Vivitar Zoom Thyristor 5200 Flash

aacerda · 10-15-2010, 11:19 AM

i recently bought a Vivitar Zoom Thyristor 5200 Flash. could i be able to use this on my pentax k-m(k2000).

please advice.
thank you very much
anthony

SOldBear · 10-15-2010, 12:20 PM

Originally posted by aacerda

i recently bought a Vivitar Zoom Thyristor 5200 Flash. could i be able to use this on my pentax k-m(k2000).

I think so. I had one before and used it with my K10D. As I remember, the trigger voltage is about 7V.

But you need to measure the trigger voltage of your unit to be sure. Let the flash charges up (ready light on), use a digital multimeter to measure the voltage from the center pin at the foot to the side terminal at either side of the foot. If it's less than X volts, the flash is safe to use.

Note: there is no consensus as what X should be. I use 24.

This table reports 9.4V. It's still safe IMHO.

noblepa · 10-15-2010, 01:22 PM

Originally posted by aacerda

i recently bought a Vivitar Zoom Thyristor 5200 Flash. could i be able to use this on my pentax k-m(k2000).

please advice.
thank you very much
anthony

SOLDBear is right about the trigger voltage. If its too high, it might fry the electronics in your camera.

Even with a safe trigger voltage, you won't get full functionality from the camera. Specifically, your camera can only control a p-ttl flash. Your flash is not. The camera will fire the flash, but it won't control its output.

You will have to set the aperture manually. Set the shutter speed to 1/180 (does the k-m have an X speed on the dial? My K10D does). You may have to put the camera into M mode to do this.

Read the instructions for your flash, or read the calculator dial on the back. This will tell you what aperture to use for a given ISO value (you can't use auto-ISO). Your flash was designed for film cameras, which can't change ISO on the fly.

If the flash says, say, f/8, then set your lens to that value. Shoot. The thyristor will sense the light reflecting from the subject and vary the flash duration (and therefore the light output) accordingly. You may need to chimp your shots and fine tune the aperture a little bit.

Note that Pentax cameras will not fire the flash if the shutter speed is set faster than 1/180 second.

aacerda · 10-16-2010, 06:25 AM

thank you very much guys.. I really appreciate your inputs.

aacerda

10-15-2010, 11:19 AM	#1
aacerda Inactive Account Join Date: Jul 2010 Location: toronto Posts: 3	Vivitar Zoom Thyristor 5200 Flash i recently bought a Vivitar Zoom Thyristor 5200 Flash. could i be able to use this on my pentax k-m(k2000). please advice. thank you very much anthony

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10-15-2010, 12:20 PM	#2
SOldBear Veteran Member Join Date: Feb 2009 Location: Alameda, CA Posts: 3,206	Originally posted by aacerda i recently bought a Vivitar Zoom Thyristor 5200 Flash. could i be able to use this on my pentax k-m(k2000). I think so. I had one before and used it with my K10D. As I remember, the trigger voltage is about 7V. But you need to measure the trigger voltage of your unit to be sure. Let the flash charges up (ready light on), use a digital multimeter to measure the voltage from the center pin at the foot to the side terminal at either side of the foot. If it's less than X volts, the flash is safe to use. Note: there is no consensus as what X should be. I use 24. This table reports 9.4V. It's still safe IMHO.

10-15-2010, 01:22 PM	#3
noblepa Veteran Member Join Date: Sep 2007 Location: Bay Village, Ohio USA Posts: 1,142	Originally posted by aacerda i recently bought a Vivitar Zoom Thyristor 5200 Flash. could i be able to use this on my pentax k-m(k2000). please advice. thank you very much anthony SOLDBear is right about the trigger voltage. If its too high, it might fry the electronics in your camera. Even with a safe trigger voltage, you won't get full functionality from the camera. Specifically, your camera can only control a p-ttl flash. Your flash is not. The camera will fire the flash, but it won't control its output. You will have to set the aperture manually. Set the shutter speed to 1/180 (does the k-m have an X speed on the dial? My K10D does). You may have to put the camera into M mode to do this. Read the instructions for your flash, or read the calculator dial on the back. This will tell you what aperture to use for a given ISO value (you can't use auto-ISO). Your flash was designed for film cameras, which can't change ISO on the fly. If the flash says, say, f/8, then set your lens to that value. Shoot. The thyristor will sense the light reflecting from the subject and vary the flash duration (and therefore the light output) accordingly. You may need to chimp your shots and fine tune the aperture a little bit. Note that Pentax cameras will not fire the flash if the shutter speed is set faster than 1/180 second.

10-16-2010, 06:25 AM	#4
aacerda Inactive Account Join Date: Jul 2010 Location: toronto Posts: 3 Original Poster	thank you very much guys.. I really appreciate your inputs. aacerda