Using an old pre digital flash gun with a K10D

saladfunky · 01-05-2011, 05:29 AM

I have a K10D and have been warned not to use my old cobra ttl flash gun with it as there may be risk of electrical damage to the camera. Is this advice good advice or could I use the gun without worry?

Many thanks

Chris

Ira · 01-05-2011, 07:41 AM

Which model?

According to this list (scroll down), only one of four models ISN'T safe:

Photo Strobe Trigger Voltages

sterretje · 01-05-2011, 08:30 AM

Please note I'm guessing here !! An educated guess in my opinion but still a guess.

If it's ttl, there is electronics involved for communication with the camera. In my opinion this would imply that it's safe.

To be sure, you can measure the voltage on the main contact of the flash when it is charged (and not connected to the camera).

Adam · 01-05-2011, 08:43 AM

Moving this to the accessories section- it's not really about a current problem.

Adam
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alohadave · 01-05-2011, 09:42 AM

Originally posted by sterretje

Please note I'm guessing here !! An educated guess in my opinion but still a guess.

If it's ttl, there is electronics involved for communication with the camera. In my opinion this would imply that it's safe.

To be sure, you can measure the voltage on the main contact of the flash when it is charged (and not connected to the camera).

The TTL signals are safe. What you have to worry about is the trigger voltage. There are many old flashes that can do TTL that still have very high trigger voltages.

SOldBear · 01-05-2011, 11:50 AM

Originally posted by saladfunky

... my old cobra ttl flash gun...

Chris,

If you list the model of the flash gun, you may get more meaningful replies.

saladfunky · 01-07-2011, 02:43 AM

Hello and Thanks for the responces. I have a Cobra dedicated D650 LCD system flash gun which I bought in the late eighties I think. A great gun when I used it with my super A. Fingers crossed I can still use it with my K10D?

thanks

Chris

saladfunky · 01-07-2011, 02:45 AM

Originally posted by alohadave

The TTL signals are safe. What you have to worry about is the trigger voltage. There are many old flashes that can do TTL that still have very high trigger voltages.

Hi, thanks for the reply, does anyone know how to measure the trigger voltage to check this? It is a cobra D650 LCD system flash gun.

cheers

Chris

Ira · 01-07-2011, 04:20 AM

Originally posted by saladfunky

Hello and Thanks for the responces. I have a Cobra dedicated D650 LCD system flash gun which I bought in the late eighties I think. A great gun when I used it with my super A. Fingers crossed I can still use it with my K10D?

thanks

Chris

It's safe, Chris--only 5.6 volts. See my linked list above. (I love being the bearer of good news.)

To test, you use a voltmeter contacted to both terminals of the sync cord, and just turn the unit on. (You don't fire it or anything.) Make sure the unit is fully charged, or you have fresh batteries in there.

There's a shoe adapter called a Wein Safe-Sync which will reduce the trigger voltage of any flash down to 6 volts, but it ain't cheap--50 plus bucks. I needed a PC sync cord solution for one of my old flashes (safe voltage), since the K-x doesn't have a sync connection, and I debated whether to buy it. It goes in the shoe, retains hot shoe functionality, but also has a PC Sync port.

Being cheap and poor, I went for the less expensive $15 shoe-to-PC adapter only, but I really want to get one of these for my smaller, unsafe flashes.

saladfunky · 01-10-2011, 02:53 AM

Originally posted by Ira

It's safe, Chris--only 5.6 volts. See my linked list above. (I love being the bearer of good news.)

To test, you use a voltmeter contacted to both terminals of the sync cord, and just turn the unit on. (You don't fire it or anything.) Make sure the unit is fully charged, or you have fresh batteries in there.

There's a shoe adapter called a Wein Safe-Sync which will reduce the trigger voltage of any flash down to 6 volts, but it ain't cheap--50 plus bucks. I needed a PC sync cord solution for one of my old flashes (safe voltage), since the K-x doesn't have a sync connection, and I debated whether to buy it. It goes in the shoe, retains hot shoe functionality, but also has a PC Sync port.

