Off-camera flash sync question

[Paladin3]

I have a brand new Vivitar DF340ZC TTL flash that doesn't communicate with the camera correctly. After testing it appears the flash is firing before the shutter is open. I've tried slow shutter speeds and second curtain sync but no luck. If I go into dark room, put the camera on bulb and fire the flash by hand while the shutter is open I get a decent picture (of course I only get full power flash, no TTL.) I know it's not the camera because the flash has done the same thing on several cameras.

Vivitar tech support explained that the company had been sold and some very crappy units were sent to market at one point. Rather than try to fix the POS, he sent me a DF383 for free and all was good in the world.

I still have the first "broken" flash that works fine other than the sync issue. I was thinking about buying an optical slave for it to use in the studio. Since the light triggering the unit is already in sync there shouldn't be any issues, right?

 

[corkyg]

Sounds like a defective unit. Brand new? Still under warranty? Sounds like Vivitar stood behind it. I would put it in my monthly discard box for pickup by Vietnam Vets. I would not invest anything further in it.

 

[Gooberlx2]

It could be worth trying out if optical triggers aren't too expensive.

However if the issue was a communication problem/failure at the hotshoe, then you might experience exactly the same thing with the optical trigger.

 

[angry hampster]

Triggers may solve the problem.

My experience with Vivitar flashes has been less than positive. I had a flash melt on me during a professional shoot:

It was replaced with a Yongnuo 560, which I love.

 

[twistedlogic]

You could disable the two pins on the bottom of the flash and then try it on-camera, bypassing TTL.

If it is still not in sync an optical trigger would have the same results.

 

[Numenorean]

Triggers may solve the problem.

My experience with Vivitar flashes has been less than positive. I had a flash melt on me during a professional shoot:

It was replaced with a Yongnuo 560, which I love.

Vivitar & Yongnuo + "professional shoot" = oxymoron.

 

[angry hampster]

Vivitar & Yongnuo + "professional shoot" = oxymoron.

No reason to use my 580 as a slave.

 

[Madwand1]

Since the light triggering the unit is already in sync there shouldn't be any issues, right?

Not necessarily, but you might get lucky. If the issue is with the TTL logic and the slave doesn't have that, then you might bypass the issue that way. Similarly, you could trying taping over all but the center contact on the flash or your camera, and try it that way (with the flash on "auto", not TTL). If that doesn't work, odds are that it won't work as a slave.

However I agree that as it's a known defective unit, it might not be worth taking further chances with it. Flashes have high voltages, and some have been known to fry modern cameras on occasion.

 

[RobDickinson]

Are you sure the DF340ZC is WIRELESS ettl?

I dont think it is?

Which , if you put it in optical trigger mode and have the camera/master firingin ETTL wireless mode then the preflash will trigger the DF340ZCbefore the shutter opens.

if you want to fire it as a dumb off camera flash with your onboard you will have to disable ettl on the camera.

 

[iGas]

Triggers may solve the problem.

My experience with Vivitar flashes has been less than positive. I had a flash melt on me during a professional shoot:

It was replaced with a Yongnuo 560, which I love.

I have 2 Vivitar 285HV for roughly 20 years and they both still function perfectly. They do get very hot after extended usage, however my Canon 430EZ just about as hot if I cycles it quickly as well.

 

[iGas]

Vivitar & Yongnuo + "professional shoot" = oxymoron.

Perhaps he might be interested in my 2400W power pack and studio lighting kit (180lbs) that have been collecting dust on my shelf for over a decade.

 

[Paladin3]

You could disable the two pins on the bottom of the flash and then try it on-camera, bypassing TTL.

If it is still not in sync an optical trigger would have the same results.

The first thing I tried was taping over everything but the center pin and the flash wouldn't fire at all. Nor would it fire with only two of the four non-center pins covered.

I'm really not trying to get the flash to work on camera. Vivitar has already upgraded me to a free DF-293 to replace it (about a year ago) so anything I can get this flash to do is a free bonus.

It's not in sync because it's firing before the shutter is open. Triggering it with an optical slave would force it to wait until the shutter is open because the master flash triggering it already did. The flash and camera would not be communicating and I'm not trying to achieve eTTL at all. Just a blast of light for a kicker or hair light in the studio. I can move the flash around to adjust it's output.

I figure for the price of a $10 optical slave from eBay I can salvage what is otherwise junk. Or maybe I'll just take it apart and begin my foray into strobe repair...or make a homemade stun gun.

 

[Paladin3]

Vivitar & Yongnuo + "professional shoot" = oxymoron.

Vivitar 283/285 were the only flashes I used for probably the first 10 years of my newspaper career. Everyone was shooting manual cameras like the Canon F1n or Nikon F3 or FM2n. There was nothing else around as well built, compact, full-featured and inexpensive as those Vivitars. The vari-power module with the fractional settings was way cool for it's time, as was the off-camera cord with a socket for the vari-power built into the hot shoe end.

283/285s recycled like crazy with a battery pack, but you did melt the occasional 285HV simply because it could fire full power manual blasts faster than hell. Any plastic strobe will do the same thing if you force it to kick out too much light and heat too fast. That's why I always carried several extra with me on shoots.

We've got it easier now with AF, eTTL and cameras that do much of the exposure setting faster than we can. For shooting a fast breaking news event, I would much rather have a modern DSLR on AF and program with an eTTL strobe than go back to the all manual days when we missed shots because we couldn't change settings fast enough.

 

[SecurityTheatre]

Triggering it with an optical slave would force it to wait until the shutter is open because the master flash triggering it already did.

Keep in mind, for this to work, the flash on the camera has to be in FULL MANUAL mode.

Using ANY sort of TTL on the main flash will make the optical slaves trigger early. This is because the TTL works by firing a "pre-flash" in order to meter the scene, and then firing a second flash to actually take the picture. Optical slaves will trigger on the first and miss the shot.

In some systems (Nikon), there can be up to 3 (or even 4) pre-flashes if the wireless triggering system is turned on. They happen quite quickly, so you normally don't notice, but try turning on all 4 zones in a Nikon flash and you will visually see all the pre-flashing going on.

ST