ebay trigger problem...

fallen_mathi

fallen_mathi

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hey all...
Having been bitten by the strobist bug, like many others, I invested in a couple of old flashguns, some ebay triggers, and have made verious softboxes/lightstands/snoots, etc etc... all is good... except... my triggers seem to miss-fire 90% of the time.:crying:
by this i mean, they fire like they should, but the camera doesnt pick it up, so i presume, theyre firing just after the 160/second shutter speed...
now i presume that this is not a regular problem? as if it was why are alot of people using them? so is there anything i can do about it?
(for further information, there being ctr-301p, shot on a 40d, - all the batteries have been replaced with fully charged new ones.)

thanks!
nathan :)
 
Can only suggest that you slow down the shutter until they work.

A quick google suggests that the 40d may only sync at 1/60 in some circumstances
p106 in the manual

Using Non- Canon Flash units

Sync Speed

The camera can synchronize with compact, non-canon flash units at 1/250 sec. Or slower shutter speeds. With large studio flash, the sync speed is1/60 sec. Or slower. Be sure to test the flash unit beforehand to make sure it synchronizes with the camera properly”
Click to expand...
 
They should sync up to 1/200th - mine drove me crazy - wouldn't fire when they should have, and did fire when I didn't want them to - had to get rid of them after only a couple of weeks and replace them with Skyports...
 
Yeah, i've had the same problem. Sync speed ok, flash when they should but black screen :shrug: 90% is alot though, i suppose at there worst i had a problem 1 in every 15-20 shots. I think mine got worse the more shots i took but they haven't messed me about for a while. They can go off for no reason ( as has been mentioned ) but i need to do a test to see if that is down to mobile phones in the room or not. Hope you get to the bottom of your problem (y)
 
hey, thanks for all the quick advice :) can always relly on tp :D

il do a test with them at lower speeds to see if the hit rate is any better,

&

a 430ez and a 420ez

cheers!

nathan
 
I'll chip in with a maybe. Both the 420 and the 430 are known to emit interference at the same frequency as the eBay triggers use (but PW's use a different frequency). The ebay triggers use the same frequency as garage Door remotes in the UK, so that also can be a problem.

To remove suspicion from the flashes themselves, try a different make (like a Nikon) if you can borrow one.

Also try different channels.

Many owners of Canon flashes also say using a cable to distance the trigger from the flash works.

Wonder why I went down the Nikon route ... Oops, don't open that can of worms.
 
oli said:
Derek,

your cactus V4's are superior to those CTR's I think? I have those V4's and could sync all day at 1/250
Click to expand...

I know, but some people just get lucky with them... unfortunately I wasn't one of them... probably not a bad thing in the long run, but not cheap in the long run either! :D
 
cheers everyone! :) right i think i can get hold of another flash from a friend, so il give it a try :D thanks all
 
right... so i tried them with a SB-28... and they worked fine...

so i know the triggers are ok

i know my flashes are ok

but the two dont seem to like each other :(:(

now im not technical genius... so i cant see how i can fix anything, which seems to leave two options - new flashes, or new triggers...

are proper-non ebay triggers such as skyports and pocketwizards actually going to work/be reliable, worth the large price tag?
 
The problem is with your flashes, Canon speedlites are notoriously "noisy". I know Pocke Wizard have developed a "fix" for their new ttl triggers to allow them to work with the Canon flashes, a seach of the Strobist group on Flickr might unearth a fix for yours.
 
resurrecting an old thread here....

...but I'm also having the same problem that you're describing with my ebay crapsters.

Sometimes they don't fire at all, other times there must be a delay in firing as I get the black screen.
I'm using Bowens flash heads, so I'm pretty sure it's not a problem with the flash.
Sometimes I have to rotate the hotshoe trigger back to front and it will start working again...but the wireless range is about 50cm.
This has happened on a lot of photoshoots recently. It's costly, and embarrasing.

Think I've learnt my lesson not to buy cheap tat.

Going to have to rush to Calumet first thing tomorrow morning before the next shoot.
The Calumet ones (http://www.calumetphoto.co.uk/item/CF0051/) also look on the cheap side. But at least I have someone to blame when it stops working
 
Well, I went to Calumet in rush hour this morning to pick up the receiver and transmitter in time for todays shoots.

Got back home and I had a faulty receiver....brilliant.
Called Calumet, and they said it's a known problem!!!???
Well if it's a known problem, then how about a product recall instead of selling faulty units!!??
So had to use the old receiver, half the photos didn't come out due to flash not firing...

