Studio Flash Sync w/ K-R + Voltage Query

helhar · 11-12-2011, 08:26 AM

Hi,

I'd love some info on using my camera with studio lights. I recently purchased a K-R (my first DSLR), which has performed nicely, but I was unable to get it to sync to a Bowens monolight.

I was using an inexpensive (and unreliable) wireless flash trigger, but even when the flash fired, it wasn't in sync. The camera didn't seem to recognize the light system. (I've successfully used this light and trigger with a Canon G-9) Unfortunately, I didn't have enough time to work through every combination of camera settings.

I have strobes at home, and was going to try to find a workable combination of settings, using a sync cable running from the hot shoe. When I did some research, I read that I can fry the camera by using a system with high voltage.

Question 1: What are the camera settings necessary to use a K-R with studio strobes?

Question 2: Is it safe to use the K-R with a sync cable? I have a small Porta-Flash system and an old Ascorlight (Berkey?) 800 ws power pack and heads (my preferred system). I have no clue how to determine the voltage they put out.

Many thanks.
Heller

mannesty · 11-12-2011, 08:42 AM

I'm not an experienced studio flash user, but I do use multiple flashes off-camera using radio triggers.

#1 You must keep your shutter speed on or slower than 1/180th sec as that is the fastest synch speed that Pentax cameras are capable of using so far.

#2 Yes you can use a synch cable. Check the trigger voltage of your flash units. Any modern unit should be OK and will probably have a synch voltage of around 5V.

#3 Check the fastest shutter speed that your radio triggers can work at and whether they are compatible with your camera/flash combination.

#4 You will almost certainly need to use a flash meter to achieve a correct exposure, and set your camera to manual exposure mode.

As a rule of thumb, try ISO 100, 1/125th sec, f11, no EV or flash compensation. See what results you get.

Wheatfield · 11-12-2011, 08:53 AM

With some of the less expensive triggers, you have to drop the shutter speed well below sync because of electronic delays.
I haven't used Bowens units, but I did find with norman that I had to reverse the polarity of the contacts to allow the flash to fire with Pentax. The easiest way to do this is cut the sync cable and put a male and femal mains plug (2 prong extension cord ends) onto the wires so that you can reverse the leads.
We had to do this so that I could use my cameras in the studio. Nikon was fine, Pentax is backwards.
If the camera has a PC outlet, you should be fine with plugging into a studio light, but if you are using a shoe mount adapter, it's best to use a Safe-Sync of some sort to isolate the camera from the flash.

sterretje · 11-12-2011, 11:36 AM

Originally posted by Wheatfield

With some of the less expensive triggers, you have to drop the shutter speed well below sync because of electronic delays.
I haven't used Bowens units, but I did find with norman that I had to reverse the polarity of the contacts to allow the flash to fire with Pentax. The easiest way to do this is cut the sync cable and put a male and femal mains plug (2 prong extension cord ends) onto the wires so that you can reverse the leads.
We had to do this so that I could use my cameras in the studio. Nikon was fine, Pentax is backwards.
If the camera has a PC outlet, you should be fine with plugging into a studio light, but if you are using a shoe mount adapter, it's best to use a Safe-Sync of some sort to isolate the camera from the flash.

Your creativity sounds like that of a friend of mine who did that long ago with a head phone. Worked well till he one day by accident put it in the wall outlet

Wheatfield · 11-12-2011, 08:29 PM

Originally posted by sterretje

Your creativity sounds like that of a friend of mine who did that long ago with a head phone. Worked well till he one day by accident put it in the wall outlet

No accounting for stupidity I guess. Back in the day, sync cords for studio lights came with mains type plugs which plugged into the power pack.

noblepa · 11-13-2011, 07:58 PM

Originally posted by helhar

Hi,

Question 2: Is it safe to use the K-R with a sync cable? I have a small Porta-Flash system and an old Ascorlight (Berkey?) 800 ws power pack and heads (my preferred system). I have no clue how to determine the voltage they put out.

Many thanks.
Heller

Checking the trigger voltage is easy. Just use a small digital multimeter. You can probably buy one at Radio Shack for $20, or anywhere else for $5. Set the voltage scale to 200 volts DC. Then, charge up the flash and measure the voltage across the synch terminals.

Studio lights often use 1/4 or 1/8 inch phone plugs to sync. If you don't have a cable that makes it easy to access the two wires, you can buy an appropriate plug (mono, not stereo), remove the plastic and just measure across the solder or screw terminals on the plug.

As others have said, around 5v is ideal, but anything up to about 20 volts is probably safe. The lower the better. Some flashes have trigger voltages of over 300 volts, which can fry the electronics in your camera. If your flash is that high, don't connect it directly to your camera. Wein makes several devices of various configurations, called "safe sync", that will insure that the camera is never subjected to more than 5v.

