How to manually trigger flash?

[DSLR_Newbie]

What i want to achieve is multiple flashes in one long exposure photo graph.

so what i was thinking of is a setup where the camera takes a 20 sec long exposure shot and I manually fire flash 5 times pointing at 5 different points in the picture or stand in the picture at 5 different locations and trigger flash manually to highlight the subject. (Cheap Stroboscopic Effect i guess). so i am moving the flash from one place to another (off camera).

Do i need a special flash unit or any will do and apart from a Flash unit what else do i need to achieve this. triggers? etc.

I am a newbie to simpler the better
Cheers

[jrw]

For starters, welcome.

The first place I'd recommend checking is your flash manual. Assuming it is a Canon flash look for Multi or Stroboscopic flash. Frequency and output at a particular frequency may vary from model to model. This would be in a chart in the manual if it has the capability. The ones I've used go down to 1 Hz which should give you enough time to change aim between flashes.

Second option is to use a flashlight to 'paint' in the desired features during exposure.

Triggering could be from a cable (PC port) connecting flash to the camera body if both have ports or a radio trigger. Details on hooking up the cable can be found in the manuals or have a look through www.thestrobist.com for basic information and more advanced details on using and making cables and working with radio triggers as well. Lots of excellent information on that site for working with flash units in many different ways.

[DSLR_Newbie]

Thanks "jrw" for the welcome and the response.

As far as I know (I might be wrong) the only stroboscopic flash canon produces was the 580 EX II (rumors are it has been discontinued) and it's an expensive unit (specially in Australia with the Magical Australian Tax)

The flashlight idea sounds great for highlighting portions of the image.

Thanks for the help.
Cheers

[Agilulfo]

If you want to fire the flash five times in 20 s, it's quite simple: set the flash output manually and press the pilot button also five times.

If you haven't bought a flash yet, maybe an used 550EX could be good choice. It has stroboscopic capability, although the lowest frequency it's 1 Hz (as most of the flashes, I think).

[Sean Setters]

If you want to fire the flash five times in 20 s, it's quite simple: set the flash output manually and press the pilot button also five times.

If you haven't bought a flash yet, maybe an used 550EX could be good choice. It has stroboscopic capability, although the lowest frequency it's 1 Hz (as most of the flashes, I think).

Yep, this is a great answer. Basically, you're turning yourself into a programmable lightstand with remote trigger. As soon as you open the shutter, point the flash at different things and press the test fire button. Done.

[Dr Croubie]

Yep, this is a great answer. Basically, you're turning yourself into a programmable lightstand with remote trigger. As soon as you open the shutter, point the flash at different things and press the test fire button. Done.

I've always wondered, how much light/power output is given by pressing the test button? It certainly isn't 1/1 or 1/2, on my 430EX (mk1) I can press it a few times in a row without losing so much charge that it has to stop to recharge (battery-dependent, of course), so i'm guessing around the 1/64 mark. Can the higher-model speedlites be programmed to output a certain power from the test-button?

[Sean Setters]

I've always wondered, how much light/power output is given by pressing the test button? It certainly isn't 1/1 or 1/2, on my 430EX (mk1) I can press it a few times in a row without losing so much charge that it has to stop to recharge (battery-dependent, of course), so i'm guessing around the 1/64 mark. Can the higher-model speedlites be programmed to output a certain power from the test-button?

I think it depends what mode you're in. If you're in ETTL, then the flash is calculating the output for you (and varying it accordingly). If you have it in manual mode, then it will fire at whatever power you have the flash set to.

During one of these long exposure, multiple flash popping experiements, I'd suggest keeping the flash set to a relatively low power so that you don't have to wait for it to recycle. Typically speaking, under those conditions, you don't necessarily need anything above 1/8 or 1/16 power anyway. Set it to that kind of power or less, and you could hit the test fire button just about as many times as you wanted within a 5 second exposure and never worry about recycle times.

[conropl]

I've always wondered, how much light/power output is given by pressing the test button? It certainly isn't 1/1 or 1/2, on my 430EX (mk1) I can press it a few times in a row without losing so much charge that it has to stop to recharge (battery-dependent, of course), so i'm guessing around the 1/64 mark. Can the higher-model speedlites be programmed to output a certain power from the test-button?

I think it depends what mode you're in. If you're in ETTL, then the flash is calculating the output for you (and varying it accordingly). If you have it in manual mode, then it will fire at whatever power you have the flash set to.

During one of these long exposure, multiple flash popping experiements, I'd suggest keeping the flash set to a relatively low power so that you don't have to wait for it to recycle. Typically speaking, under those conditions, you don't necessarily need anything above 1/8 or 1/16 power anyway. Set it to that kind of power or less, and you could hit the test fire button just about as many times as you wanted within a 5 second exposure and never worry about recycle times.

On my 580 II you have to make sure the C.Fn-07 is set properly. At the "0" (which I think is the defult) the output power for a test fire is 1/32 power. If you change C.Fn-07 to the "1" state, then the flash will fire at full power when test fired. I assume full power would mean it would fire at the power you have it set to, but I do not have time right now to look that up to confirm (I will try latter).

[Dr Croubie]

Well, at any rate, on my 430EXmk1, I turned the flash to Manual, 1/1 Power, hit the test button, and it put out a lot of power. That's what I was aiming for, thanks.
(strange I didn't think of that, but normally I set the power from my 7D on slave mode for macro/product shots, and ettl for the rare occasions it's on-camera.)

[jrw]

An alternative to Canon flashes are the Metz units. I have a few of them myself. Less money than Canon, ETTL compatible when Canon version purchased, and more modes of operation. They do have the ability to fire when other flash units go off which was always a good way to get around the limitation of 3 flash groups when using optical wireless mode. For the exposure times I use during portraits, and other indoor shots, there really is no lag time issue, though I'm sure at higher shutter speeds it would become an issue at some point. Haven't felt the need to test this further to see what the limit is.