I know this post is of no use to anyone, but I felt the need to have a rant
 
djs said:
Well, I went to Calumet in rush hour this morning to pick up the receiver and transmitter in time for todays shoots.

Got back home and I had a faulty receiver....brilliant.
Called Calumet, and they said it's a known problem!!!???
Well if it's a known problem, then how about a product recall instead of selling faulty units!!??
So had to use the old receiver, half the photos didn't come out due to flash not firing...

I know this post is of no use to anyone, but I felt the need to have a rant
Click to expand...

Perhaps what they mean is the quality control is poor and they're unreliable.

I bought a set of YN RF-602's and one of them had a dodgy on switch, although TBF it worked fine. FITP replaced it for me, and I bought a spare just in case cos they are so flippin cheap.

I've not needed it and for about 2,000 exposures over a few sessions they have worked flawlessly. Very happy with them. Very neat design too. I'm now going to sell my regular Pocket Wizards because they don't do anything I want that the Yongnuos cannot do, and are incompatible.
 
A radio trigger will always introduce a bit of a delay - it doen't matter if they are cheapo Cactus types or the most expensive Pocket Wizards, etc.

Because of this, you will need to use a slower speed than the fastest sync. speed which would work from a wired connection.

If you units are mis-firing rather than late firing, do a Google search on modifying the transmitter with an external aerial. It makes a big improvement.


Steve.
 
Steve Smith said:
A radio trigger will always introduce a bit of a delay - it doen't matter if they are cheapo Cactus types or the most expensive Pocket Wizards, etc.

Because of this, you will need to use a slower speed than the fastest sync. speed which would work from a wired connection.

If you units are mis-firing rather than late firing, do a Google search on modifying the transmitter with an external aerial. It makes a big improvement.


Steve.
Click to expand...

Steve, there is effectively no delay with Pocket Wizards. They use fast processors. Their new E-TTL system even has Hypersync which allows you to fine tune the x-sync to individual cameras, and actually increase the marked speed - 1/250sec goes up to 1/400sec or something like that.

My Yongnuo RF-602 (fresh batteries) will sync at 1/250sec on my 40D at low flash output when the flash duration is very short, but at full power with my 580EX (flash duration 1/833sec) there is slight shading. Same thing happens with my Elinchrom studio heads which are similar duration. At 1/200sec it is clear at all times - no need to go as low as the 1/125sec that is often talked about with (other) cheap triggers.
 
HoppyUK said:
Steve, there is effectively no delay with Pocket Wizards. They use fast processors. Their new E-TTL system even has Hypersync which allows you to fine tune the x-sync to individual cameras, and actually increase the marked speed - 1/250sec goes up to 1/400sec or something like that.
Click to expand...

There will always be some delay. THe Pocket Wizards may minimise as much as is possible.

I can't see how a radio trigger can increase the maximum flash sync. shutter speed as that is a function of the shutter itself and is determined by the time the shutter curtains are fully open.


Steve.
 
Steve Smith said:
There will always be some delay. THe Pocket Wizards may minimise as much as is possible.

I can't see how a radio trigger can increase the maximum flash sync. shutter speed as that is a function of the shutter itself and is determined by the time the shutter curtains are fully open.


Steve.
Click to expand...

I didn't believe it either Steve, but it works by taking up the few microseconds of tolerance that exists with regular x-sync timing.

Basically there is a window when the shutter is fully open and the flash can be fired, and it stays open for a tiny amount of time before the second shutter curtain begins to cover the sensor.

Hypersync times the firing of the flash so it goes off at the last possible microsecond, and this allows cameras like the 40/50D to raise their 1/250sec to 1/400sec, and Canon 1-Series cameras to manage 1/500sec.

Rob Galbraith on the subject here, with pics http://www.robgalbraith.com/bins/multi_page.asp?cid=7-9884-9903-9906
 
HoppyUK said:
I didn't believe it either Steve, but it works by taking up the few microseconds of tolerance that exists with regular x-sync timing.

Basically there is a window when the shutter is fully open and the flash can be fired, and it stays open for a tiny amount of time before the second shutter curtain begins to cover the sensor.
Click to expand...

I'm still not convinced. The options are a direct wired link which fires the flash as soon as the contacts (or triac) close or a radio link which sends a code as soon as the contacts are closed which is then decoded by the receiver which fires the flash.

