I was wondering if there is any way to disable the 380EX ETTL pre-exposure flash.

My friend wants to do portrait work with his Elan II, a 380EX and two older canon speedlights. The two older lights (I think they are 199A's?) will be set up on light sensitive triggers. When the pre-flash goes off, the slaves fire during the pre-flash metering (I think this would be a problem).

I understand that you can use flash exposure lock (FEL), wait for the slaves to recharge and then take the shot. It seems that not only would the metering information be thrown off by the pre-flashes, but this could also be quite confusing and disorienting to the person being photographed.

Can you disable the ETTL on the 380EX, hence killing the pre-flash? I have told him to buy a mixed bag of 420EX's, 550EX's and a transmitter, but he does not like that option. A little too costly, for him and me.

I am fascinated by this problem.

The other option would be an ETTL distributor and a couple more 220EX's or 380EX's? Technology is great, but it sure can be hard to mix and match decades, years and months.

-- Roger (rashrader@hotmail.com), February 05, 2001

Answers

I recall a post concerning this recently. Try taping off all but the center pin of the flash with black electrical tape. You will lose any control over output (your 380EX will throw a full dump every time), but your preflash will magically dissapear. Or you could buy a Wein Safe-Sync and use the 199A units alone. Don't ever attach the 199A units to your EOS body without a voltage reducing device. The voltage emitted by an older flash unit can be as high 120 volts. That will fry your EOS. After the Safe-Sync is attached to the hot shoe, you can run a PC cord from the Safe-Sync to any flash safely. Coincidentally, the Nikon screw mount PC is the best way to attach stuff to the Safe-Sync. Some very controllable Vivitar 285's would be better IMO. You have no control with the 199A's. The 199A's could be used for a background or hairlight. If they only have their one output, that could be the baseline for setting up the other lights. Hairlight at f/11, main and background at f/8, and front fill at f/5.6 would be very easy.

-- Colin Miller (ckmiller@pond.net), February 05, 2001.

To disable the preflash of the 380ex, attach a TTL hot shoe adapter 3($60 at B&H) to the camera's hot shoe and then the 380ex on top of that. This will disable the preflash and give you additional sync outs if you want. Or... simply use a non-E-TTL flash (non ex).

-- David Bindle (david.bindle@usask.ca), February 05, 2001.

Don't ever attach the 199A units to your EOS body without a voltage reducing device.

Not so - the 199A trigger voltage is safe for use on EOS bodies. From the Canon Speedlite Reference Guide (1991):

 Older (non-TTL) Canon Speedlites:

This includes 577G, 533G, 299T, 277T, 244T, 199A, 188A, 177A, 166A, 155A, 133A, & 011A. These flash units, though dedicated for older Canon SLRs, are not fully dedicated for the T90 or any of the EOS cameras. However, they can be used with the T90, EOS-1, RT, 10s, 630, Rebel, 620 & 650, by selling the camera's shutter speed and aperture manually. (Shutter speed will be automatically limited to maximum sync speed* or you can set a lower speed manually.) Automatic, non-TTL flash exposure is possible by setting the Speedlite to an automatic mode and setting the recommended lens aperture yourself.

The advice of the use of a TTL Hot Shoe Adapter is good, although and older, second-hand HSA (original) or HSA-2 would suffice.  Probably the best solution is to mount one of the 199A's on the EOS body (set shutter speed and aperture manually) and the other 199A and 380EX on the slave triggers.

-- Dave Herzstein (dherzstein@juno.com), February 05, 2001.

>"The other option would be an ETTL distributor and a couple more 220EX's or 380EX's?"

There is not E-TTL distributor. There is a distributor that is a part of Canon's modular TTL cord system, but as has been mentioned using the hot shoe part (HSA ( or 2 or 3)) will disable E-TTL along with it's preflash.

Also the problem with using the 380EX (or any E, EX or EZ series Speedlite) on a regular slave sensor is that it usually doesn't work. Most of the time it fires once and then quits until it's been reset. However, some combinations of Speedlites and slave sensors do work for some reason.

-- Jim Strutz (jimstrutz@juno.com), February 05, 2001.

I use a small piece of a Wratten neutral density filter over the slave's sensor. How much you need will depend on the slave you're using. In my case, it took two layers of a .90 filter. This keeps the pre-flash (and in my case, the ST-E2's IR flash) from triggering the slave but it will still trigger when the regular flash goes off.

Paul

-- Paul Ferrara (paul@columbusoft.com), February 19, 2001.