ST-E2, 580EX M mode and 420ex with ratio?

[incendy]

If I have the 580ex on channel A and set to Manual Mode and the 420ex on channel B will my ratios on the st-e2 still work? Basically trying to come up with some way to use the 420ex with my other lights without it doing its own thing

[incendy]

ok, in theory this sounds like it would work, but it doesn't The first couple of tests seems to work cause I had the main light with the right power and the ettl was fill, but then I purposely set the main light to underexpose by a large margin and ettl still kicked in on the 420 to expose the shot. Time to sell the 420

[In2Photos]

Yeah, the 420 has no manual mode so won't work good for this application. Step up to the 430 or another 580.

[PacAce]

Originally Posted by incendy

If I have the 580ex on channel A and set to Manual Mode and the 420ex on channel B will my ratios on the st-e2 still work? Basically trying to come up with some way to use the 420ex with my other lights without it doing its own thing

I don't have the ST-E2 so I can't tell you for sure that it should work, but when I use my 580EX as the master, without firing the flash and in essence emulating the ST-E2, and my 550EX as Slave A set to manual mode and my 420EX as Slave B in, of course, ETTL mode, I can set the A:B ratio to whatever I like and the 420EX fires accordingly. I would imagine that the combo should work the same way with the ST-E2, too.

[PacAce]

Originally Posted by PacAce

I don't have the ST-E2 so I can't tell you for sure that it should work, but when I use my 580EX as the master, without firing the flash and in essence emulating the ST-E2, and my 550EX as Slave A set to manual mode and my 420EX as Slave B in, of course, ETTL mode, I can set the A:B ratio to whatever I like and the 420EX fires accordingly. I would imagine that the combo should work the same way with the ST-E2, too.

Let me expound on my previous post. When you set a 580EX to manual mode and power is adjusted on the slave flash unit, the only function the master provides is flash synchronization. So, when you have the A:B ratio set and the other flash in the combo is set to ETTL mode as is the case with the 420EX, the output of the ETTL flash (the 420EX) will be determined by the ratio setting based on what the Group A flash would have put out if it were also in ETTL mode also. In other words, the 420EX output is not going to be based on what the 580EX is set to in manual mode since the master has no way of knowing what that is (a slave in manual mode does not fire a preflash).

If you were to use another 580EX as the master, like I did earlier, then you will be able to control the manual output setting of another 580EX or 550EX slave (which are in ETTL mode) from the master itself by setting the master to manual mode. However, if you do that, then the 420EX won't work in this combo because the 420EX does not have manual mode capability. It'll only work when the ST-E2 is used or the flash used as the master is set to ETTL mode.

[incendy]

Thank you PacAce! That clears it up for me really well. I need to get rid of the 420, was just trying to use it cause I am trying to save money for other things, but I am finding for what I want to do it just doesn't really work for me