There is no way that the radio link can fire the flash earlier than a direct link.

Also, the flash sync speed is always the fastest speed for which the curtains are fully open. e.g. for 1/250, first curtain opens fully then second curtain starts to close. If you go up a speed, the second curtain will start to close before the first curtain has fully opened. Go to a fast speed like 1/1000 and they will more or less move together exposing a small slit of light to the sensor or film.

This HyperSync mode is most useful when you're trying to minimize ambient light and maximize strobe efficiency at the same time. Prior to HyperSync, this task was most easily accomplished by running a wire between camera and strobe, because the delay associated with any wireless flash trigger meant switching to a slower shutter speed to avoid a black band invading the base of the frame. By signaling the flash to fire a bit ahead of when the camera normally would on its own, HyperSync allows for a sync speed that is both higher than previous wireless trigger devices and higher than a wired connection too.
Click to expand...

Whilst I agree that by optimising the fire time you could get a sync speed which is better than other wireless systems, I can't see how you could better the sync speed which you achieve with a wire as you are still limited by the shutter fully open time.




Steve.
 
Steve Smith said:
I'm still not convinced...
Click to expand...

LOL Steve. But you have to believe the evidence of your own eyes! According to your functional analysis, it cannot work, I agree - so it must work differently. It works off the first-curtain trigger pulse, plus an appropriate delay.

There are a number of other clues as to why this might be so, such as second-curtain sync only available via E-TTL and not available through the camera's PC sync socket.
 
HoppyUK said:
LOL Steve. But you have to believe the evidence of your own eyes! According to your functional analysis, it cannot work, I agree - so it must work differently. It works off the first-curtain trigger pulse, plus an appropriate delay.
Click to expand...

Yes, but if you can make it sync. at a faster shutter speed with a radio, then you could make it work with a wire.... and the manufacturer would then claim a faster shutter speed.

You cannot sync. faster than the fastest shutter speed which has a complete opening of the shutter curtains. The radio or wired part of this is irrelevant.


Steve.
 
HoppyUK said:
LOL Steve. But you have to believe the evidence of your own eyes! According to your functional analysis, it cannot work, I agree - so it must work differently. It works off the first-curtain trigger pulse, plus an appropriate delay.
Click to expand...

Yes, but if you can make it sync. at a faster shutter speed with a radio, then you could make it work with a wire.... and the manufacturer would then claim a faster shutter speed.

You cannot sync. faster than the fastest shutter speed which has a complete opening of the shutter curtains. The radio or wired part of this is irrelevant.

EDIT: The only thing which can be happening here is a scenario such as: The manufacturer knows that it will just about sync. at 1/400 but just to be safe, they put 1/250 in the manual. Someone then manages to tweak it so they can get a faster speed. In reality though, it's not a faster speed than the fastest, shutter full open speed, it's just that they have found the actual fastest sync. speed rather than the stated speed...... and it could still be done with just a wired connection!


Steve.
 
Steve Smith said:
Yes, but if you can make it sync. at a faster shutter speed with a radio, then you could make it work with a wire.... and the manufacturer would then claim a faster shutter speed.

You cannot sync. faster than the fastest shutter speed which has a complete opening of the shutter curtains. The radio or wired part of this is irrelevant.


Steve.
Click to expand...

I agree the radio bit is irrelevant. And Canon could make this feature available without any help from Pocket Wizard if they wanted to, but they are just being prudent with their tolerances.

TBH I think it's a marginal feature in practise and I suspect it won't give any meaningful benefit with longer duration flashes - like my 580EX which is quite long at 1/833sec on full power. There can be naff all 'tolerance' with that combination.

We got on to this when you were talking about radio triggers introducing a delay, and that's kind of a moot point with the PW Hypersync feature. Yes, radio has got to introduce a delay; my experience is that with regular non E-TTL Pocket Wizards the delay is short enough to be insignificant, and even with cheaper RF-602 Yongnuos it is very slight, no more than a third of a stop. Some other 'ebay' triggers, which I have not used, are clearly much worse in this area, especially with low batteries.

Just read your edit:

Steve Smith said:
EDIT: The only thing which can be happening here is a scenario such as: The manufacturer knows that it will just about sync. at 1/400 but just to be safe, they put 1/250 in the manual. Someone then manages to tweak it so they can get a faster speed. In reality though, it's not a faster speed than the fastest, shutter full open speed, it's just that they have found the actual fastest sync. speed rather than the stated speed...... and it could still be done with just a wired connection!
Click to expand...

