Wireless flash & second curtain sync

Twarp · 02-10-2012, 07:05 AM

The K-x flash menu displays only one wireless flash option, the most right one. If I want to use my AF-360FGZ remotely (without cable=wireless), how does the camera know it has to sync the flash-unit with the second curtain with the flashunit set to that position? Channel number, slave option and proper zoom manually set, everything functions properly in standard mode.

Or does second curtain sync only work when the external flash is connected through a wire or mounted on the hot shoe?

jase036 · 02-10-2012, 07:14 AM

As far as I know, second curtain sync will not work when using wireless mode...

Twarp · 02-10-2012, 07:23 AM

Now I'm thinking about this, with flash mounted on the camera, what happens when the setting of the camera is different from the setting on the flash-unit? E.g.
- camera=standard, flash= second curtain
- camera=second curtain, flash=standard
- and mixes with the other settings

Does one overrule the other?

Anvh · 02-10-2012, 07:36 AM

Setting in the camera is for the pop-up flash, only the flash exposure balance does have an effect.
So if you want second curtain with a seperate flash that you put on the camera you need to use the menu in the flash to set it up.

Twarp · 02-10-2012, 07:49 AM

@Anvh: that makes sense because you normally cannot use the popup flash with something mounted on the hotshoe. Except for the situation when you use the popup flash combined with a hotshoe wire connection, so both flashes are active at the same time with mixed up settings. I should have mentioned this in the first place but since I do not have these cable/hotshoe connector combi, it is purely a hypothetical problem. I will for know just forget about the little setup I had in mind when starting this thread...

majan · 02-10-2012, 08:03 AM

My solution for wireless flash and 2nd curtain sync is:
- One flash on the camera (eg. af540fgz). I am using this flash in pttl and 2nd curtain sync
- DIY flash trigger to ignore preflash and fire on real flash. Trigger is connected to RF-602TX.
- Any number of RF-602RXs with manual flash

The flash trigger is mounted on af540 head using velcro and is connected via pc-sync with rf-602tx...it looks maybe a little crazy, but IT WORKS!
My plan is to disassemble the transmitter and put it into one box with flash trigger.

Twarp · 02-10-2012, 08:29 AM

This sounds like a more experienced strobist speaking...
Now you mention more than one external flash, I should use a second AF_xxx flash. Set the shoe-mounted one to second curtain flash and to Master, then the second wireless one will fire on the main flash regardles of its setting because it is a slave. In P-TTL it ignores the preflash anyway.
Bummer, I have only one external flash

This problem shouldn't exist if the popup flash has more wireless options...

majan · 02-10-2012, 08:55 AM

I think, that your setup will not work. In wireless (master/slave) mode, you cannot set 2nd curtain with pentax flashes...your master/slave will flash always on 1st curtain - if I remeber correctly.

There are flashes with built in trigger to ignore preflash. I have one yongnuo 560 and it works...But if I mixed it with pentax flash booth as wireless slave and control them from on camera (540fgz as master), the result is that only yongnuo is visible in exposure...The pentax slave fires, but not on the right time

Metz flashes ca do wireless and 2nd curtain, but I don't have them

The working solution I found with my setup was described above. And I think it gives me a pretty good results. Manual flashes for atmosphere (especially in large rooms) and on camera pttl for fill.

Twarp · 02-10-2012, 03:16 PM

Did some quick testing and indeed it doesn't fire on the second curtain when controlled wirelessly. That only works when the Pentax flash is shoe-mounted and set accordingly.
However, it appears in my test that the preflash at the start of the sequence is as bright as the main flash when the shutter closes. The popup flash has the same behaviour, which seems a bit erratic to me. I would expect the preflash also at the end.

I'm not sure if I'm into this more elaborate setups but I'll keep it in mind. Perhaps an additional Metz for starters...

Anvh · 02-10-2012, 04:21 PM

The preflash is purely for the metering and sincec the lightmeter is in the viewfinder-housing the mirror needs to be down so it can only meter a scene before a photo is taken.

jase036 · 02-10-2012, 07:35 PM

Like I said at the beginning, unless you use something like majan's DIY setup, Pentax's wireless mode does not allow trailing curtain sync, not even with Metz flashes (I use Metz). Since it relies on pre-flash to comunicate metering info, it would be absurd to use a flash to indicate 2nd curtain as the shutter would be open. I would like to see something like the Radiopopper or PW wireless system for Pentax allowing P-TTL and trailing curtain sync.

Twarp · 02-11-2012, 01:47 AM

Ok guys, thanks for thinking and arguing along

For me the more advanced flash options just became available with my new flash-unit. On second thought it is clear that the preflash can only work with a closed shutter. I guess I need to follow a diagram or flow chart to decide on probable settings and circumvent traps each time.

