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Old 16th of June 2010 (Wed)   #16
apersson850
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Default Re: How to sync. 550D to studio flash??????

The camera detects an external flash in the hotshoe, since you put something in there. A piece of correctly shaped cardboard would do the same, since this detection is done mechanically.

Then you try to talk to it, through the camera's menu system, but that's done electronically, and since the camera then expect to find a compatible Canon flash up there (like a 430 EX II), it says your "cardboard" is incompatible or off.
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Old 16th of June 2010 (Wed)   #17
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Default Re: How to sync. 550D to studio flash??????

Quote:
Originally Posted by apersson850 View Post
The camera detects an external flash in the hotshoe, since you put something in there. A piece of correctly shaped cardboard would do the same, since this detection is done mechanically.

Then you try to talk to it, through the camera's menu system, but that's done electronically, and since the camera then expect to find a compatible Canon flash up there (like a 430 EX II), it says your "cardboard" is incompatible or off.
Well explained about the cardboard! So, my original summary is correct then, if the 550D now considers a Kenro trigger to be a 'piece of cardboard', then Canon have introduced restrictions on external flash devices it will recognise on the 550D that do not exist on other models, specifically the 400D and 50D?
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Old 16th of June 2010 (Wed)   #18
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Default Re: How to sync. 550D to studio flash??????

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Originally Posted by BoardingInFive View Post
Thanks for that. So, when I put on the Kenro infrared flash trigger, the internal flash menu's are disabled, as an external flash device is detected, but when I try and access any external flash menu I just get an error screen saying the 'device is not switched on or powered up' (which it is), so I appear to have no accessible external flash settings.
You're never going to get accessible flash controls from your camera with a non-Canon flash or trigger, because the camera cannot possibly know how to control every single unit ever produced - and has no way of controlling it even if it did. The external flash screen controls are intended only for certain compatible Canon flashguns.

However, your Kenro trigger should still work fired from the hotshoe in a fully manual way - same as it would with any other camera. You don't need the external control menus - set your shutter, ISO and aperture to suit the flash exposure and press the shutter button ...the Kenro trigger will operate as the shutter opens.

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Originally Posted by BoardingInFive View Post
I put the Kenro onto a 400D or a 50D and it just fires straight away, hence the confusion.
I'm assuming the Kenro works, in which case the only reason I can think it doesn't fire on the 550D is that you're trying to use it at the same time as Live View?

For some reason on low-end Canon SLRs using live view disables the centre-pin on the flash hotshoe (also the pc socket on cameras that have it). If you want to use flash AND live view, then you will have to use a compatible Canon flashgun, or the pop-up.

Canon cameras from the 40D upwards can get around this by switching off 'silent shooting' in the menus - this then allows the pc socket and hotshoe centre-pin to work as normally during live view, but there's no option to do this currently on anything below a 40D.

There is a bodge which is supposed to get around this - you pop up the onboard flash during live view, which then re-activates the hotshoe centre-pin ...but you need to blank off the pop-up flash AND figure out a way to connect to the centre-pin without putting anything in the hotshoe that operates the switch telling the camera there's something in the hotshoe. I've never tried this, and there's no way of knowing whether this poses any risk to the camera circuitry.

If you're not using live view while trying to use the Kenro (and the Kenro definitely works), then there's something wrong with the electrical connection between camera hotshoe and trigger.

Rob
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Old 16th of June 2010 (Wed)   #19
BoardingInFive
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Default Re: How to sync. 550D to studio flash??????

Quote:
Originally Posted by RobKirkwood View Post
You're never going to get accessible flash controls from your camera with a non-Canon flash or trigger, because the camera cannot possibly know how to control every single unit ever produced - and has no way of controlling it even if it did. The external flash screen controls are intended only for certain compatible Canon flashguns.

However, your Kenro trigger should still work fired from the hotshoe in a fully manual way - same as it would with any other camera. You don't need the external control menus - set your shutter, ISO and aperture to suit the flash exposure and press the shutter button ...the Kenro trigger will operate as the shutter opens.