Being cheap and poor, I went for the less expensive $15 shoe-to-PC adapter only, but I really want to get one of these for my smaller, unsafe flashes.

thanks for the replies, I got the same voltage result when I tested it so have tried using the gun on the K10D. I got some good shots ,some overexposed and some under. I get the feeling the gun doesn't work on the K10D like it did on the super A. With the super A it would expose perfectly no matter what I did to the aperture thanks to the ttl metering. Do you think the ttl doesn't work on a K10D? I need to find my manuals I think. But has anyone else had success?

thanks

Chris

Steve Beswick · 01-10-2011, 03:13 AM

Originally posted by saladfunky

thanks for the replies, I got the same voltage result when I tested it so have tried using the gun on the K10D. I got some good shots ,some overexposed and some under. I get the feeling the gun doesn't work on the K10D like it did on the super A. With the super A it would expose perfectly no matter what I did to the aperture thanks to the ttl metering. Do you think the ttl doesn't work on a K10D? I need to find my manuals I think. But has anyone else had success?

thanks

Chris

The K10d does not support ttl flash metering. In other words, you are correct. The flash gun does not work on the K10d like it would with the Super A.

saladfunky · 01-11-2011, 03:03 AM

Originally posted by Steve Beswick

The K10d does not support ttl flash metering. In other words, you are correct. The flash gun does not work on the K10d like it would with the Super A.

Thanks for that, so I have the option of auto or manual modes left on the cobra D650. Has anyone else used this combination successfully? K10D and cobra D650? or similar? Other question is how would a modern flash work on the K10D? Is TTL now old school?

thanks, I'm learning alot

Chris

Ratmagiclady · 01-11-2011, 04:49 AM

Originally posted by saladfunky

Thanks for that, so I have the option of auto or manual modes left on the cobra D650. Has anyone else used this combination successfully? K10D and cobra D650? or similar? Other question is how would a modern flash work on the K10D? Is TTL now old school?

thanks, I'm learning alot

Chris

Old-fashioned auto mode ought to work just fine for you with that unit, possibly with a little correction by now, ...Pentax digitals since some years ago (One of the *ist D-models? Not sure.) have a newer TTL flash metering protocol called P-ttl, which is actually through-the-lens, but based on measuring a little pre-strobing of the tube in the instant before the actual shutter opens, rather than shutting down the actual flash duration during the exposure like 'true' ttl.

It's not a popular thing about this system, (particularly when it comes to how long it's taken for there to be very many fully-compatible automated flash options: I'm kind of hoping future models will find a way to work the old true TTL option back in somehow: there are advantages to it. ) but a newer P-ttl flash will work OK, if you get hold of one of those too.

If that's making sense: I'm up pretty early this morning.

Anyway, the old 'auto' flash just has a little 'electric eye' on the flash itself which tells the flash when to cut its own duration off: barring anything fooling it or exceeding range limits, it gives light to deliver proper exposure at the f-stop selected.

(True TTL essentially does the same thing, but the 'electric eye' is in the camera, so it can be more direct and precise. )

I like the old 'auto' just fine, though, actually: it's a pretty convenient way to balance the ambient light and what the flash adds. You just tend to get fewer choices of aperture ranges.

Steve Beswick · 01-11-2011, 05:31 PM

Originally posted by Ratmagiclady

Old-fashioned auto mode ought to work just fine for you with that unit, possibly with a little correction by now, ...Pentax digitals since some years ago (One of the *ist D-models? Not sure.) have a newer TTL flash metering protocol called P-ttl, which is actually through-the-lens, but based on measuring a little pre-strobing of the tube in the instant before the actual shutter opens, rather than shutting down the actual flash duration during the exposure like 'true' ttl.

It's not a popular thing about this system, (particularly when it comes to how long it's taken for there to be very many fully-compatible automated flash options: I'm kind of hoping future models will find a way to work the old true TTL option back in somehow: there are advantages to it. ) but a newer P-ttl flash will work OK, if you get hold of one of those too.

If that's making sense: I'm up pretty early this morning.

Anyway, the old 'auto' flash just has a little 'electric eye' on the flash itself which tells the flash when to cut its own duration off: barring anything fooling it or exceeding range limits, it gives light to deliver proper exposure at the f-stop selected.