Yes! (y)

(Sounds very like a faster x-sync speed to me :thinking: :LOL: )
 
HoppyUK said:
Canon could make this feature available without any help from Pocket Wizard if they wanted to, but they are just being prudent with their tolerances.
Click to expand...

I think that's exactly what it is. Canon have set their maximum sync. speed with a bit of a margin. The person in your link has exploited that margin to get a faster speed. With a different camera he may get it even faster or equally, he may get it slower - approaching Canon's stated speed.


Steve.
 
Thinking about this a little more, the way Canon works, it is not really second-curtain sync, more like first-curtain plus a pre-determined delay.

For this to work reliably, you must have a very accurate and consistent shutter. A long time ago I used to spend a lot of time testing various shutters for accuracy and some were hopeless, varying in speed generally and in evenness of coverage across the frame. Horizontal running cloth shutters were often pretty bad.

If this was the case today, then with Canon's modus operanti, you would either get the flash going off too early resulting in ambient light trials being partly in front of the flash image, or too late with the second curtain appearing in shot.

Clever, finely engineered technology I guess.
 
I have read the link but something is not clear to me. Does the transmitter communicate with the camera and get it to send its trigger signal early or is there an early fire function in one of the camera's menus? It can't use the standard trigger timing unless it has some sort of short range look into the future type sensor!


Steve.
 
I read about how they work a while back steve, and I think what it does is piggy back off the camera-flash communications by firing before the camera tells it to, so it fires a milisecond before the curtain starts moving then the radio delay brings the timing to be right, which is why the increase is vvv slight
 
david1701 said:
I read about how they work a while back steve, and I think what it does is piggy back off the camera-flash communications by firing before the camera tells it to
Click to expand...

That's the bit I'm not sure about. How can it possibly fire before the camera tells it to?

In order to fire early, the camera would have to be set to send an early trigger. Unless the transmitter is fitted with a crystal ball!


Steve.
 
Steve Smith said:
I have read the link but something is not clear to me. Does the transmitter communicate with the camera and get it to send its trigger signal early or is there an early fire function in one of the camera's menus? It can't use the standard trigger timing unless it has some sort of short range look into the future type sensor!


Steve.
Click to expand...

Why can't it use the standard trigger timing? I think it probably does, although I it could use any fixed reference point within the operational sequence because it knows exactly how long each function takes - mirror rising, first curtain starting, shutter speed, first curtain finishing, flash timing window now open for a known period, second curtain starting etc.

My guess as to what happens - and this is mostly my own hypothethis through a process of elimination - is that in second-curtain sync mode, the flash knows to ignore the first timing pulse and waits for a second signal generated by the camera (the flash doesn't know the exact timings of different camera models) which is sent through the E-TTL pins. This would explain why second-curtain sync is not available by wireless E-TTL and only via hard wire on camera, as for remote firing it would have to go by a visible light command mid-way through the exposure (or at best the semi-IR light from an ST-E2 master). It could be done by radio though.
 
HoppyUK said:
Why can't it use the standard trigger timing?
Click to expand...

Because the flash is firing before the standard trigger timing.

Think of it in simple terms. If the flash is connected straight to the camera, it will fire as soon as the camera shorts out the sync. connection.

Now put a radio link in place of the wired connection. The camera is still shorting out the same contacts when the shutter fires and the flash is still using the same contacts to fire.

A hypothetical perfect radio transmitter with no delay would fire the flash at the same time as a wired connection would. What would normally be the trigger to fire the flash is now a trigger to start the transmitter.

The radio transmitter cannot think "that camera is going to fire the shutter in about a millisecond, I think I will fire the flash now"

Instead it would need either an early signal from the sync. connection or possibly an early trigger from one of the other signal pins on the hotshoe.


Steve.
 
You've lost me here Steve. And clearly things are not working the way you appear to be suggesting, so it must be some other way. I have no trouble with any aspect of the way I've described things. Nothing is firing ahead of when the camera tells it to :thinking:

Think of it not perhaps as second-curtain sync, and more as first-curtain sync with a pre-determined delay, with the final firing signal sent through the E-TTL contacts at the appropriate moment. As I described earlier.

The way that modern cameras work, with a known series of accurately calculated delays in the chain of events, once the timing sequence is started there is no reason why the flash could not be fired at any time after the instant the shutter button is pressed, or at any other time throughout an exposure of any duration. Or the end of next week if needs be. So why not just before the second curtain begins to travel?
 
