Anybody here ever measure the actual output of a Vivitar 285HV?
By a strange set of circumstances I have two of them in hand. One was
recently given to me by the former owner since the auto modes don't
work. The other was loaned to me by a friend with a request to see if I
could figure out why it doesn't fire from the hotshoe although it does
fire from the PC socket or the test button.
Turns out that one has a broken solder connection at the hot shoe
contact. The other one has a bad sensor module which I was able to
determine by substitution from the one with the bad solder connection.
Anyhow, when testing them I decided to check the max power output with
my flash meter. According to the spec they should give a guide number
of 120 at ISO 100 and diffuser set at the normal (50mm) position.
Measuring at exactly 10 feet one gives me f/8 and the other f/9 or guide
numbers of 80 and 90. Since that's about 1/3 stop difference I figure
that's probably within the manufacturing tolerances between flashes.
But they should be measuring f/12 and that's a stop or more difference.
In other words, only half the power that they're supposed to be
putting out.
When I've measured my T-32's and Sunpaks they've always shown to be bit
optimistic relative to the spec but nothing like 1 stop below what it's
supposed to be.
So, my question is, has anybody else actually measured a 285HV? Are
both of these units just getting old and tired or does Vivitar lie a lot
about guide numbers. Actually, while the one delivering actual guide
number 80 is probably 15-20 years old I don't think the other one is
more than a few years old.
ps: In case you haven't been watching lately, Vivitar has finally
discontinued the 283 and 285. You can't get new ones anymore.
Thanks,
Chuck Norcutt
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