Olympus UK E-System User Group
Olympus UK E-System User Group

Join our unique resource for Olympus Four Thirds E-System DSLR and Pen and OM-D Micro Four Thirds photographers. Show your images via our free e-group photo gallery. Please read the e-group.uk.net forum terms and conditions before posting for the first time. Above all, welcome!


Go Back   Olympus UK E-System User Group > Cameras, lenses and system accessories > Accessory talk > Flash

Flash FL-related discussions can be found here.

Reply
 
Thread Tools Display Modes
  #1  
Old 1st June 2008
Graham_of_Rainham's Avatar
Graham_of_Rainham Graham_of_Rainham is online now
Administrator
 
Join Date: Nov 2007
Location: Rainham
Posts: 8,221
Thanks: 647
Thanked 950 Times in 735 Posts
Likes: 2,311
Liked 1,623 Times in 936 Posts
Question Flash triggering

What is the best way to trigger flash units off the camera?

I've seen posted in threads that some slave units will not trigger the FLs as the voltage is to low too run the trigger. I've also heard that some old flash guns can damage the camera if connected to a PC hot shoe adaptor.

Any suggestions please

Graham
__________________
Graham

We often repeat the mistakes we most enjoy...
Reply With Quote
  #2  
Old 1st June 2008
snaarman's Avatar
snaarman snaarman is offline
Full member
 
Join Date: Feb 2008
Location: Baaarkshire UK
Posts: 6,867
Thanks: 502
Thanked 417 Times in 325 Posts
Likes: 492
Liked 1,343 Times in 507 Posts
Re: Flash triggering

FWIW, I have used both my Nikon SB28 and Vivitar 550 FD (99p off ebay!) with my Olympus 8080 and E-400 with no problems. These also both trigger using a light sensing slave from Hama. I knew they were safe to use because I measured the trigger voltages at 4 to 6 volts. No problem there...

However I avoided my another cheap flash units because their trigger voltages measured 85v. Not good for your camera.

So the answer is that there are lots of flash units that may well work, and just as many that might fry an unprotected camera. The only sure way is to measure the voltage between the centre pin and the the earth connection (usually on the side of the bracket where it contacts the camera flash mount bracket) To do this you need a cheap digital Volt Meter (DVM) .. A cheap DVM can be as little as 5 - which might be a smart investment if you want to buy 3rd party flashed of ebay.

Equally, you might be able to afford proper Olympus flashes, you might not be a cheapskate like me :-)

Pete
__________________
Look, I'm an old man. I shouldn't be expected to put up with this.


Pete's photoblog Misleading the public since 2010.
Reply With Quote
  #3  
Old 1st June 2008
Graham_of_Rainham's Avatar
Graham_of_Rainham Graham_of_Rainham is online now
Administrator
 
Join Date: Nov 2007
Location: Rainham
Posts: 8,221
Thanks: 647
Thanked 950 Times in 735 Posts
Likes: 2,311
Liked 1,623 Times in 936 Posts
Re: Flash triggering

Pete,

Now that's what I consider to be a comprehensive reply...
Sincere thanks.

I've got a DVM and will do just as you suggest. Could I please ask what Hama units you have used successfully?

Also anyone else, if you have used a slave unit to successfully trigger a FL50, can you let me know the make/model etc..

Graham
__________________
Graham

We often repeat the mistakes we most enjoy...
Reply With Quote
  #4  
Old 1st June 2008
photonutter's Avatar
photonutter photonutter is offline
Full member
 
Join Date: Nov 2007
Location: St Helens Merseyside
Posts: 270
Thanks: 15
Thanked 7 Times in 6 Posts
Likes: 0
Liked 0 Times in 0 Posts
Re: Flash triggering

I use a light cube, got from jessops. http://www.jessops.com/Store/s9094/0...y=False&comp=n
You use the built in flast to trigger so no problems there.
Reply With Quote
  #5  
Old 1st June 2008
snaarman's Avatar
snaarman snaarman is offline
Full member
 
Join Date: Feb 2008
Location: Baaarkshire UK
Posts: 6,867
Thanks: 502
Thanked 417 Times in 325 Posts
Likes: 492
Liked 1,343 Times in 507 Posts
Re: Flash triggering

Graham

Sorry, I don't recall which Hama it was.. It was a Christmas present and it doesn't have a model number on it.. However, it looks like this...



Pete

PS, in the spirit of this post I shot this image using my E400 and bounced flash from the SB28 :-)
__________________
Look, I'm an old man. I shouldn't be expected to put up with this.


