just example numbers to mimic what was set in the eTTL example above. 4:2:1 ratio.
12-02-2014 04:57 PM
That makes sense to me now. You really cleared that up for me. And thanks for the link to the strobist site. I had run across that before, read a little on it, and wanted to go back to it but couldn't remember the name of it. You're right, there is a lot of good info there for a beginner. You're full of all sorts of good info.
Thanks again for all your help!
12-03-2014 12:55 PM - edited 12-03-2014 12:55 PM
FYI: This is the manual for the 622 I was referring to. Don't bother with the one that comes with the camera.
It says that it's eTTL compatible with the original 580ex. So that means, so long as you're in eTTL, you won't see any difference between the 580ex and 580exII. In manual mode you're have to manually change power on the 580ex, where as the 580exII and 568 II can be changed via the YN-622C
12-04-2014 05:51 PM
Thanks so much! That'll REALLY help once I get the 622s. I cancelled the 10m cord that was $71 (they hadn't sent it out yet). But what I think I'll do is just get a 10m coiled one for $23.49 and keep it as a backup in case I ever need it if the 622s get finicky. I also found a cheap pair of umbrellas I'm thinking I'll get too, just to start out with. I found a pair for $48 with translucent, gold and silver umbrellas, so that would give me 6 total to work with (links below). I'm making my way through the Strobist site, a DVD on the Canon speedlights, and the Speedlighter's Handbook now... It's hard for me to concentrate on just one thing at a time, but I'm learning a lot from each (and from you too!).