550/580/ST-E2 Manual Mode

Wanting to have a little bit more control, I decided to try my 550 & 580 flashes in manual mode. I normally use them in ETTL mode with good results. I trigger them with the ST-E2.

After going over the manual again, I figured out that holding the Mode button down for 2 seconds allowed you to change the flashes to M mode when they're slave . Great. Good start. I set my 20D to 1/60 f/22. In slave mode 1/1 my 550 only gives me a reading of 1/60 f/1.0 on my Sekonic 558R when triggered by the 20D with the ST-E2. The ST-E2 always shows the ETTL light. If I manually fire the flash from either the ST-E2 or the flash itself, I get a reasonable reading like f/22. I tried turning off the preflash with the 550 CF 3-1 and using FEL to fire the preflash.

It seems like I'm getting a short pop when firing the shutter, but a full pop on test from either the ST-E2 or the 550. What am I missing.

When you test the slave 550 with the 558R, did you push the test button? Because by default, the test button fires only 1/32 of the flash power.

Are you sure on that? I get a louder pop when I push the test button, and the 558R reads closer to what I would expect, like f/22+ at about 4-5 feet. I think you get the low power pop when you have the flash set to ETTL. I have it set to M-1/1, so I would expect something close to full power.

Opps, you are right about that when in slave or manual mode. I don't have a ST-E2, can you try to use the 580 as master on camera and do the same test?

When ETTL wireless remote is used, whether the flashes are in manual mode or not, there is always a preflash (which carries the wireless remote control signals) fired by the master just before the shutter opens. This must be what your L-558 is registering. I know if you were using the 580EX as the master, that's what it does. Since the ST-E2 does not fire any visible light (only IR), I'm assuming that the l-558 must also be sensitive to IR light and this is what's being measured. I know that it's not from the slave because in manual mode the slave does not fire a preflash.

If I get time today, I'll try it.

I seem to get a reasonably correct reading if I use test from the ST-E2. Wouldn't it send out the same control IR? The readings are only incorrect when I fire the camera shutter.

Time for a notepad and some experimentation....

There is an option to test fire with autoflash to use full or 1/32 power with the 580ex

c.fn-09
0=1/32
1=Full power

This applies to the pre-flash in ettl and ttl as well as the test fire button... In manual slave mode, the 580ex test fire button fires the strobe at the power output selected on the display.

I didn't find anything in the 20D manual about what power output is used for the FEL pre-flash. If you are using manual flash mode, I don't think it would be apropriate to use the camera's ettl FEL pre-flash button to trigger the slave flashes for metering purposes.

It would be a nice but it doesn't apear to be designed to trigger slave flashes for off camera manual flash metering.

In that case, the only thing I can think of is that when you use the test button on the ST-E2, the slave fires almost immediately upon seeing the command signal from the ST-E2 so that the light meter is able to register both the command signal and the slave test flash within the meter measuring window.

In the case of the camera shutter firing the flash, the master has to send out the signal before the shutter curtain opens. The slave then has to wait until after the curtain opens all the way before it can fire the flash. This interval might be longer than the measurement window of the flash meter. I'm just speculating here, though, since I don't know this for a fact but it seems logical enough to me though.

Since the 580ex is not connected to the camera, the camera does not know what mode the flash is set to, the st-e2 does not know what mode the 580ex is set to either. When using the FEL button on the camera, the st-e2 instructs the slaves to use their ettl pre flash for ETTL metering with the cameras internal light meter, since the camera has no power option for FEL pre-flash this will not work with an off camera flash meter because there's no option for slave trigering for off camera metering.

A custom functions option for full flash output with the FEL button would work nicely for what you are doing.

If you're gettin the same pre-flash meter reading from the 558R when you press the shutter as when using the camera's FEL what pacace mentioned makes sense.

The camera telling the st-e2 to pre-flash for ettl exposure metering, since the st-e2 is stuck on ettl all the time it makes sense that the 558R flash meter window is closed after the pre-flash.

Since there is no manual control over the camera's FEL output via custom functions, or manual override of the FEL signal into a "TEST" or "FULL" state with the st-e2 You will have to stick with using the test button on the st-e2.

The online documentation of the 558R flash meter mentions an accumulative, and non accumulative metering mode. Check those options, see what results you get, also try the meter with the flashes off to test if the st-e2 IR emmiter is triggering the flash meter.

I only tried the FEL to see if there was any difference between the 550 CF3-1 which turned off preflash. I never tried measuring the flash when hitting the FEL, only the flash using that setting.

The more I think about it, I think the ST-E2 doesn't know that the 550 is in manual mode, since the ST-E2 ETTL light is ALWAYS lit when connected to the camera.

I tried both modes, and it never shows more than 1 flash, at the low reading, which I think is true.

Maybe I'll try taping the hotshoe contacts to turn off the ETTL.