(True TTL essentially does the same thing, but the 'electric eye' is in the camera, so it can be more direct and precise. )

I like the old 'auto' just fine, though, actually: it's a pretty convenient way to balance the ambient light and what the flash adds. You just tend to get fewer choices of aperture ranges.

I'd like to second what RML said, and add that ttl is in many ways overrated. As far as pttl is concerned, I'd rather just use auto mode on my "old school" flash. It works better and is less confusing to the people in the photo.

SOldBear · 01-11-2011, 05:50 PM

Chris,

I did a little search and found this. I assume your flash is the same.

If the trigger voltage is good, I would use it. I notice that it has TTL, which is useless, and variable ratio manual, which is good, and auto with its own light sensor, which is good.

Try this: set the flash to auto mode and ISO to 400. Notice the aperture indicated by the flash. Now set your camera to M, shutter speed 1/180 or lower, ISO and aperture the same as on the flash. Then fire some test shots. You should have reasonable exposure.

I have 2 copies of Pentax AF540FGZ, but I'm still using it in auto mode, and still using many old flash guns.

01-05-2011, 05:29 AM	#1
saladfunky New Member Join Date: Mar 2010 Location: Bedfordshire Posts: 7	Using an old pre digital flash gun with a K10D I have a K10D and have been warned not to use my old cobra ttl flash gun with it as there may be risk of electrical damage to the camera. Is this advice good advice or could I use the gun without worry? Many thanks Chris

01-05-2011, 08:30 AM	#3
sterretje Veteran Member Join Date: Dec 2008 Location: Roodepoort, South Africa Photos: Gallery \| Albums Posts: 3,561	Please note I'm guessing here !! An educated guess in my opinion but still a guess. If it's ttl, there is electronics involved for communication with the camera. In my opinion this would imply that it's safe. To be sure, you can measure the voltage on the main contact of the flash when it is charged (and not connected to the camera). Last edited by sterretje; 01-05-2011 at 08:42 AM.

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01-05-2011, 07:41 AM	#2
Ira Inactive Account Join Date: Mar 2009 Location: Coral Springs, FL Photos: Gallery \| Albums Posts: 5,216	Which model? According to this list (scroll down), only one of four models ISN'T safe: Photo Strobe Trigger Voltages

01-05-2011, 08:43 AM	#4
Adam Administrator Site Webmaster Join Date: Sep 2006 Location: Arizona Photos: Gallery \| Albums Posts: 51,595	Moving this to the accessories section- it's not really about a current problem. Adam PentaxForums.com Webmaster (Site Usage Guide \| Site Help \| My Photography) PentaxForums.com server and development costs are user-supported. You can help cover these costs by donating or purchasing one of our Pentax eBooks. Or, buy your photo gear from our affiliates, Adorama, B&H Photo, KEH, or Topaz Labs, and get FREE Marketplace access - click here to see how! Trusted Pentax retailers:

01-05-2011, 09:42 AM	#5
alohadave Veteran Member Join Date: Jan 2008 Location: Quincy, MA Photos: Gallery \| Albums Posts: 2,024	Originally posted by sterretje Please note I'm guessing here !! An educated guess in my opinion but still a guess. If it's ttl, there is electronics involved for communication with the camera. In my opinion this would imply that it's safe. To be sure, you can measure the voltage on the main contact of the flash when it is charged (and not connected to the camera). The TTL signals are safe. What you have to worry about is the trigger voltage. There are many old flashes that can do TTL that still have very high trigger voltages.

01-05-2011, 11:50 AM	#6
SOldBear Veteran Member Join Date: Feb 2009 Location: Alameda, CA Posts: 3,206	Originally posted by saladfunky ... my old cobra ttl flash gun... Chris, If you list the model of the flash gun, you may get more meaningful replies.