I'm assuming the Kenro works, in which case the only reason I can think it doesn't fire on the 550D is that you're trying to use it at the same time as Live View?

For some reason on low-end Canon SLRs using live view disables the centre-pin on the flash hotshoe (also the pc socket on cameras that have it). If you want to use flash AND live view, then you will have to use a compatible Canon flashgun, or the pop-up.

Canon cameras from the 40D upwards can get around this by switching off 'silent shooting' in the menus - this then allows the pc socket and hotshoe centre-pin to work as normally during live view, but there's no option to do this currently on anything below a 40D.

There is a bodge which is supposed to get around this - you pop up the onboard flash during live view, which then re-activates the hotshoe centre-pin ...but you need to blank off the pop-up flash AND figure out a way to connect to the centre-pin without putting anything in the hotshoe that operates the switch telling the camera there's something in the hotshoe. I've never tried this, and there's no way of knowing whether this poses any risk to the camera circuitry.

If you're not using live view while trying to use the Kenro (and the Kenro definitely works), then there's something wrong with the electrical connection between camera hotshoe and trigger.

Rob
Rob, I really appreciate your views here, as you're actually re-assuring me I'm not just being stupid, and there may actually be an underlying problem.

I wasn't using LiveView, so there's no need for me to explore further down that route.

The 550D was operating in 'Manual' mode, with a shutter speed of 1/125 aperture f11. I ranged the speed from 1/100 to 1/300 and at no point would the flash trigger. It could be operated manually at any time, so was clearly working, and sprang back to life when put on two other camera bodies, so your theory that there's just an underlying problem in the hotshoe might just be the ticket.
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Old 16th of June 2010 (Wed)   #20
watt100
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Default Re: How to sync. 550D to studio flash??????

Quote:
Originally Posted by RobKirkwood View Post
You're never going to get accessible flash controls from your camera with a non-Canon flash or trigger, because the camera cannot possibly know how to control every single unit ever produced - and has no way of controlling it even if it did. The external flash screen controls are intended only for certain compatible Canon flashguns.
Rob

Quote:
Originally Posted by RobKirkwood View Post
I'm assuming the Kenro works, in which case the only reason I can think it doesn't fire on the 550D is that you're trying to use it at the same time as Live View?
For some reason on low-end Canon SLRs using live view disables the centre-pin on the flash hotshoe (also the pc socket on cameras that have it). If you want to use flash AND live view, then you will have to use a compatible Canon flashgun, or the pop-up.
Rob
not true!
You can use Live view and non-Canon flashes at the same time on the 550D and the 450D models. And you can access flash controls from the camera using non-Canon flashes like the Yongnuo YN465, YN468, etc. I don't know about the flash the OP is using however
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Old 16th of June 2010 (Wed)   #21
RobKirkwood
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Default Re: How to sync. 550D to studio flash??????

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Originally Posted by watt100 View Post
not true!
You can use Live view and non-Canon flashes at the same time on the 550D and the 450D models. And you can access flash controls from the camera using non-Canon flashes like the Yongnuo YN465, YN468, etc. I don't know about the flash the OP is using however
We've never had 550D (or 450D for that matter) so I bow to your greater knowledge .

Our 1000D certainly behaves the way I described, and my info about the broader range of Canon cameras behaving like this came from Chris Breeze at Breeze Systems - there's been a couple of discussions about the live view and flash problem on the breeze-sys forum under photo booth.

But the fact remains that the 550D should be capable of firing the Kenro trigger in normal non-live view use.

Rob
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Last edited by RobKirkwood : 16th of June 2010 (Wed) at 05:30.
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Old 16th of June 2010 (Wed)   #22
RobKirkwood
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Default Re: How to sync. 550D to studio flash??????

Just checked the 550D/T2i manual from Canon USA - page 207 states "a non-Canon flash will not fire during Live View shooting."

...so I take back my bowing!

