Pentax K-X & Using Strobes

sarahreed · 11-22-2010, 04:35 PM

I am new to using studio lighting and have a question -- I shoot manual exposure and connect the sync cord to my camera using a hot shoe. I meter my light using an external light meter, set my camera settings manual, focus, and then take the photo. Sometimes the camera fires the strobe, other times not. I am trying to figure out why. I ruled out faulty equipment. Someone in my class (I am a photography student) suggest that it might be because my camera won't trigger the strobe flash if the shutter speed is too slow.

Can anyone help out?

Again, I am really new to using studio lighting and so if anything isn't clear, please ask me to clarify! Thanks!

Tomzee93 · 11-22-2010, 06:46 PM

I'm not quite sure, but I believe the K-x will only trigger an external flash at shutter speed 1/180.

noblepa · 11-22-2010, 06:54 PM

Originally posted by Tomzee93

I'm not quite sure, but I believe the K-x will only trigger an external flash at shutter speed 1/180.

... or slower. All Pentax dslrs will synch at any speed less than or equal to 1/180 second.

Are you using any kind or radio or optical triggers, or are all the flashes connected with wires? There have been reports that some (especially the less expensive) radio slave triggers are very intermittent at the max. shutter speed of 1/180. Some users have reported having to slow down to 1/125 or so.

If you're connected via wires, it should be more reliable.

One thing, though. If using wires, I would check the trigger voltage when all those flashes are wired together. Some flashes can present very high voltage across the hotshoe, of 300 volts or more. This is dangerous for the electronic synchronization circuits in the camera. I don't think Pentax has ever stated a maximum voltage, but the concensus seems to be 25 volts or less, and the lower the better.

11-22-2010, 04:35 PM	#1
sarahreed Inactive Account Join Date: Nov 2010 Location: Flint Posts: 2	Pentax K-X & Using Strobes I am new to using studio lighting and have a question -- I shoot manual exposure and connect the sync cord to my camera using a hot shoe. I meter my light using an external light meter, set my camera settings manual, focus, and then take the photo. Sometimes the camera fires the strobe, other times not. I am trying to figure out why. I ruled out faulty equipment. Someone in my class (I am a photography student) suggest that it might be because my camera won't trigger the strobe flash if the shutter speed is too slow. Can anyone help out? Again, I am really new to using studio lighting and so if anything isn't clear, please ask me to clarify! Thanks!

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11-22-2010, 06:46 PM	#2
Tomzee93 Forum Member Join Date: Dec 2009 Location: Knoxville Photos: Gallery \| Albums Posts: 71	I'm not quite sure, but I believe the K-x will only trigger an external flash at shutter speed 1/180.

11-22-2010, 06:54 PM	#3
noblepa Pentaxian Join Date: Sep 2007 Location: Bay Village, Ohio USA Posts: 1,034	Originally posted by Tomzee93 I'm not quite sure, but I believe the K-x will only trigger an external flash at shutter speed 1/180. ... or slower. All Pentax dslrs will synch at any speed less than or equal to 1/180 second. Are you using any kind or radio or optical triggers, or are all the flashes connected with wires? There have been reports that some (especially the less expensive) radio slave triggers are very intermittent at the max. shutter speed of 1/180. Some users have reported having to slow down to 1/125 or so. If you're connected via wires, it should be more reliable. One thing, though. If using wires, I would check the trigger voltage when all those flashes are wired together. Some flashes can present very high voltage across the hotshoe, of 300 volts or more. This is dangerous for the electronic synchronization circuits in the camera. I don't think Pentax has ever stated a maximum voltage, but the concensus seems to be 25 volts or less, and the lower the better.