01-07-2011, 02:43 AM	#7
saladfunky New Member Join Date: Mar 2010 Location: Bedfordshire Posts: 7 Original Poster	Hello and Thanks for the responces. I have a Cobra dedicated D650 LCD system flash gun which I bought in the late eighties I think. A great gun when I used it with my super A. Fingers crossed I can still use it with my K10D? thanks Chris

01-07-2011, 02:45 AM	#8
saladfunky New Member Join Date: Mar 2010 Location: Bedfordshire Posts: 7 Original Poster	Originally posted by alohadave The TTL signals are safe. What you have to worry about is the trigger voltage. There are many old flashes that can do TTL that still have very high trigger voltages. Hi, thanks for the reply, does anyone know how to measure the trigger voltage to check this? It is a cobra D650 LCD system flash gun. cheers Chris

01-07-2011, 04:20 AM	#9
Ira Inactive Account Join Date: Mar 2009 Location: Coral Springs, FL Photos: Gallery \| Albums Posts: 5,216	Originally posted by saladfunky Hello and Thanks for the responces. I have a Cobra dedicated D650 LCD system flash gun which I bought in the late eighties I think. A great gun when I used it with my super A. Fingers crossed I can still use it with my K10D? thanks Chris It's safe, Chris--only 5.6 volts. See my linked list above. (I love being the bearer of good news.) To test, you use a voltmeter contacted to both terminals of the sync cord, and just turn the unit on. (You don't fire it or anything.) Make sure the unit is fully charged, or you have fresh batteries in there. There's a shoe adapter called a Wein Safe-Sync which will reduce the trigger voltage of any flash down to 6 volts, but it ain't cheap--50 plus bucks. I needed a PC sync cord solution for one of my old flashes (safe voltage), since the K-x doesn't have a sync connection, and I debated whether to buy it. It goes in the shoe, retains hot shoe functionality, but also has a PC Sync port. Being cheap and poor, I went for the less expensive $15 shoe-to-PC adapter only, but I really want to get one of these for my smaller, unsafe flashes.

01-10-2011, 02:53 AM	#10
saladfunky New Member Join Date: Mar 2010 Location: Bedfordshire Posts: 7 Original Poster	Originally posted by Ira It's safe, Chris--only 5.6 volts. See my linked list above. (I love being the bearer of good news.) To test, you use a voltmeter contacted to both terminals of the sync cord, and just turn the unit on. (You don't fire it or anything.) Make sure the unit is fully charged, or you have fresh batteries in there. There's a shoe adapter called a Wein Safe-Sync which will reduce the trigger voltage of any flash down to 6 volts, but it ain't cheap--50 plus bucks. I needed a PC sync cord solution for one of my old flashes (safe voltage), since the K-x doesn't have a sync connection, and I debated whether to buy it. It goes in the shoe, retains hot shoe functionality, but also has a PC Sync port. Being cheap and poor, I went for the less expensive $15 shoe-to-PC adapter only, but I really want to get one of these for my smaller, unsafe flashes. thanks for the replies, I got the same voltage result when I tested it so have tried using the gun on the K10D. I got some good shots ,some overexposed and some under. I get the feeling the gun doesn't work on the K10D like it did on the super A. With the super A it would expose perfectly no matter what I did to the aperture thanks to the ttl metering. Do you think the ttl doesn't work on a K10D? I need to find my manuals I think. But has anyone else had success? thanks Chris

01-10-2011, 03:13 AM	#11
Steve Beswick Veteran Member Join Date: Apr 2009 Location: Ontario, California Photos: Gallery Posts: 1,736	Originally posted by saladfunky thanks for the replies, I got the same voltage result when I tested it so have tried using the gun on the K10D. I got some good shots ,some overexposed and some under. I get the feeling the gun doesn't work on the K10D like it did on the super A. With the super A it would expose perfectly no matter what I did to the aperture thanks to the ttl metering. Do you think the ttl doesn't work on a K10D? I need to find my manuals I think. But has anyone else had success? thanks Chris The K10d does not support ttl flash metering. In other words, you are correct. The flash gun does not work on the K10d like it would with the Super A.