Another option for Pentax could be to re-introduce the good old "real" TTL mode like on the LX and Super A. Am I correct to suspect that P-TTL is a step down from TTL? Only drawback is that everybody needs new equipment. The only other flash-unit I own (the AF280T, with TTL) works like a charm in A-mode on the K-x. It just misses the advanced options like zoom, wireless etc. and has no clue what P-TTL is. Just as my K-x isn't setup for TTL (talking about mismatch!). Also here proper thinking (not always capable in my case

) is necessary to apply proper settings...

Anvh · 02-11-2012, 04:07 AM

With TTL they meter the light off the film but a Sensor is something very different as far as i know they couldn't do it reliably.

Twarp · 02-11-2012, 04:20 AM

The results I had with TTL on film were consistently satisfactory, not taking human error into account. Perhaps you are right that it doesn't work right in all circumstances but the method of measuring flash during exposure is theoretically more sound than measuring before the exposure when changes can still occur.
I guess the main reason for abandoning the system is cost. Flashing twice is cheaper than incorporating extra lenses and sensors in the camera.

majan · 02-11-2012, 05:33 AM

Originally posted by jase036

I would like to see something like the Radiopopper or PW wireless system for Pentax allowing P-TTL and trailing curtain sync

Me too. It is too difficult to decode the communication between body and flash? Or there is canon/nikon dominance and for pentax it wold be non profitable....?
I am thinking about trying to decode some communication. Especially the 2nd curtain sync. With a little luck, maybe will be able to simulate the flash presence with microchip on hotshoe and firing the trigger (rf602tx) on 2nd curtain sync. This would be enough for me

PTTL with radio signal would be nice, but too difficult, imho.

02-10-2012, 07:05 AM	#1
Twarp Forum Member Join Date: Jan 2012 Photos: Gallery \| Albums Posts: 77	Wireless flash & second curtain sync The K-x flash menu displays only one wireless flash option, the most right one. If I want to use my AF-360FGZ remotely (without cable=wireless), how does the camera know it has to sync the flash-unit with the second curtain with the flashunit set to that position? Channel number, slave option and proper zoom manually set, everything functions properly in standard mode. Or does second curtain sync only work when the external flash is connected through a wire or mounted on the hot shoe?

02-11-2012, 01:47 AM	#12
Twarp Forum Member Join Date: Jan 2012 Photos: Gallery \| Albums Posts: 77 Original Poster	Ok guys, thanks for thinking and arguing along For me the more advanced flash options just became available with my new flash-unit. On second thought it is clear that the preflash can only work with a closed shutter. I guess I need to follow a diagram or flow chart to decide on probable settings and circumvent traps each time. Another option for Pentax could be to re-introduce the good old "real" TTL mode like on the LX and Super A. Am I correct to suspect that P-TTL is a step down from TTL? Only drawback is that everybody needs new equipment. The only other flash-unit I own (the AF280T, with TTL) works like a charm in A-mode on the K-x. It just misses the advanced options like zoom, wireless etc. and has no clue what P-TTL is. Just as my K-x isn't setup for TTL (talking about mismatch!). Also here proper thinking (not always capable in my case ) is necessary to apply proper settings... Last edited by Twarp; 02-11-2012 at 02:10 AM.

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02-10-2012, 07:14 AM	#2
jase036 Senior Member Join Date: Mar 2010 Location: Calgary, Alberta Photos: Gallery Posts: 170	As far as I know, second curtain sync will not work when using wireless mode...

02-10-2012, 07:23 AM	#3
Twarp Forum Member Join Date: Jan 2012 Photos: Gallery \| Albums Posts: 77 Original Poster	Now I'm thinking about this, with flash mounted on the camera, what happens when the setting of the camera is different from the setting on the flash-unit? E.g. - camera=standard, flash= second curtain - camera=second curtain, flash=standard - and mixes with the other settings Does one overrule the other?

02-10-2012, 07:36 AM	#4
Anvh Veteran Member Join Date: Sep 2011 Posts: 4,616	Setting in the camera is for the pop-up flash, only the flash exposure balance does have an effect. So if you want second curtain with a seperate flash that you put on the camera you need to use the menu in the flash to set it up.

02-10-2012, 07:49 AM	#5
Twarp Forum Member Join Date: Jan 2012 Photos: Gallery \| Albums Posts: 77 Original Poster	@Anvh: that makes sense because you normally cannot use the popup flash with something mounted on the hotshoe. Except for the situation when you use the popup flash combined with a hotshoe wire connection, so both flashes are active at the same time with mixed up settings. I should have mentioned this in the first place but since I do not have these cable/hotshoe connector combi, it is purely a hypothetical problem. I will for know just forget about the little setup I had in mind when starting this thread...

