I cannot stop my 7D internal flash firing when set up for wireless with 430 EX II.

[BryanShaw1]

I have followed the set up instructions on the camera, with the middle icon set in the wireless func. setting.

The test flash is OK with a pre-flash from the camera, and a successful firing of the speedlite.

However, when taking a picture, the 7D internal flash fires at the same time as the speedlite.

Can you help please?

[jrhoffman75]

 "contributing" means the on-cmaera flash will also fire at power and provide additional light if the 430 isn't powerful enough versus just firing a low power trigger flash.

Are you getting overexposed flash because the on-camera is adding its light to the 430?

[BryanShaw1]

John,

Totally over exposed - the internal is firing at full strength.

I just need to find a way of turning off the internal - which all the Canon literature says is possible.

As you can see in the Canon guide I enclosed earlier - the first two options state '......with or without the built in flash firing'.

Later on in the guide (not forwarded to you) the middle option on the 7D's wireless function screen (the single speedlite icon),

the text says 'Trigger off-camera speedlites only' and goes on to say 'choose this option if you want the built-in flash to trigger off-camera speedlites without the built-in flash contributing to the exposure'

It is so frustrating knowing the option is available but not being able to find out how!

Regards,

Bryan.

[jrhoffman75]

Hi Bryan - Since you are experiencing overexposure I am thinking perhaps there's a setting off on the 430; I would think if it was set for TTL it should control its output and if it is getting light from the camera it should reduce its output. It doesn't know where the light is coming from, only the intensity.

I tried this with my T5i, which has the same function.

1. With the 430EXIII off I set the camera to the icon that only has external flash and took a photo. It was underexposed on the T5i. With normal flash use exposure was OK, meaning that flash power has been reduced.

2. Then I took a photo with with 430EXIII turned on and it was properly exposed as well.

Setting on 430EXIII was ETTL (lightning bolt) SLAVE in the top of the window.

Try Step 1 with your camera and see what happends.

[RobertTheFat]

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@BryanShaw1 wrote:

John,

Totally over exposed - the internal is firing at full strength.

I just need to find a way of turning off the internal - which all the Canon literature says is possible.

As you can see in the Canon guide I enclosed earlier - the first two options state '......with or without the built in flash firing'.

Later on in the guide (not forwarded to you) the middle option on the 7D's wireless function screen (the single speedlite icon),

the text says 'Trigger off-camera speedlites only' and goes on to say 'choose this option if you want the built-in flash to trigger off-camera speedlites without the built-in flash contributing to the exposure'

It is so frustrating knowing the option is available but not being able to find out how!

Regards,

Bryan.

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Are you sure it's the internal, and not the external, that's firing at full strength? The 7D is an ETTL camera and is not compatible with TTL. If your external flash is set to TTL, it will fire at full strength. It will obey signals from the camera only if it's set to ETTL.

[TCampbell]

If you set the on-camera flash to "disable" but it is acting as an E-TTL master, you will still see the flash fire, but it will fire just fractionally BEFORE the shutter opens.  It will not contribute light to the shot.

This can be very confusing because you will actually see the flash fire and think that it's not really disabled.  If the menu says it's disabled... then it's not really firing when the shutter is open... it's firing just prior to the shutter open and it's telling the off-camera flash when to fire and how much power to use.  

The off-camera flash waits a fraction of a second while the camera opens the shutter and THEN fires the strobe.

But this all happens so quickly that you'd think the flashes fired just once and at all at the same time (they didn't).

[RobertTheFat]

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@TCampbell wrote:

If you set the on-camera flash to "disable" but it is acting as an E-TTL master, you will still see the flash fire, but it will fire just fractionally BEFORE the shutter opens.  It will not contribute light to the shot.

This can be very confusing because you will actually see the flash fire and think that it's not really disabled.  If the menu says it's disabled... then it's not really firing when the shutter is open... it's firing just prior to the shutter open and it's telling the off-camera flash when to fire and how much power to use.  

The off-camera flash waits a fraction of a second while the camera opens the shutter and THEN fires the strobe.

But this all happens so quickly that you'd think the flashes fired just once and at all at the same time (they didn't).

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But that scenario doesn't fit the reported facts. The OP tells us that the pictures are badly overexposed. The pre-flash wouldn't cause that.

[kvbarkley]

Except that Canon has some weasel words that the pre-flash may indeed contribute to the exposure in some conditions.

[jrhoffman75]

ETTL measures light hitting sensor, so it shouldn't care where the light is coming from.

[BryanShaw1]

Many thanks for all the posts, however, has anyone actually tried to replicate the problem to give a definitive answer if it is possible to fire the 430EX without effecting exposure from the internal flash?

[jrhoffman75]

Yes. See my Message 13 above.