Pete's photoblog Misleading the public since 2010.
Reply With Quote
  #6  
Old 1st June 2008
Graham_of_Rainham's Avatar
Graham_of_Rainham Graham_of_Rainham is online now
Administrator
 
Join Date: Nov 2007
Location: Rainham
Posts: 8,221
Thanks: 647
Thanked 950 Times in 735 Posts
Likes: 2,311
Liked 1,623 Times in 936 Posts
Re: Flash triggering

Pete,

That's brilliant, thanks a lot

FYI Measured the following voltages @ the contacts :-

Olympus F280 - 3.0v
Olympus FL50 - 4.65v
Sunpak 433D - 9.8v
Cobra RS10 - 190v
Olympus PS200 - 280v

So I guess I wont be putting my oldest Oly Flash onto my E-Sys Camera

Regards

Graham
__________________
Graham

We often repeat the mistakes we most enjoy...
Reply With Quote
  #7  
Old 20th July 2008
Naughty Nigel's Avatar
Naughty Nigel Naughty Nigel is offline
Full member
 
Join Date: May 2008
Location: Land of the Prince Bishops
Posts: 10,123
Thanks: 413
Thanked 586 Times in 497 Posts
Likes: 3,491
Liked 2,512 Times in 1,645 Posts
Re: Flash triggering

I may be too late replying, but....

All electronic flashguns charge a large value capacitor to a potential of 300 to 350 or so volts, which is then discharged over a period of a few S through a glass tube containing xenon gas. Indeed, any electronic flashgun (including those in compact cameras) is capable of delivering a fatal electric shock.

The voltage at the flashgun terminals is determined by the triggering circuitry. Older cameras with mechanical flash contacts could safely handle high voltages and currents from simple flashguns without sustaining damage (even though the user was at risk of electrocution). However, modern cameras with solid state flash triggering can only handle low voltages and currents, and may also be sensitive to polarity.

Regarding remote triggering.......
Digital cameras fire their flashguns twice for each exposure.

When the shutter button is pressed, the flashgun fires a short, measured pre-flash to calculate exactly how much flash power is required. This is follwed a few milliseconds later by the main flash. Most remote triggering units are not capable of relaying this information to or from the flashgun, so when the master flash fires its pre-flash, the slave guns fire at full power. Not only does this completely discharge the slave flashguns; it also confuses the exposure system, resulting is severe under-exposure.
__________________
---------------

Naughty Nigel


Difficult is worth doing
Reply With Quote
  #8  
Old 21st July 2008
Invicta's Avatar
Invicta Invicta is offline
Full member
 
Join Date: Nov 2007
Location: Third rock from the sun
Posts: 1,025
Thanks: 67
Thanked 243 Times in 125 Posts
Likes: 19
Liked 83 Times in 48 Posts
Re: Flash triggering

Quote:
Originally Posted by Naughty Nigel View Post
I may be too late replying, but....


Regarding remote triggering.......
Digital cameras fire their flashguns twice for each exposure.

When the shutter button is pressed, the flashgun fires a short, measured pre-flash to calculate exactly how much flash power is required. This is follwed a few milliseconds later by the main flash. Most remote triggering units are not capable of relaying this information to or from the flashgun, so when the master flash fires its pre-flash, the slave guns fire at full power. Not only does this completely discharge the slave flashguns; it also confuses the exposure system, resulting is severe under-exposure.
Interesting info, sorry to jump in but I think this helps explain my experiments with a remote controlled FL50-R when using mirror lock-up on the camera.

When I press the shutter the camera pop-up flash sends a signal out and the remote FL50-R also gives a small flash. (is this FL50-R flash equivalent to the pre-flash?)

When the mirror lock-up time-out is reached then the pop-up flash fires again and the FL50-R now gives its full powered flash.

Mirror lock-up seems to be limited to about 4 seconds as any longer than this and the FL50-R will just fire all on its own after approx 4 seconds.
Reply With Quote
  #9  
Old 21st July 2008
Naughty Nigel's Avatar
Naughty Nigel Naughty Nigel is offline
Full member
 
Join Date: May 2008
Location: Land of the Prince Bishops
Posts: 10,123
Thanks: 413
Thanked 586 Times in 497 Posts
Likes: 3,491
Liked 2,512 Times in 1,645 Posts
Re: Flash triggering

Quote:
Originally Posted by Invicta View Post
Interesting info, sorry to jump in but I think this helps explain my experiments with a remote controlled FL50-R when using mirror lock-up on the camera.

When I press the shutter the camera pop-up flash sends a signal out and the remote FL50-R also gives a small flash. (is this FL50-R flash equivalent to the pre-flash?)

When the mirror lock-up time-out is reached then the pop-up flash fires again and the FL50-R now gives its full powered flash.

Mirror lock-up seems to be limited to about 4 seconds as any longer than this and the FL50-R will just fire all on its own after approx 4 seconds.
I'm not too sure how flash metering would work on an E3. I would assume the first (pre) flash occurs just before the mirror goes up, and the second fires a second or two later, when any mirror vibrations have died down?

I cannot see any problems with this, as long as the subject being captured doesn't change in the intervening period.

On a more conventional camera (like the E1 -which doesn't have Live View), the exposure system cannot work with the mirror locked up, as the light sensors are housed in the pentaprism.
__________________
---------------

Naughty Nigel


Difficult is worth doing
Reply With Quote
  #10  
Old 21st July 2008
Invicta's Avatar
Invicta Invicta is offline
Full member
 
Join Date: Nov 2007
Location: Third rock from the sun
Posts: 1,025
Thanks: 67
Thanked 243 Times in 125 Posts
Likes: 19
Liked 83 Times in 48 Posts
Re: Flash triggering

Quote:
Originally Posted by Naughty Nigel View Post
I'm not too sure how flash metering would work on an E3. I would assume the first (pre) flash occurs just before the mirror goes up, and the second fires a second or two later, when any mirror vibrations have died down?

