Have been trying to use a 550ex & 420ex combination and am having real trouble trying to meter the flashes. I'm using a Minolta IVF flash meter and I think the preflash on the 550ex is giving me a false meter reading...very low. The 420ex seems to only fire as a slave light when the 550ex is set to ETTL mode. I can't get the 420ex to flash in either Manual Mode or Multi. There is obviously something I am doing wrong in this setup. I would just like some info as to how best to set up a 550ex/420ex master/slave system; how I can get an accurate meter reading of the system output; and what i need to do to get the 420ex to slave in both Manual Mode and Multi. Would also like to know how I can test fire the system to check the meter readings. Thanks.

-- Lex Bowden (lex.bowden@vicpointss.qld.edu.au), May 07, 2002

Answers

The whole point of a computerized automated system like E-TTL is you just use it and hope it works - you aren't supposed to meter it. And given all the preflashes for E-TTL and wireless commands it's pretty hard to do any halfway reliable metering.

I don't know if you can get the 420EX to slave in manual mode - the 550EX has manual power output settings but the 420EX does not. Slave flash in stroboscopic (multi) mode doesn't make much sense to me.

-- NK Guy (tela@tela.bc.ca), May 08, 2002.

NK Guy's right, there's no good way to do this and there's no good reason to either. You just put film in the camera, shoot it & see how it turns out. It usually works fine.

The E-TTL metering preflash can be ignored while using a falsh meter if you use FEL first, then set your meter and then fire the shutter. But this doesn't work with wireless mode because of the additional communication preflashes used to trip the slave flash.

And I don't think that the 420EX will work in wireless manual mode, but maybe somebody else knows something about how to do this. I know you can do it with two 550EX's or a 550EX with a Sigma EF-500 Super.

-- Jim Strutz (j.strutz@gci.net), May 08, 2002.

In short, you can't test fire your system and use a flash meter.

First, as you have found out, the Minolta IVF meter simply reads the E- TTL's low power preflash and renders a false reading. Flash meters are not intended for use with E-TTL, A-TTL or TTL Speedlites. Why? The flash meter inside the camera is already in control of the flash duration. Flash meters are mainly used for studio strobes which are controlled with manual power settings.

Furthermore, the 420EX can only be used as a fully automatic E-TTL slave while in wireless mode. You can set lighting ratios on the 550EX or ST-E2 for the 550EX and 420EX, use the modeling light, set High Speed Sync, FEL and Flash AE Comp. Only the 550EX is capable of manual power settings. I used to use a Minolta IVF meter in my school's studio with studio strobes; however, the evaluative meter and E-TTL is faster and more flexible for portable use. I've had great results with a 550EX. 420EX and ST-E2.

So, lose the flash meter, position your Speedlites, set ratios and you'll get well exposed images. Study the results and start tweaking.

-- Puppy Face (doggieface@aol.com), May 08, 2002.

The standard answer is "It can't be done". The 420EX cannot operate as a manually controlled slave. For that you need another 550EX. But there are alternatives.

If you MUST have manual flash metering, you can drive the wireless system at full flash power, and adjust your output by positioning your flash, bouncing or filters. Then you can use the TEST fire button on the individual flash unit for metering.

One way is to use optical slave hotshoe triggers controlled by a standard TTL flash (e.g. popup flash or 550EX wtih CF3). The slaves will then fire in manual mode, but most use an SCR circuit that will "lock" after every shot. You have to turn the flash OFF and ON to reset the trigger :-(

Another, simpler, way is to make use of the E-TTL system features. Cover your lens and viewfinder then activate FEL (Flash Exposure Lock). This will cause your camera to detect "flash underexposure", and drive all the flash units to full power.

So, it is possible, but probably not what you wanted to do.

-- Julian Loke (elan7e-owner@yahoogroups.com), May 08, 2002.

Hey thanks for the suggestions everyone. I was hoping there would be a simple answer...and I guess there is. Dial in ETTL and just trust the technology works. A couple of test rolls should confirm that anyway. Cheers

-- Lex Bowden (lex.bowden@vicpointss.qld.edu.au), May 09, 2002.