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11-12-2011, 08:26 AM	#1
helhar New Member Join Date: Sep 2011 Posts: 1	Studio Flash Sync w/ K-R + Voltage Query Hi, I'd love some info on using my camera with studio lights. I recently purchased a K-R (my first DSLR), which has performed nicely, but I was unable to get it to sync to a Bowens monolight. I was using an inexpensive (and unreliable) wireless flash trigger, but even when the flash fired, it wasn't in sync. The camera didn't seem to recognize the light system. (I've successfully used this light and trigger with a Canon G-9) Unfortunately, I didn't have enough time to work through every combination of camera settings. I have strobes at home, and was going to try to find a workable combination of settings, using a sync cable running from the hot shoe. When I did some research, I read that I can fry the camera by using a system with high voltage. Question 1: What are the camera settings necessary to use a K-R with studio strobes? Question 2: Is it safe to use the K-R with a sync cable? I have a small Porta-Flash system and an old Ascorlight (Berkey?) 800 ws power pack and heads (my preferred system). I have no clue how to determine the voltage they put out. Many thanks. Heller

11-12-2011, 08:42 AM	#2
mannesty Senior Member Join Date: Mar 2008 Location: Totana - Murcia (Spain) Posts: 127	I'm not an experienced studio flash user, but I do use multiple flashes off-camera using radio triggers. #1 You must keep your shutter speed on or slower than 1/180th sec as that is the fastest synch speed that Pentax cameras are capable of using so far. #2 Yes you can use a synch cable. Check the trigger voltage of your flash units. Any modern unit should be OK and will probably have a synch voltage of around 5V. #3 Check the fastest shutter speed that your radio triggers can work at and whether they are compatible with your camera/flash combination. #4 You will almost certainly need to use a flash meter to achieve a correct exposure, and set your camera to manual exposure mode. As a rule of thumb, try ISO 100, 1/125th sec, f11, no EV or flash compensation. See what results you get.

11-12-2011, 08:53 AM	#3
Wheatfield Moderator Join Date: Apr 2008 Location: The wheatfields of Canada Posts: 15,981	With some of the less expensive triggers, you have to drop the shutter speed well below sync because of electronic delays. I haven't used Bowens units, but I did find with norman that I had to reverse the polarity of the contacts to allow the flash to fire with Pentax. The easiest way to do this is cut the sync cable and put a male and femal mains plug (2 prong extension cord ends) onto the wires so that you can reverse the leads. We had to do this so that I could use my cameras in the studio. Nikon was fine, Pentax is backwards. If the camera has a PC outlet, you should be fine with plugging into a studio light, but if you are using a shoe mount adapter, it's best to use a Safe-Sync of some sort to isolate the camera from the flash.

11-12-2011, 11:36 AM	#4
sterretje Veteran Member Join Date: Dec 2008 Location: Roodepoort, South Africa Photos: Gallery \| Albums Posts: 3,561	Originally posted by Wheatfield With some of the less expensive triggers, you have to drop the shutter speed well below sync because of electronic delays. I haven't used Bowens units, but I did find with norman that I had to reverse the polarity of the contacts to allow the flash to fire with Pentax. The easiest way to do this is cut the sync cable and put a male and femal mains plug (2 prong extension cord ends) onto the wires so that you can reverse the leads. We had to do this so that I could use my cameras in the studio. Nikon was fine, Pentax is backwards. If the camera has a PC outlet, you should be fine with plugging into a studio light, but if you are using a shoe mount adapter, it's best to use a Safe-Sync of some sort to isolate the camera from the flash. Your creativity sounds like that of a friend of mine who did that long ago with a head phone. Worked well till he one day by accident put it in the wall outlet

11-12-2011, 08:29 PM	#5
Wheatfield Moderator Join Date: Apr 2008 Location: The wheatfields of Canada Posts: 15,981	Originally posted by sterretje Your creativity sounds like that of a friend of mine who did that long ago with a head phone. Worked well till he one day by accident put it in the wall outlet No accounting for stupidity I guess. Back in the day, sync cords for studio lights came with mains type plugs which plugged into the power pack.

11-13-2011, 07:58 PM	#6
noblepa Veteran Member Join Date: Sep 2007 Location: Bay Village, Ohio USA Posts: 1,142	Originally posted by helhar Hi, Question 2: Is it safe to use the K-R with a sync cable? I have a small Porta-Flash system and an old Ascorlight (Berkey?) 800 ws power pack and heads (my preferred system). I have no clue how to determine the voltage they put out. Many thanks. Heller Checking the trigger voltage is easy. Just use a small digital multimeter. You can probably buy one at Radio Shack for $20, or anywhere else for $5. Set the voltage scale to 200 volts DC. Then, charge up the flash and measure the voltage across the synch terminals. Studio lights often use 1/4 or 1/8 inch phone plugs to sync. If you don't have a cable that makes it easy to access the two wires, you can buy an appropriate plug (mono, not stereo), remove the plastic and just measure across the solder or screw terminals on the plug. As others have said, around 5v is ideal, but anything up to about 20 volts is probably safe. The lower the better. Some flashes have trigger voltages of over 300 volts, which can fry the electronics in your camera. If your flash is that high, don't connect it directly to your camera. Wein makes several devices of various configurations, called "safe sync", that will insure that the camera is never subjected to more than 5v.