Can a flash damage a DSLR? (Vivitar 225 Auto Thyristor)

[trevor_christensen]

I read on Strobist (sorry, can?t find the link to exactly where) that you have

to be careful when using an older flash with a DSLR.

 

I?m looking for someone to shed some light (!) on the subject. Specifically on

the Vivtar Auto Thyristor 225.

 

In this post: http://www.photo.net/bboard/q-and-a-fetch-msg?msg_id=003tuA Thomas

says that the flash in question puts out 177v, but when my dad measured the

voltage across the contact pins (when fully charged) the meter showed 42V.

 

How can I tell what kind of flash will damage my camera? (Pentax *istD S2)

[ronald_moravec1]

I take no chances and use a Wein Safe Sync. High trigger voltage will damage even full mechanical cameras over time.

 

When the electronic control cameras first came out, it was recommended to turn off the flash and discharge it beforre mounting or dismounting. Digi cams hare probably more sensitive.

 

I would call Pentax for a direct answer to your question.

[sal b]

A general recommendation for safety with digital cameras in the past has been <b>6V or less</b> measured across the flash terminals, although Canon says specified newer models of its cameras will take up to 125V safely.<p>

 

As Ronald suggested, above, you should contact Pentax or see if the info about safe flash trigger voltage is found anywhere in your camera manual.<p>

 

A Wein safe sync unit costs about $50 but could save the internals of your camera in any case; or put the $50 toward a modern flash made to work with Pentax digitals [including aftermarket brands such as SunPak].<p>

[john_sutton9]

I have an old Vivitar 283 and it's filters that I'd like to use w/ my XTI. I've been wondering about being able to use it on a flash bracket instead of w/ the hot shoe. Strobist says it's way too hot, but I wasn't sure it that was hot shoe mount or w/ the flash cable. Any suggestions on this?

[savagesax]

Most likely no, but if a resister fries and lets in lots of volts from the flash, yes this could do damage.some the the capacitors can hold 400 and more volts, so if, the resister leak occurs your camera may be down for a bit.

[steve m smith]

Most high voltage flash trigger circuits consist of a small capacitor which is charged from the high voltage supply (300-400v) via a resistor which has a very high resistance. Usually about 1 Megohm. On firing the shutter, the charge in the capacitor is discharged into the trigger coil to fire the flash.<BR><BR> Because of the high value of this resistor, most meters being used to check the voltage will pull the level down a bit due to its own internal resistance.<BR><BR>

For example, if the meters internal resistance is 1 Megohm as well, the actual trigger voltage will be about twice that measured by the meter.<BR><BR>

You will need a very high input resistance meter to make an accurate measurement.<BR><BR>

However, check your camera's manual. Most Nikons are o.k. up to 250 volts as are some Canons.

[dave404]

I was trying to use my old Sunpak and found a paper that showed it pumps out 200Volts plus. I was lucky, no damage.

 

Here is a good reference.

 

http://www.botzilla.com/photo/strobeVolts.html