Hey 365 family!!
I have a strobe flash which can be triggered by any other flash however, when I trigger it with my external flash all photos are underexposed badly.
If I hook up one strobe to my camera via hot shoe to trigger the other strobe everything works fine. The problem is when I trigger them with my external flash. Does anyone know how to fix this problem?
It looks like you use Canon and I'm a Nikon guy, so probably not familiar with the gear you're using.
How does your external flash know to fire? Are you using radio triggers or is it triggered from your hotshoe flash?
If it's the hotshoe, and it's anything like Nikon, then it sends out "preflashes", little bursts of light to tell the external flash what to do.
What happens then is that these preflashes trigger your optical strobe flash prematurely. Then the main external flash fires as directed by these preflashes, but the optical flash has already gone off before your shutter was open.
My external flash is sitting on my camera. The strobe is out in front of the subject. The external flash does not send out the preflashes you talk about. It flashes and at the same time triggers the strobe but for some reason all photos are under exposed.
Yeah, what @agima said -- We need lots more information to figure this out.
Also, what are your camera settings? What shutter speeds are the pictures you've taken so far?
Just throwing this out there: I usually use a 580 EX II as my master, and either a 430 EX II or LP160 as my slaves. Both of the slaves behave completely differently, and it took me a bit to understand how to work them.
In short, the 430 EX II works off of infrared signals from the 580 EX II and requires a bit of configuration to use. It does not have an optical slave mode, which is a total bummer for such an expensive piece of equipment. Was the source of many headaches.
The LP160 can also work off of the infrared signals (I think) but also has a normal optical slave mode, meaning that it will simply be triggered by a flash (or pre-flash, I think -- I'm a bit rusty on the technical details). Regardless, both of these modes are selectable on the body of the flash, so if the flash you're using is anything like this, you probably also have two different slave modes.
So, with that said, give us all the info you can, and I'm sure we can straighten this out for you! :)
@gurry Just a small correction. They dont use infrared to communicate, its the pre-flash that does it. It is just that the receiver looks like an infrared receiver.
@agima I'm curious about this too. I use my little Canon G10 underwater with two Nikonos strobes, by firing the on-camera flash to trigger the strobes working in slave mode (manual, generally 1/16 or 1/4 output). Only problem is, if I have the camera set to front curtain sync it doesn't work, I think because some sort of pre-flash triggers the strobes prematurely. Changing the on-camera flash to rear-curtain sync is a perfectly workable solution for me, but it's not ideal. I'd prefer to know exactly what is happening in this situation...
@dieter The pre flash does not care if you are first or second sync. What are you tring to achieve with the curtain changes and why is changing them a problem.....
Normally it only matters if you are having an exposure longer than the flash.
@dieter Oh I should add that if the slave does not know how to deal with pre flash and it is set to fire on the detection of a flash then the slave will fire prematurely and will not register with the camera. This is a problem when you mix studio strobes with speed lights.
@agima I don't know why it works, but changing to rear curtain fixes the problem completely. First curtain: camera doesn't see the external flash. Second curtain: works perfectly. This is completely irrespective of shutterspeed
@agima hmmm.... see that's what I don't understand. The built-in flash triggers the external flash. How is it possible that the camera can miss the external flash? I just don't get it. The external flash HAS to be triggering prematurely. Since the shutterspeed is much longer than the flash duration the camera isn't missing the flash after the shutter closes. And it can't be missing the flash beforehand if it's triggered by the main burst from the built-in flash. The only remaining possibility that I can see is ... 'some sort of pre-flash'... If you have any other ideas I could test then fire away
BTW, your explanation above fits perfectly: "...if the slave does not know how to deal with pre flash and it is set to fire on the detection of a flash then the slave will fire prematurely and will not register with the camera..."
But you say the built-in flash isn't capable of pre-flash?
@dieter Correct the 7d is the only canon camera that I know of that can use its built in flash as a master. The others do not have this capability. Now having said that I don't know nothing about th G10.
They this... Take a photo in the mirror and see if you can see the built in flash. Do you have options on your camera to control other flashes. Ie master slave type set up
@agima Bingo!! the G10 does a pre-flash exposure check, which must be what triggers the Nikonos strobes. As discussed here switching the flash to manual mode should fix the problem.
But, as I say, switching to rear-curtain sync does the trick in a practical sense anyway.
