On the subject of preflashes: I'm aware of optical triggers that can
compensate for preflash but have never tried them. My first tactic
would be to eliminate the preflash so the question is: can it be turned
off? The preflash is only there to measure exposure in some automatic
mode. I reason that, if the flash can be fired in manual mode, the
flash should fire at full power and dispense with the pre-flash. So,
what does the user's manual say about this?
I tried to download a user's manual for the GM1 but it's not available
yet. So I got the user's manual for the GX7 thinking their
flash/exposure systems might be similar. The user's manual clearly
shows a manual flash setting for use with manual exposure control. It
also discusses manual exposure control. But the user's manual is very
brief on both subjects and totally moot on the subject of using them
together.
All of this caused me to wonder what the EM-5's manual has to say on the
subject. I was quite surprised to see that, not only does the EM-5
support fully manual flash for the little plug-in flash unit but also
supports power level control in 1/3 stop increments all the way down to
1/64. It even has settings in the menu going down to 1/128 but, for
reasons unknown, these values are not selectable. Probably, such low
settings are only valid for larger flash units. If you were so inclined
I suspect that the little flash unit could have its power turned down to
a level that has little effect on total exposure but would still be
strong enough to trigger external optical sensors.
Anyhow, if the GM1 supports a manual flash setting I think you can
dispense with preflash compensation for optically triggering external
flashes.
ps: Although I couldn't find a GM1 user's manual I thought to look in
the specs section of the review in DPReview. Under "flash modes" is
lists: "Auto, On, Off, Red-Eye, Slow Sync". Since the flash can be "On"
and not in "Auto" I will interpret "On" as a manual mode. Power control
too? Probably not likely.
Dr. Flash
On 12/13/2013 11:18 PM, usher99@xxxxxxx wrote:
> Perfect for use with
> OM flash and translatable for use with GM-1 which has the EFC but synch
> speed of 1/50th. Was looking into it for a tiny alternative kit but
> did not like the lack of hot shoe/pc socket or something. Just saw
> programmable sensitive optical triggers at B&H that can learn to ignore
> any preflashes for use on a small flash bracket. Don't know how well
> they work but haven't ever seen them before outside of the Metz
> flash/bracket option. We'll see.
>
> Fan of Drs. Flash, Mike
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