K20 hot shoe versus pc-terminal synching

Ben_Edict · 05-17-2010, 12:22 PM

Today my set of remote flash triggers arrived. I bought the RF-602 transmitter and several receivers and my initial impression is quite good. Before that I used RF-604s, which always made problems with ignoring the synch impulse etc. - or so I thought.

I tried the RF-602 in the hot shoe of my K20 and with one of my studio flashes. Every shot was triggered, but sometimes a second flash was triggered immediately, without pressing the shutter button.

Than I realized, that, though the flash fired reliably, the images turned out black. SO I lowered my sanch times down to 1/60, but the turnout wasn't better. The ofdd shot was okay, but about 2 in 3 shots were black. The very same issue, I had with the RF-604...

Suddenly I though, I should try the PC-terminal on the K20, because when I use a synch cord, everything is fine with my flashes and the K20. So I used a short synch cord to connect the RF-602 transmitter to the K20 AND NOW every shot was fine, though not at the shortest synch time of 1/180. I need to go down to 1/125 to have a fully illuminated image - but that's mostly fine.

What I do not quite get is, what the hot shoe makes differently, than the PC-terminal? The PC-temrinal, though not useable with the 1/180s is nevertheless fully reliable, wheras the remote trigger in the hot shoe is working intermittently at best. Or is it just my K200, that behaves faulty? With my hot shoe flash guns, everything works fine in any mode (camera on Av or on M, flash in P-TTL, A or M modes), it's just those remote triggers that behave strangely.

Anybody has the same problems or has a solution/suggestion?

Ben

Wheatfield · 05-17-2010, 04:57 PM

Is it possible that the PC terminal has a more direct connection to the flash trigger? If the signal to the hot shoe has to go through the processor, that would slow things down a bit.
FWIW, I've been using those horribly overpriced Pocket Lizards for a year now, and have not had a single misfire or shot lost to poor synchronization.

alohadave · 05-17-2010, 05:37 PM

RF-602's have issues with Pentax cameras. There is a big thread here somewhere that details the issues that some people have had with them.

Russell-Evans · 05-18-2010, 03:27 AM - **1 Like**

Originally posted by Ben_Edict

I tried the RF-602 in the hot shoe of my K20 and with one of my studio flashes. Every shot was triggered, but sometimes a second flash was triggered immediately, without pressing the shutter button.

You must have the Nikon version. The second flash is triggered by the metering turning itself off. You set the metering to a longer time, 30 second maximum, to lessen this.

Originally posted by Ben_Edict

Than I realized, that, though the flash fired reliably, the images turned out black. SO I lowered my sanch times down to 1/60, but the turnout wasn't better. The ofdd shot was okay, but about 2 in 3 shots were black. The very same issue, I had with the RF-604...

This happens with the Nikon version. If you look closely at the green LED on the trigger when metering is active, you will notice the flicker. I think if you hit the shutter when the green LED is lit, everything works. If you hit the shutter during a flicker, you hit the delay and the shutter is closed on the camera.

Originally posted by Ben_Edict

Suddenly I though, I should try the PC-terminal on the K20, because when I use a synch cord, everything is fine with my flashes and the K20. So I used a short synch cord to connect the RF-602 transmitter to the K20 AND NOW every shot was fine, though not at the shortest synch time of 1/180. I need to go down to 1/125 to have a fully illuminated image - but that's mostly fine.

If you set the camera to 1/3 stops you can get 1/160 sync.

Originally posted by Ben_Edict

What I do not quite get is, what the hot shoe makes differently, than the PC-terminal?

There is a second pin active on the flash triggers. This is needed as the receiver is supposed to wake up the remote flashes when needed. The second pin is what activates receivers and thus the flashes putting them into an "I'm ready" mode. . This second pin isn't active on the sync cord, but then you hit the shutter speed limit as the receiver isn't in its ready mode. At one time I thought I was getting 1/180 with the Canon version of the trigger, but it is the same as the Nikon version, 1/160 is as good as it gets unless you modify the button on the trigger so that it is always at half press.

I've heard on the Canon and Nikon systems all this works very well. On Pentax cameras however, the triggers don't live up to their potential. I personally don't think they should be sold as advertised for Pentax cameras. They really don't work on Pentax cameras correctly.

Thank you
Russell

Last edited by Russell-Evans; 05-18-2010 at 03:34 AM.

