flash/optical slave problem

[jim hutchison]

I bought 2 Sigma EF-500 ST flashes for my Pentaxes. I ve the TTL
flash, but they don't behave very well with optical slaves on them...
they'll fire about every 4th or 5th flash from my master... even
with it inches away.

It's the same no matter what optical slave I use (I own 4 or 5), or
what flash they're on. I also have 2 Vivtar 285 flashes, and they
fire every time when on the same slave.

Any clue why this happens?


--jim

[zeitgeist]

seems like the internet requires people to make a snarky comment so here
goes....

sigma, well duh.

but I'm wondering if there is a voltage level problem, or if the polarity is
wrong. with HH blade plugs you could pull it and reinsert the other way and
quite often fix the problem.

this reply is echoed to the z-prophoto mailing list at yahoogroups.com

[jim hutchison]

Seemingly you don't like Sigma. Do you recommend a particular brand?

Anyways, if it was a polarity issue, they wouldn't work on my
camera... they behave just as they should when mounted on a hot shoe
(TTL, etc), but not the slaves. Plus, they won't fit on the other
way.

Thanks for your response anyways...