My 70D does not record the off camera flash. It works fine on board. Can't figure out the problem.

[joechan]

My 70D doesn't record the off camera flash, a 580II but will work on board. I can't figure the problem.

[jrhoffman75]

If I interpret you question correctly are you saying the camera doesn't activate an off camera flash?

check in your manual. There is a setting you need to activate. 

Something similar to this. 

[joechan]

The flash fires on and off camera. But the sensor/camera does not record the light when the flash is off camera.

[jrhoffman75]

So, if you turn flash off the camera will record a properly exposed image, but when you turn flash on no image recorded?

If you put flash on camera same subject exposes properly with flash?

[joechan]

Thanks for finding out my problem. If I use the onboard flash or speedlight on the camera, the images record correctly. But when I take the speedlight off camera and trigger remotely, the light does not record even the the flash fires.

[diverhank]

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@joechan wrote:

Thanks for finding out my problem. If I use the onboard flash or speedlight on the camera, the images record correctly. But when I take the speedlight off camera and trigger remotely, the light does not record even the the flash fires.

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Can you elaborate what on camera mode you are setting for the flash? Did you set the flash on E TT L? It is possible that you might have the flash set to a manual setting that is too dark for the aperture speed and Iso setting for your camera therefore you cannot see it?

also I assume that you are using the 70d flash trigger and not some other external trigger?

[joechan]

I'm using pocket wizards plus ii for remote. I reset all flash settings. Speedlight is ETTL and set to slave off camera. When the speedlight is off camera, everything fires but just not light recorded to the camera. Speedlight on camera is fine. I kicked up the ISO to 1200, f/2.0 1/30th without any change.

[diverhank]

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@joechan wrote:

I'm using pocket wizards plus ii for remote. I reset all flash settings. Speedlight is ETTL and set to slave off camera. When the speedlight is off camera, everything fires but just not light recorded to the camera. Speedlight on camera is fine. I kicked up the ISO to 1200, f/2.0 1/30th without any change.

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Eureka!  Pocket wizards do not transmit TTL information. It just sets off the flash.  For this kind of triggering, you have to use manual for your speedlight.  Set your speed light to manual (try 1/16 power to start).  On camera, adjust your ISO and aperture so that it's really dark (use liveview for easy tell) then shoot off the flash.  You should see the effect of the flash easy enough.  If you still don't see the effect of the flash, increase the flash power.

If you want, I can give you more info on other methods of flash triggering with full ETTL info...for now please try and report back.  Good luck.

[joechan]

I was excited to think that a solution was found, but this didn't work. The puzzle is that camera will record the LIGHT on the subject when the flash is onboard but not when off camera even though the flash fires. Why would the sensor not record the light regardless of where the source?

[diverhank]

Did you set the flash to Manual?  I don't use Pocket Wizard so I'm not certain but I don't think you need to set your flash to slave either.   Just normal, Manual mode.   You mentioned you had it on ETTL...the pocket wizard sets off the flash and in ETTL mode, the flash sends a burst of light so that the camera can measure the light through the lens (TTL).  Now the flash waits for the camera to send back the info on how much to set off the flash.  Since the Pocket Wizard cannot send this info, my guess is the flash did not even fire the second flash, which is the flash light that the camera uses for exposure...Hopefully this makes sense to you?

So get the flash off ETTL and slave mode and try again.  Oh, change the flash setting on the camera to manual also.  You can't use ETTL with your setup.

By the way no puzzle 🙂 -  when the flash is onboard, there is no problem communicating the ETTL info between the camera and the flash so everything works fine.  The problem is your Pocket Wizard limitation.  It's a dumb trigger.  The reason Pocket Wizards is so popular with the Pros is because it works reliably, every time and the most pros use manual everything anyways so dumb but reliable trigger is a plus.

I must have set a record for editing and reediting on this post... :).  By the way with your 70D and 580EXII, you don't really need pocket wizards to fire your flash remotely.  The 70D has a built-in remote flash control that works beautifully with the 580EXII.  The control is optical (bursts of light) so not as good as the pocket wizards especially for outdoor work.  In return, you will have full ETTL functionality.  I made a video on youtube that shows this...I use the 7DII and the 600EX-RT flash but the instructions are almost exactly the same for your camera/flash.

Here's the link: https://www.youtube.com/watch?v=qwKsXjGRXUg