05-17-2010, 12:22 PM	#1
Ben_Edict Veteran Member Join Date: Jul 2007 Location: SouthWest "Regio" Photos: Albums Posts: 3,309	K20 hot shoe versus pc-terminal synching Today my set of remote flash triggers arrived. I bought the RF-602 transmitter and several receivers and my initial impression is quite good. Before that I used RF-604s, which always made problems with ignoring the synch impulse etc. - or so I thought. I tried the RF-602 in the hot shoe of my K20 and with one of my studio flashes. Every shot was triggered, but sometimes a second flash was triggered immediately, without pressing the shutter button. Than I realized, that, though the flash fired reliably, the images turned out black. SO I lowered my sanch times down to 1/60, but the turnout wasn't better. The ofdd shot was okay, but about 2 in 3 shots were black. The very same issue, I had with the RF-604... Suddenly I though, I should try the PC-terminal on the K20, because when I use a synch cord, everything is fine with my flashes and the K20. So I used a short synch cord to connect the RF-602 transmitter to the K20 AND NOW every shot was fine, though not at the shortest synch time of 1/180. I need to go down to 1/125 to have a fully illuminated image - but that's mostly fine. What I do not quite get is, what the hot shoe makes differently, than the PC-terminal? The PC-temrinal, though not useable with the 1/180s is nevertheless fully reliable, wheras the remote trigger in the hot shoe is working intermittently at best. Or is it just my K200, that behaves faulty? With my hot shoe flash guns, everything works fine in any mode (camera on Av or on M, flash in P-TTL, A or M modes), it's just those remote triggers that behave strangely. Anybody has the same problems or has a solution/suggestion? Ben

Similar Threads
Thread	Thread Starter	Forum	Replies	Last Post
Hot Shoe Covers	Alfisti	Pentax DSLR Discussion	29	06-10-2010 03:19 PM
Hot shoe question	Rondec	Pentax DSLR Discussion	9	11-03-2009 10:21 PM
Wein Safe-Sync Hot Shoe to Hot Shoe	Iowa Tom	Pentax DSLR Discussion	1	09-12-2009 09:20 PM
Right side hot-shoe - why is it gone?	Prognathous	Film SLRs and Compact Film Cameras	9	06-22-2009 08:14 AM

05-17-2010, 04:57 PM	#2
Wheatfield Moderator Join Date: Apr 2008 Location: The wheatfields of Canada Posts: 15,981	Is it possible that the PC terminal has a more direct connection to the flash trigger? If the signal to the hot shoe has to go through the processor, that would slow things down a bit. FWIW, I've been using those horribly overpriced Pocket Lizards for a year now, and have not had a single misfire or shot lost to poor synchronization.

05-17-2010, 05:37 PM	#3
alohadave Veteran Member Join Date: Jan 2008 Location: Quincy, MA Photos: Gallery \| Albums Posts: 2,024	RF-602's have issues with Pentax cameras. There is a big thread here somewhere that details the issues that some people have had with them.

05-18-2010, 03:27 AM - 1 Like	#4
Russell-Evans Veteran Member Join Date: Nov 2007 Posts: 1,553	Originally posted by Ben_Edict I tried the RF-602 in the hot shoe of my K20 and with one of my studio flashes. Every shot was triggered, but sometimes a second flash was triggered immediately, without pressing the shutter button. You must have the Nikon version. The second flash is triggered by the metering turning itself off. You set the metering to a longer time, 30 second maximum, to lessen this. Originally posted by Ben_Edict Than I realized, that, though the flash fired reliably, the images turned out black. SO I lowered my sanch times down to 1/60, but the turnout wasn't better. The ofdd shot was okay, but about 2 in 3 shots were black. The very same issue, I had with the RF-604... This happens with the Nikon version. If you look closely at the green LED on the trigger when metering is active, you will notice the flicker. I think if you hit the shutter when the green LED is lit, everything works. If you hit the shutter during a flicker, you hit the delay and the shutter is closed on the camera. Originally posted by Ben_Edict Suddenly I though, I should try the PC-terminal on the K20, because when I use a synch cord, everything is fine with my flashes and the K20. So I used a short synch cord to connect the RF-602 transmitter to the K20 AND NOW every shot was fine, though not at the shortest synch time of 1/180. I need to go down to 1/125 to have a fully illuminated image - but that's mostly fine. If you set the camera to 1/3 stops you can get 1/160 sync. Originally posted by Ben_Edict What I do not quite get is, what the hot shoe makes differently, than the PC-terminal? There is a second pin active on the flash triggers. This is needed as the receiver is supposed to wake up the remote flashes when needed. The second pin is what activates receivers and thus the flashes putting them into an "I'm ready" mode. . This second pin isn't active on the sync cord, but then you hit the shutter speed limit as the receiver isn't in its ready mode. At one time I thought I was getting 1/180 with the Canon version of the trigger, but it is the same as the Nikon version, 1/160 is as good as it gets unless you modify the button on the trigger so that it is always at half press. I've heard on the Canon and Nikon systems all this works very well. On Pentax cameras however, the triggers don't live up to their potential. I personally don't think they should be sold as advertised for Pentax cameras. They really don't work on Pentax cameras correctly. Thank you Russell Last edited by Russell-Evans; 05-18-2010 at 03:34 AM.