@agima p.s. thanks for the discussion :) I don't have the camera with me, but will try a shot in the mirror out of curiosity (will try the switching to manual mode too!). I very much doubt it has any options for for controlling other flashes, it's just a compact (a nice one, but still)
After thinking about it more, the LP160 has two settings -- one that ignores the preflash (to use when coupled with a flash that fires a preflash), and one that doesn't (to use when the master has no preflash).
@rayg86 No problem to help you, but indeed please give camera and flash type.
I use a Canon EOS 60D + 580EX II. This week I used hem off the camera, being trigerred by the built-in flash. I know the problems and also how to solve them, but please more details first.
@djepie
I am using very basic equipment, Nothing fancy like you all just yet.
Camera: Canon rebel XTi
Flash: Promaster 7200DF
Strobe: Flashlige 459
When i use promaster flash to trigger the strobe all photos are under exposed but if I take the flash off and use the built in flash everything is fine.... im so lost.
@rayg86 From what I've read, the Promaster 7200 sometimes doesn't fit in the camera's hot shoe very well, which could cause it to miscommunicate with the camera and probably cause incorrect exposures. You might want to make sure it's sitting snug, and all the connectors are touching.
I can't find any information about the "Flashlige 459." Is that the correct name?
When you take a picture, does the Promaster fire? Does the strobe also fire?
Up above, @agima and I asked you a bunch of questions. We'd be more helpful if you can answer them! :)
Tweets ahoy!
Join the Group
Pin With Me
How does your external flash know to fire? Are you using radio triggers or is it triggered from your hotshoe flash?
If it's the hotshoe, and it's anything like Nikon, then it sends out "preflashes", little bursts of light to tell the external flash what to do.
What happens then is that these preflashes trigger your optical strobe flash prematurely. Then the main external flash fires as directed by these preflashes, but the optical flash has already gone off before your shutter was open.
You seem very vague on what you are trying to do. Can you tell me:
what model of speedlights you are using for each of the situation
What channel they are on
What group they are in
Are they firing ETTL or manual
Can you tell me exactly where you are placing the units in relation to each other and the subject. Also can you send me some example photos.
Also, what are your camera settings? What shutter speeds are the pictures you've taken so far?
Just throwing this out there: I usually use a 580 EX II as my master, and either a 430 EX II or LP160 as my slaves. Both of the slaves behave completely differently, and it took me a bit to understand how to work them.
In short, the 430 EX II works off of infrared signals from the 580 EX II and requires a bit of configuration to use. It does not have an optical slave mode, which is a total bummer for such an expensive piece of equipment. Was the source of many headaches.
The LP160 can also work off of the infrared signals (I think) but also has a normal optical slave mode, meaning that it will simply be triggered by a flash (or pre-flash, I think -- I'm a bit rusty on the technical details). Regardless, both of these modes are selectable on the body of the flash, so if the flash you're using is anything like this, you probably also have two different slave modes.
So, with that said, give us all the info you can, and I'm sure we can straighten this out for you! :)
Normally it only matters if you are having an exposure longer than the flash.
BTW, your explanation above fits perfectly: "...if the slave does not know how to deal with pre flash and it is set to fire on the detection of a flash then the slave will fire prematurely and will not register with the camera..."
But you say the built-in flash isn't capable of pre-flash?
They this... Take a photo in the mirror and see if you can see the built in flash. Do you have options on your camera to control other flashes. Ie master slave type set up
But, as I say, switching to rear-curtain sync does the trick in a practical sense anyway.
After thinking about it more, the LP160 has two settings -- one that ignores the preflash (to use when coupled with a flash that fires a preflash), and one that doesn't (to use when the master has no preflash).
Makes sense now :]
I use a Canon EOS 60D + 580EX II. This week I used hem off the camera, being trigerred by the built-in flash. I know the problems and also how to solve them, but please more details first.
I am using very basic equipment, Nothing fancy like you all just yet.
Camera: Canon rebel XTi
Flash: Promaster 7200DF
Strobe: Flashlige 459
When i use promaster flash to trigger the strobe all photos are under exposed but if I take the flash off and use the built in flash everything is fine.... im so lost.
I can't find any information about the "Flashlige 459." Is that the correct name?
When you take a picture, does the Promaster fire? Does the strobe also fire?
Up above, @agima and I asked you a bunch of questions. We'd be more helpful if you can answer them! :)
It is hard to help without answers.