HoppyUK said:
The way that modern cameras work, with a known series of accurately calculated delays in the chain of events
Click to expand...

Except it doesn't. A new camera will work at maximum sync. speed with one of my old Vivitar 285 flashes. With a film camera it fires as soon as the flash contacts in the camera close. With a modern DSLR it will fire as soon as whatever it uses (triac) closes. No delay involved and a full exposed frame in either case.

HoppyUK said:
there is no reason why the flash could not be fired at any time after the instant the shutter button is pressed, or at any other time throughout an exposure of any duration. Or the end of next week if needs be. So why not just before the second curtain begins to travel?
Click to expand...

That is my point. The flash could fire at any time after the shutter is fired - but not before.



Steve.
 
I have found quite a bit of confusion about this after doing a search. It would appear to be a Canon only thing so I think it must use another signal apart from the sync. terminal to get an advance trigger. Probably from one of the additional hotshoe pins.

If it worked from the ordinary sync. contact, it would be offered for every camera.

It would appear to only go up to 1/500. Higher than that and it changes to high speed focal plane mode which is a power wasting multi-flash method. 1/500 is only a stop faster than the Canon's stated 1/250 sync. speed. I suspect that the Canon shutter just about manages to be fully open at 1/250 but Canon decided to play safe and specify 1/250.

My search found a post by one person who said that he saw a slight dark edge at 1/500 so I think that backs up this theory.


Steve.
 
Steve Smith said:
Except it doesn't. A new camera will work at maximum sync. speed with one of my old Vivitar 285 flashes. With a film camera it fires as soon as the flash contacts in the camera close. With a modern DSLR it will fire as soon as whatever it uses (triac) closes. No delay involved and a full exposed frame in either case.
Click to expand...

Except that it does! Your next post appear to acknowldge this.

That is my point. The flash could fire at any time after the shutter is fired - but not before.
Click to expand...

Using the pre-determined timing method I have outlined, the flash could fire at any time after the first moment the shutter release is pressed. Which is obviously before the mirror even starts to move, let alone the first and then second shutter curtains. This is the only rationale that allows the Canon system to work the way it does.

Steve Smith said:
I have found quite a bit of confusion about this after doing a search. It would appear to be a Canon only thing so I think it must use another signal apart from the sync. terminal to get an advance trigger. Probably from one of the additional hotshoe pins.
Click to expand...

Isn't this what I've been saying all along? :thinking: I think Nikon works differently and I have a hazy recollection that this is patent related, something to do with a Minolta patent they acquired rights to years ago. In which case, probably every other manufacturer has to adpot a similar method of working (excepting Minolta/Sony).

It would appear to only go up to 1/500. Higher than that and it changes to high speed focal plane mode which is a power wasting multi-flash method. 1/500 is only a stop faster than the Canon's stated 1/250 sync. speed. I suspect that the Canon shutter just about manages to be fully open at 1/250 but Canon decided to play safe and specify 1/250.
Click to expand...

1/250 typo? 'Only' a stop is worth a heck of a lot in some situations, for the rest of us it's not such a big deal since HSS works so well at higher speeds anyway, but in the battle of the specs, every little helps.

Much of the advantage of a high 'natural' x-sync speed is negated by the introduction of high-speed-sync on every top end flash gun. Sure it wastes some power, but if you have enough power to start with it is still very workable and gives fully syncronised flash up to max shutter speed, ie 1/8000sec or even higher.

Canon automatically switches over to HSS mode whenever the nominal x-sync speed is exceeded, ie 1/200sec, 1/250sec, 1/300sec depending on the model.
 
This might help and explain why it works with Canon and Ettl.

Ettl works by doing a micro-flash immediately before the main flash and calculating the main flash required from the micro flash. For this to work the shutter must be open at the micro flash stage. This pre-flash time could be added to the main flash maximum sync speed to give a faster sync speed if you could 'trap' the pre-flash trigger. I suspect this is what PW are doing.

What this means is that the shutter is actually fully open for longer than the stated maximum sync time (it has to be for the pre-flash to work) and that by using this pre-flash time as well as the maximum actual sync time you could get a faster apparent sync speed. This would be Canon Ettl specific and would use one (or a combination) of the other pins to sense the micro flash trigger signal.

Only a theory on my part but I cannot see any other way that would work and is Canon Ettl specific.

John
 
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