New to wireless flash - SB910 questions

fjrabon · Dec 9, 2012

Also, I think earlier you asked why anybody would ever use SU-4 instead of advanced.

SU-4 is more sensitive, so you can get more range. ie in some situations your flash may not be able to sense an AWL signal, but if you flip over to SU-4, it will, and thus you don't have to pull out the radio triggers. I find this especially helpful when I have one distant flash that there's no way in heck it's going to pick up the AWL signals, BUT it will pick up when the slave units fire, and then will fire itself off the slave units instead of the controller's AWL signals.

AWL allows you to use TTL, and/or control the power level of the flash directly from camera, whereas with SU-4 it doesn't. I don't believe AWL lets you control zoom though, but I could be wrong about that. I think it takes too long to adjust zoom for it to really work with AWL. I THINK you have to adjust zoom manually on the flash.

greybeard · Dec 11, 2012

SU-4 senses when the triggering flash starts and stops so it mimics the output of the flash that triggers it. You don't want the trigger to be emitting any pre-flashes like with iTTL as the pre-flashes will trigger it before the shutter is open. I'm sure it has it's uses, I just haven't found any that pertain to me.

Vautrin · Dec 11, 2012

SU4 is useful in some situations. Dial in the exposure you want from the flash and itll flash when another flash does

I use it to create "dramatic" effects. For instance sometimes i want under exposure on a certain part of the shot

I actually find it more useful than commander, but thats because im a control freak

fjrabon · Dec 11, 2012

greybeard said:
SU-4 senses when the triggering flash starts and stops so it mimics the output of the flash that triggers it. You don't want the trigger to be emitting any pre-flashes like with iTTL as the pre-flashes will trigger it before the shutter is open. I'm sure it has it's uses, I just haven't found any that pertain to me.

You can set it to either use the 'TTL/auto mode' which you're talking about (which isn't TTL, but some people call it that), or pure manual, where it senses the flash and then fires at whatever power the unit itself is set at.