AF-540FGZ in Slave + P-TTL Oddity

WooKstah · 08-21-2012, 06:10 AM

OK, this is a bit of an odd one, but I've recently picked up a 2nd AF-540FGZ to play around more with lighting, and I've just realized that the original flash I bought 2nd hand cannot seem to be put into P-TTL mode when the flash is set as a Wireless Slave; I've only got A and M no matter how hard I try, however the new (to me) flash allows it without an issue. The P-TTL mode appears if the camera isn't in Wireless slave (i.e. Wireless Master, Control, or any of the non-wireless modes), so I'm a bit stumped as to what's going on. I've glanced through the manual a few times, and I can't seem to find anything, and no amount of button mashing seems to resolve the issue.

Any ideas?

**maxfield_photo** · 08-21-2012, 07:58 AM

I think maybe you need to "register" the flash with the camera. With the flash turned off, slide it on the hotshoe, then turn it on, and press the shutter halfway. pTTL should then be available, and you can take the flash off the camera, and put it where you want. Beware though, if the flash goes into hibernation while off camera it may forget that it was in pTTL and the settings that you entered. I don' t know if there is a way to disable this on Pentax flashes other than to use a TTL cord and an off camera adapter. At the very least you'll want to set the longest hibernate time available, and pop off a frame every now and then even if you aren't ready to take the picture.

steve1307 · 08-21-2012, 09:33 AM - **1 Like**

Are you in wireles Slave mode 1 "SL1" (this is the normal one where wireless P-TTL works) or are you in slave mode 2 "SL2" (which is just a manual strobe setting for a basic slave flash).

page 52 of the manual shows how to change it.
Slide the switch on the right up. Press the button marked LIGHT for more than 2 seconds. It will swap from SL1 to SL2 or vice versa.

For P-TTL function in wireless you need SL1.

WooKstah · 08-21-2012, 12:41 PM

Bingo! That was the issue ... not sure how I missed that nugget of information, nor how I managed to get it into that mode to begin with. Many thanks!

Originally posted by steve1307

Are you in wireles Slave mode 1 "SL1" (this is the normal one where wireless P-TTL works) or are you in slave mode 2 "SL2" (which is just a manual strobe setting for a basic slave flash).

page 52 of the manual shows how to change it.
Slide the switch on the right up. Press the button marked LIGHT for more than 2 seconds. It will swap from SL1 to SL2 or vice versa.

For P-TTL function in wireless you need SL1.

08-21-2012, 06:10 AM	#1
WooKstah Forum Member Join Date: Mar 2011 Location: Ottawa, ON Posts: 70	AF-540FGZ in Slave + P-TTL Oddity OK, this is a bit of an odd one, but I've recently picked up a 2nd AF-540FGZ to play around more with lighting, and I've just realized that the original flash I bought 2nd hand cannot seem to be put into P-TTL mode when the flash is set as a Wireless Slave; I've only got A and M no matter how hard I try, however the new (to me) flash allows it without an issue. The P-TTL mode appears if the camera isn't in Wireless slave (i.e. Wireless Master, Control, or any of the non-wireless modes), so I'm a bit stumped as to what's going on. I've glanced through the manual a few times, and I can't seem to find anything, and no amount of button mashing seems to resolve the issue. Any ideas?

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08-21-2012, 07:58 AM	#2
maxfield_photo Site Supporter Join Date: Mar 2011 Location: Cincinnati, OH Posts: 1,216	I think maybe you need to "register" the flash with the camera. With the flash turned off, slide it on the hotshoe, then turn it on, and press the shutter halfway. pTTL should then be available, and you can take the flash off the camera, and put it where you want. Beware though, if the flash goes into hibernation while off camera it may forget that it was in pTTL and the settings that you entered. I don' t know if there is a way to disable this on Pentax flashes other than to use a TTL cord and an off camera adapter. At the very least you'll want to set the longest hibernate time available, and pop off a frame every now and then even if you aren't ready to take the picture.

08-21-2012, 09:33 AM - 1 Like	#3
steve1307 Veteran Member Join Date: Mar 2010 Location: Sydney Photos: Gallery \| Albums Posts: 1,130	Are you in wireles Slave mode 1 "SL1" (this is the normal one where wireless P-TTL works) or are you in slave mode 2 "SL2" (which is just a manual strobe setting for a basic slave flash). page 52 of the manual shows how to change it. Slide the switch on the right up. Press the button marked LIGHT for more than 2 seconds. It will swap from SL1 to SL2 or vice versa. For P-TTL function in wireless you need SL1.

08-21-2012, 12:41 PM	#4
WooKstah Forum Member Join Date: Mar 2011 Location: Ottawa, ON Posts: 70 Original Poster	Bingo! That was the issue ... not sure how I missed that nugget of information, nor how I managed to get it into that mode to begin with. Many thanks! Originally posted by steve1307 Are you in wireles Slave mode 1 "SL1" (this is the normal one where wireless P-TTL works) or are you in slave mode 2 "SL2" (which is just a manual strobe setting for a basic slave flash). page 52 of the manual shows how to change it. Slide the switch on the right up. Press the button marked LIGHT for more than 2 seconds. It will swap from SL1 to SL2 or vice versa. For P-TTL function in wireless you need SL1.