I presume the Yongnuo flashguns work because they have Canon TTL capabilities and the camera thinks it has a Canon Speedlite installed - which is not the problem we were talking about ...firing a non-TTL flash unit or trigger from the 550D.

Rob
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Old 4th of July 2010 (Sun)   #23
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Default Re: How to sync. 550D to studio flash??????

I felt driven to join this forum and put my five pennyworth in. I'm staggered that so many people can't understand the question. It's nothing to do with shutter speed or Canon made flashes. It happens with my Olympus E510 and my Canon 550D and probably most DSLRs with a roof mounted flash.

Here it is in easy steps as I'm doing it to try and sync a Bowens studio flash remotely.

1. Pop up the flash on the camera, take a picture, it all works.
2. Switch the studio flash on, put a piece of white card in front of the camera flash so it doesn't fire at the subject.
3. Press the shutter, camera flash fires, studio flash fires. However there is no light on the subject.
4. This means the studio flash is firing either well before or well after the shutter. Even at 1/10 sec.
5 Wrong! It takes less than a microsecond for the light from the camera flash to reach the studio flash sensor, so where's it going wrong?

I'll give you the answer!

Just inside the pop up flash on the 550D there is a sensor that regulates the light output. If you just put a piece of white card in front of the flash it will direct so much light into the sensor that it will not give a proper exposure. You need to cover the sensor, a finger will do, put the white card in front of the flash and it will then trigger your external flash correctly. After all, you're on manual, so you control the aperture, but if you have too much flash going into the sensor it will operate some sort of protection to avoid overloading the CMOS. Sorted.

Hope that sounded patronising!
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Old 4th of July 2010 (Sun)   #24
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Default Re: How to sync. 550D to studio flash??????

Quote:
Originally Posted by ash2020 View Post
I felt driven to join this forum and put my five pennyworth in. I'm staggered that so many people can't understand the question. It's nothing to do with shutter speed or Canon made flashes. It happens with my Olympus E510 and my Canon 550D and probably most DSLRs with a roof mounted flash.

Here it is in easy steps as I'm doing it to try and sync a Bowens studio flash remotely.

1. Pop up the flash on the camera, take a picture, it all works.
2. Switch the studio flash on, put a piece of white card in front of the camera flash so it doesn't fire at the subject.
3. Press the shutter, camera flash fires, studio flash fires. However there is no light on the subject.
4. This means the studio flash is firing either well before or well after the shutter. Even at 1/10 sec.
5 Wrong! It takes less than a microsecond for the light from the camera flash to reach the studio flash sensor, so where's it going wrong?

I'll give you the answer!

Just inside the pop up flash on the 550D there is a sensor that regulates the light output. If you just put a piece of white card in front of the flash it will direct so much light into the sensor that it will not give a proper exposure. You need to cover the sensor, a finger will do, put the white card in front of the flash and it will then trigger your external flash correctly. After all, you're on manual, so you control the aperture, but if you have too much flash going into the sensor it will operate some sort of protection to avoid overloading the CMOS. Sorted.

Hope that sounded patronizing!
Andrew
That didn't sound too patronizing, but I think you are totally wrong. The OP had a problem with some sort of a trigger mounted in the hotshoe. He changed the trigger and now all is well.

Your tutorial on using the 550D's pop-up flash to fire an optical slave flash seems a little odd to me.

The 550D pop-up flash can only fire ETTL flash. This consists of a preflash for metering and a main flash for lighting the scene. The sensor is in the camera, not in the flash. ETTL always fires a preflash immediately before the shutter opens. This is what can cause an optical slave flash to fire at the wrong time.

I am guessing that putting your finger in front of the 550D's pop-up flash may block the weaker ETTL preflash, and the optical slave flash then fires correctly with the stronger main flash.
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Old 4th of July 2010 (Sun)   #25
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Default Re: How to sync. 550D to studio flash??????

OK Mike, you win. Red face here. I didn't realise that it always fires a pre-flash. That'll be why the results with a slave sync are erratic to say the least, sometimes the pre-flash is blocked, sometimes it isn't.
Thanks
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