02-10-2012, 08:03 AM	#6
majan New Member Join Date: Oct 2010 Posts: 3	My solution for wireless flash and 2nd curtain sync is: - One flash on the camera (eg. af540fgz). I am using this flash in pttl and 2nd curtain sync - DIY flash trigger to ignore preflash and fire on real flash. Trigger is connected to RF-602TX. - Any number of RF-602RXs with manual flash The flash trigger is mounted on af540 head using velcro and is connected via pc-sync with rf-602tx...it looks maybe a little crazy, but IT WORKS! My plan is to disassemble the transmitter and put it into one box with flash trigger.

02-10-2012, 08:29 AM	#7
Twarp Forum Member Join Date: Jan 2012 Photos: Gallery \| Albums Posts: 77 Original Poster	This sounds like a more experienced strobist speaking... Now you mention more than one external flash, I should use a second AF_xxx flash. Set the shoe-mounted one to second curtain flash and to Master, then the second wireless one will fire on the main flash regardles of its setting because it is a slave. In P-TTL it ignores the preflash anyway. Bummer, I have only one external flash This problem shouldn't exist if the popup flash has more wireless options...

02-10-2012, 08:55 AM	#8
majan New Member Join Date: Oct 2010 Posts: 3	I think, that your setup will not work. In wireless (master/slave) mode, you cannot set 2nd curtain with pentax flashes...your master/slave will flash always on 1st curtain - if I remeber correctly. There are flashes with built in trigger to ignore preflash. I have one yongnuo 560 and it works...But if I mixed it with pentax flash booth as wireless slave and control them from on camera (540fgz as master), the result is that only yongnuo is visible in exposure...The pentax slave fires, but not on the right time Metz flashes ca do wireless and 2nd curtain, but I don't have them The working solution I found with my setup was described above. And I think it gives me a pretty good results. Manual flashes for atmosphere (especially in large rooms) and on camera pttl for fill.

02-10-2012, 03:16 PM	#9
Twarp Forum Member Join Date: Jan 2012 Photos: Gallery \| Albums Posts: 77 Original Poster	Did some quick testing and indeed it doesn't fire on the second curtain when controlled wirelessly. That only works when the Pentax flash is shoe-mounted and set accordingly. However, it appears in my test that the preflash at the start of the sequence is as bright as the main flash when the shutter closes. The popup flash has the same behaviour, which seems a bit erratic to me. I would expect the preflash also at the end. I'm not sure if I'm into this more elaborate setups but I'll keep it in mind. Perhaps an additional Metz for starters...

02-10-2012, 04:21 PM	#10
Anvh Veteran Member Join Date: Sep 2011 Posts: 4,616	The preflash is purely for the metering and sincec the lightmeter is in the viewfinder-housing the mirror needs to be down so it can only meter a scene before a photo is taken.

02-10-2012, 07:35 PM	#11
jase036 Senior Member Join Date: Mar 2010 Location: Calgary, Alberta Photos: Gallery Posts: 170	Like I said at the beginning, unless you use something like majan's DIY setup, Pentax's wireless mode does not allow trailing curtain sync, not even with Metz flashes (I use Metz). Since it relies on pre-flash to comunicate metering info, it would be absurd to use a flash to indicate 2nd curtain as the shutter would be open. I would like to see something like the Radiopopper or PW wireless system for Pentax allowing P-TTL and trailing curtain sync.

02-11-2012, 04:07 AM	#13
Anvh Veteran Member Join Date: Sep 2011 Posts: 4,616	With TTL they meter the light off the film but a Sensor is something very different as far as i know they couldn't do it reliably.

02-11-2012, 04:20 AM	#14
Twarp Forum Member Join Date: Jan 2012 Photos: Gallery \| Albums Posts: 77 Original Poster	The results I had with TTL on film were consistently satisfactory, not taking human error into account. Perhaps you are right that it doesn't work right in all circumstances but the method of measuring flash during exposure is theoretically more sound than measuring before the exposure when changes can still occur. I guess the main reason for abandoning the system is cost. Flashing twice is cheaper than incorporating extra lenses and sensors in the camera.

02-11-2012, 05:33 AM	#15
majan New Member Join Date: Oct 2010 Posts: 3	Originally posted by jase036 I would like to see something like the Radiopopper or PW wireless system for Pentax allowing P-TTL and trailing curtain sync Me too. It is too difficult to decode the communication between body and flash? Or there is canon/nikon dominance and for pentax it wold be non profitable....? I am thinking about trying to decode some communication. Especially the 2nd curtain sync. With a little luck, maybe will be able to simulate the flash presence with microchip on hotshoe and firing the trigger (rf602tx) on 2nd curtain sync. This would be enough for me PTTL with radio signal would be nice, but too difficult, imho.