# YN565EXII flash - TTL as S2 slave?



## mwr (Mar 27, 2017)

I have a YN565EXII (Canon model) and also have a Sony RX100 III. I'd like to use that flash as a TTL slave to the Sony's pop-up flash. The manual for my YN565EXII says it can use TTL mode as a slave using S2. However, when I set S2 slave, the mode switches to M (Manual) and I can't get it to go to TTL. Does anyone know about this?


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## FotosbyMike (Mar 27, 2017)

I am pretty sure this will not work, if I am reading it right, this is because TTL data is not the same between camera brands.

The only way the Sony will fire the YN 565 is on the Slave mode looking for another flash to fire(Sony popup) and this is going to be manual flash.


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## astroNikon (Mar 27, 2017)

(1) you have a *SONY *camera.
(2) you have a *CANON* compatible flash

Maybe see if you can get a *SONY compatible flash* instead.

For comparison, that CANON compatible flash won't work on a Nikon except in Manual Mode.


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## Derrel (Mar 27, 2017)

Sony and Canon and Nikon all use different TTL protocols for metering and regualting TTL flash output. I think for this you'd need to use NON-TTL protocol to control the flash output. This is why the system is switching to Manual mode.

In many cases, TTL control over the output of flashes is overrated, in my opinion. Manually-set flash levels are steady, repeatable, and consistent, and can be evaluated by the shooter, and exposures set in relation to the flash output, or the other way around, with the flashes adjusted up or down to get them in accord with a desired f/stop setting and shutter speed.


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## WayneF (Mar 27, 2017)

mwr said:


> I have a YN565EXII (Canon model) and also have a Sony RX100 III. I'd like to use that flash as a TTL slave to the Sony's pop-up flash. The manual for my YN565EXII says it can use TTL mode as a slave using S2. However, when I set S2 slave, the mode switches to M (Manual) and I can't get it to go to TTL. Does anyone know about this?




It absolutely does Not say S2 can do TTL flash.  It says the S2 slave mode can be triggered by a TTL flash.

S1 and S2 slave modes are manual flash mode only.  S1 can be triggered from a Manual flash, and S2 can be triggered (in Manual mode) by a TTL flash.

Because...

TTL flashes (including inexpensive compact digitals) do a preflash, so the TTL can be metered first.

If you try to trigger an optical slave (like S1 mode) from a TTL flash, the preflash will trigger it before the shutter opens, so that it is 100% ineffective, expended before the shutter opens.  Plus, this slave flash at the same time as the TTL preflash surely totally confuses the TTL flash metering, so that it will then fire too weakly to be useful to the photo.

S2 mode is the same optical slave mode (manual flash only), but S2 knows to ignore the first TTL preflash (i.e., will wait for the final flash), so that it can be triggered from a TTL flash.  This is so that simple cameras without a manual flash mode can use their digital flash (with preflash) to trigger the manual mode optical flash. That's what S2 slave mode is.

However, with a more sophisticated camera, you can simply use S1 mode and trigger it from manual flash.  Then the triggering camera flash can be set to very low manual power, which will still trigger the slave, but without interfering with your picture lighting.


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