I cannot see any problems with this, as long as the subject being captured doesn't change in the intervening period.

On a more conventional camera (like the E1 -which doesn't have Live View), the exposure system cannot work with the mirror locked up, as the light sensors are housed in the pentaprism.
Not sure of the E-3 flash metering either but the pre-flash before mirror lock-up would explain what I see happening.

You can set the mirror-lock to a wide range of time intervals I used to use 10 seconds, alas the main flash happens all on its own after 4 seconds so with remote flash you have use a much shorter mirror lock-up time.
Reply With Quote
  #11  
Old 21st July 2008
Naughty Nigel's Avatar
Naughty Nigel Naughty Nigel is offline
Full member
 
Join Date: May 2008
Location: Land of the Prince Bishops
Posts: 10,123
Thanks: 413
Thanked 586 Times in 497 Posts
Likes: 3,491
Liked 2,512 Times in 1,645 Posts
Re: Flash triggering

Quote:
Originally Posted by Invicta View Post
Not sure of the E-3 flash metering either but the pre-flash before mirror lock-up would explain what I see happening.

You can set the mirror-lock to a wide range of time intervals I used to use 10 seconds, alas the main flash happens all on its own after 4 seconds so with remote flash you have use a much shorter mirror lock-up time.
But does it still expose correctly?

TBH, I cannot see the point of mirror lock up with flash (as the flash will freeze any movement), or indeed mirror lock of more than a few seconds.
__________________
---------------

Naughty Nigel


Difficult is worth doing
Reply With Quote
  #12  
Old 21st July 2008
Invicta's Avatar
Invicta Invicta is offline
Full member
 
Join Date: Nov 2007
Location: Third rock from the sun
Posts: 1,025
Thanks: 67
Thanked 243 Times in 125 Posts
Likes: 19
Liked 83 Times in 48 Posts
Re: Flash triggering

Quote:
Originally Posted by Naughty Nigel View Post
But does it still expose correctly?

TBH, I cannot see the point of mirror lock up with flash (as the flash will freeze any movement), or indeed mirror lock of more than a few seconds.
With mirror lock-up it exposes OK if the mirror lock-up is less than four seconds as the signal from the camera pop-up flash causes the main flash to happen at the right time.

If mirror lock-up is say 10 seconds this is what happens

time 0, camera pop-up flash sends signal out, main flash gives pre-flash

time +4 seconds, main flash fires

time +10 seconds camera pop-up flash sends signal, main flash does nothing, picture under exposed.

I am puzzled by this but you have a valid point about the flash freezing any movement.
Reply With Quote
  #13  
Old 22nd July 2008
Naughty Nigel's Avatar
Naughty Nigel Naughty Nigel is offline
Full member
 
Join Date: May 2008
Location: Land of the Prince Bishops
Posts: 10,123
Thanks: 413
Thanked 586 Times in 497 Posts
Likes: 3,491
Liked 2,512 Times in 1,645 Posts
Re: Flash triggering

Quote:
Originally Posted by Invicta View Post
With mirror lock-up it exposes OK if the mirror lock-up is less than four seconds as the signal from the camera pop-up flash causes the main flash to happen at the right time.

If mirror lock-up is say 10 seconds this is what happens

time 0, camera pop-up flash sends signal out, main flash gives pre-flash

time +4 seconds, main flash fires

time +10 seconds camera pop-up flash sends signal, main flash does nothing, picture under exposed.

I am puzzled by this but you have a valid point about the flash freezing any movement.

Indeed. I don't think I have ever used mirror lock up on my E1, although I have used it on other cameras.

The whole idea of mirror lock is to prevent vibration caused by the mirror flapping up and down during long (tripod mounted) exposures.

I would therefore suggest that using mirror lock up with a flashgun is not only unneccessary, but will also slow down the whole picture taking process.
__________________
---------------

Naughty Nigel


Difficult is worth doing
Reply With Quote
Reply

Thread Tools
Display Modes

Posting Rules
You may not post new threads
You may not post replies
You may not post attachments
You may not edit your posts

BB code is On
Smilies are On
[IMG] code is On
HTML code is Off

Forum Jump

Similar Threads
Thread Thread Starter Forum Replies Last Post
Blue Tit - tried with flash... theMusicMan Foto Fair 3 9th April 2008 07:03 AM
Powering flash from the mains? lauriek Flash 8 9th February 2008 12:30 AM
advice on flash sanke Accessory talk 7 20th January 2008 10:35 AM
RC flash video sapper Olympus E-3 1 10th January 2008 10:46 AM
New RC Flash - FL-50R / FL-36R dlinney Flash 2 7th December 2007 11:59 PM


All times are GMT. The time now is 09:36 AM.


The Write Technology Ltd, 2007-2019, All rights reservedAd Management plugin by RedTyger