[jsherman999]

Greetings fellow Pentaxians.

I have never used an external flash on my K100D, and I have the opportunity to buy a Vivitar zoom thyristor 3500 flash as part of a package.

Can I use this fash on my K100D? (The body it's being sold with is a Pentax MG.)

I did some googling, and I ran across some vague warnings about power and burning out... something... on a *istD if the wrong flash was used.

Is there any way I can verify that this flash will work safely with my camera body - any power ratings, etc that I should look at?

Thanks, I appreciate any help.

[pentagor]

According to this site, this flash is safe to use on DSLRs.
Important thing is trigger voltage, wich should be below 30V for Pentax DSLRs.
The other thing is, what you will be able to do with it. I think you will only be able to use it in manual mode.

[Steinback]

I was actually out looking at a used version of the same flash today, but I didn't have a chance to check the voltage level on the trigger. If I make it back to the store again tomorrow with my multimeter, I'll let you know what the voltage levels are. The link Pentagor posted suggests that the voltage output is acceptable for digital cameras, but I'm going to check for myself before buying. The other problem I ran into is that I didn't realize at the time that there are different versions of the flash for different camera bodies, and I'm not sure if the one I saw was a Pentax compatible unit (no manual included with it, hopefully it's marked somewhere on the body).

Have you managed to figure out if the data the Pentax version of the flash sends to the contacts on the camera hot shoe is compatible with the K100d/K10d? I've also been trying to find information from anybody else who has used the 3500 successfully with a current Pentax SLR and I have yet to find anything, positive or negative.

Do you have access to the flash manual before you buy the camera? I had been hoping that it might contain some useful information, but have yet to find a digital copy.

[pentagor]

I think none of the old flashes won't P-TTL comunicate with your K100d/K10d. This means, that you can use them only in manual mode. But I think it will work on istDL if the flash is Pentax TTL compatible.

[rormeister]

I'm using the Vivitar 2500 successfully. Tested the trigger voltage and with fresh batteries it peaks at about 11.13vdc. It takes a bit of experimentation to get exposure right, but hey, no film wasted Cheers!

[Steinback]

I made it back to the store, and tested the output voltage on the 3500 for you. The model I tested was at 8.9 volts, so unless Vivitar made more than one version the 3500 should work fine as a manual flash on your K100. I tested the flash on my K10 body and it fired fine and gave reasonably good exposures, but despite being the Pentax variant the flash didn't appear to be sharing any data with the camera body.

After playing around with both, I decided to spend roughly twice the money on a Vivitar 285HV for the extra features and shooting modes it had available.

[jfrejo]

I have one that I have been using with my K100D for awhile and it is fine. It seems to work fine exposure wise with a few adjustments as long as you set your apature and iso according to the charts on the flash.
John