01-11-2011, 03:03 AM	#12
saladfunky New Member Join Date: Mar 2010 Location: Bedfordshire Posts: 7 Original Poster	Originally posted by Steve Beswick The K10d does not support ttl flash metering. In other words, you are correct. The flash gun does not work on the K10d like it would with the Super A. Thanks for that, so I have the option of auto or manual modes left on the cobra D650. Has anyone else used this combination successfully? K10D and cobra D650? or similar? Other question is how would a modern flash work on the K10D? Is TTL now old school? thanks, I'm learning alot Chris

01-11-2011, 04:49 AM	#13
Ratmagiclady Veteran Member Join Date: Nov 2008 Location: GA Photos: Gallery \| Albums Posts: 13,563	Originally posted by saladfunky Thanks for that, so I have the option of auto or manual modes left on the cobra D650. Has anyone else used this combination successfully? K10D and cobra D650? or similar? Other question is how would a modern flash work on the K10D? Is TTL now old school? thanks, I'm learning alot Chris Old-fashioned auto mode ought to work just fine for you with that unit, possibly with a little correction by now, ...Pentax digitals since some years ago (One of the *ist D-models? Not sure.) have a newer TTL flash metering protocol called P-ttl, which is actually through-the-lens, but based on measuring a little pre-strobing of the tube in the instant before the actual shutter opens, rather than shutting down the actual flash duration during the exposure like 'true' ttl. It's not a popular thing about this system, (particularly when it comes to how long it's taken for there to be very many fully-compatible automated flash options: I'm kind of hoping future models will find a way to work the old true TTL option back in somehow: there are advantages to it. ) but a newer P-ttl flash will work OK, if you get hold of one of those too. If that's making sense: I'm up pretty early this morning. Anyway, the old 'auto' flash just has a little 'electric eye' on the flash itself which tells the flash when to cut its own duration off: barring anything fooling it or exceeding range limits, it gives light to deliver proper exposure at the f-stop selected. (True TTL essentially does the same thing, but the 'electric eye' is in the camera, so it can be more direct and precise. ) I like the old 'auto' just fine, though, actually: it's a pretty convenient way to balance the ambient light and what the flash adds. You just tend to get fewer choices of aperture ranges.

01-11-2011, 05:31 PM	#14
Steve Beswick Veteran Member Join Date: Apr 2009 Location: Ontario, California Photos: Gallery Posts: 1,736	Originally posted by Ratmagiclady Old-fashioned auto mode ought to work just fine for you with that unit, possibly with a little correction by now, ...Pentax digitals since some years ago (One of the *ist D-models? Not sure.) have a newer TTL flash metering protocol called P-ttl, which is actually through-the-lens, but based on measuring a little pre-strobing of the tube in the instant before the actual shutter opens, rather than shutting down the actual flash duration during the exposure like 'true' ttl. It's not a popular thing about this system, (particularly when it comes to how long it's taken for there to be very many fully-compatible automated flash options: I'm kind of hoping future models will find a way to work the old true TTL option back in somehow: there are advantages to it. ) but a newer P-ttl flash will work OK, if you get hold of one of those too. If that's making sense: I'm up pretty early this morning. Anyway, the old 'auto' flash just has a little 'electric eye' on the flash itself which tells the flash when to cut its own duration off: barring anything fooling it or exceeding range limits, it gives light to deliver proper exposure at the f-stop selected. (True TTL essentially does the same thing, but the 'electric eye' is in the camera, so it can be more direct and precise. ) I like the old 'auto' just fine, though, actually: it's a pretty convenient way to balance the ambient light and what the flash adds. You just tend to get fewer choices of aperture ranges. I'd like to second what RML said, and add that ttl is in many ways overrated. As far as pttl is concerned, I'd rather just use auto mode on my "old school" flash. It works better and is less confusing to the people in the photo.

01-11-2011, 05:50 PM	#15
SOldBear Veteran Member Join Date: Feb 2009 Location: Alameda, CA Posts: 3,206	Chris, I did a little search and found this. I assume your flash is the same. If the trigger voltage is good, I would use it. I notice that it has TTL, which is useless, and variable ratio manual, which is good, and auto with its own light sensor, which is good. Try this: set the flash to auto mode and ISO to 400. Notice the aperture indicated by the flash. Now set your camera to M, shutter speed 1/180 or lower, ISO and aperture the same as on the flash. Then fire some test shots. You should have reasonable exposure. I have 2 copies of Pentax AF540FGZ, but I'm still using it in auto mode, and still using many old flash guns.