Thanks Braham for your answer. Based on your reply and other info I have got, I dare to make the following conclusion "draft". Could you please check if it is totally wrong or right. I don't have a single EX550 myself. I'm just considering buying one or possibly two if I can get this "thumb slave" problem solved. In normal cases the E-TTL with two flashes could be nice, otherwise there wouldn't be sense in bying the second EX550 I quess. So: To work (with an EOS-3) with two EX550s plus one simple dumb manual slave flash the settings could/should be the following to avoid triggering the dumb slave by the 550 pre-flash: Master 550 (the on-camera flash): - Manual exposure mode (thus no E-TTL). - Master/Slave in OFF (?) to get rid of the pre-flash. - Flash output switch to ON. Slave 550: - Manual exposure mode. - Master/Slave to Slave. - Flash output switch to ON. Uncertainty: - Does the slave 550 trigger without getting a pre-flash if it is set to manual exposure mode? - Does the slave 550 trigger without getting a pre-flash if it is set to E-TTL mode (not valid in this case though)? - Would switching the Master/Slave switch in the master 550 to 'Master' position enable preflash? If this works it also means: - Fully manual flash exposure. - No remote control on slave EX550 (have to walk then). - The dumb slave works fine (since no preflash). - The slave 550 actually works as another "dumb" slave. >Have you considered triggering the other non speedlight/EX flash from the >sync socket via cable as this only fires at time of film >exposure (as I understand?!). I will be working in darkness and on water so cables just make me angry, especially when I need to move one of the flashes or the camera, alone in a hurry (and it is raining...). Thanks, Vesa >Date: Tue, 16 Jan 2001 22:51:50 +0000 >From: Braham Hughes <[EMAIL PROTECTED]> >Subject: Re: EOS Simple (?) slave flash question. > > > I've read numerous mails about using simple slave flash > > units with EX550 in master slave configuration. > > My understanding is that any preflash triggers the > > "simple" slave (too early). > > > >yes it does > > > > > I'm now trying to find out if it is possible to use > > two EX550s (one on-camera and the other not) and an > > additional "simple" slave flash (thus 3 flashes total) > > successfully. All flashes in Manual exposure mode. > > > >It is possible, but still with pre flash to trigger the slaves if master >set to ETTL. >If master set to manual also then you're OK but you will need a flash meter >to set >exposure (aperture) > > > > > The camera is EOS-3 in Manual exposure mode as well. > > > > 1) Do I still get preflash (for communications between > > EX550s) if the two EX550s are in "Manual" mode but the > > on-camera is set to "master" and the other one is set > > to "slave"? > > > >As above > > > > > I don't even know if I can set anything in the slave > > if it is set as "slave" or does it get all instructions > > from the master flash only? > > > >In slave and manual mode the 550s are only triggered from the master, no >power/exposure info is sent. However you can set all manual parameters by >pressing >and holding the mode button until you get manual and then multi modes >selected whilst >in slave mode. you still need manual flash metering though as the slaves >only receive >trigger, no other info. Bear in mind that all ratio control is available >with the >EOS3. Have you considered triggering the other non speedlight/EX flash >from the sync >socket via cable as this only fires at time of film exposure (as I >understand?!). > > > > > 2) Does the slave EX550 flash if it is set to "M" (Manual) > > AND the Master/Slave-switch in master-EX550 is set to OFF and > > the same switch in slave-EX550 is set to "OFF" (or "slave")? > > Thus is there any setting when the second EX550 acts as a > > dumb manual slave only? > >I the master is set to off (flash output - not the master/slave switch) it >will fire >the control pre-flash, This is true in all modes as it will always act as >a master if >set to master - hence pre-flash. If you set the master/slave switch to off >this sets >separate individual flash units and thus no wireless control at all. > >Thus for any sort of master slave control you will need a single master >unit and one >or more slaves. If a master is active then there will be a pre-flash. > >And yes it can be very confusing. What I strongly recommend is that you >wait 'till >you have finished your current film then with an empty camera body test all >the >possibilities (it is just about possible to see the pre-flash - especially >if you >focus on a close light subject so that main flash isn't too bright. I >still think the >sync (PC) socket may be your answer, just be careful of metering!!! > >Cheers, Braham. > > > > > > > Maybe this was already answered but I may have missed it. > > Sorry if so. > > > > Vesa > _________________________________________________________________________ Get Your Private, Free E-mail from MSN Hotmail at http://www.hotmail.com. * **** ******* *********************************************************** * For list instructions, including unsubscribe, see: * http://www.a1.nl/phomepag/markerink/eos_list.htm ***********************************************************
