View Single Post
  #5  
Old October 29th 04, 02:30 PM
bob
external usenet poster
 
Posts: n/a
Default

All Things Mopar wrote in
:

I hadn't thought of this being an issue and certainly didn't
know the voltages can and do vary. Are you suggesting the
Vivitar may have damaged my 5700? Is there a way for me to
find out what the firing voltage on my Vivitar 728 is? Can't
find it in their puny manual.


Power the flash up and read the voltage with a meter --
http://www.botzilla.com/photo/G1strobe.html

If it was too high, your camera would have probably failed by now.


I use Sunpak flashes with my CP 5000. They work really well. There is a
good bit of variance between the different ones I have, so I stick with
the lowest. I think it was $30 used.

I don't think there's anything wrong with your camera or your flash, but
I think there is a problem in how you are using it.

Does your 728 have a Nikon dedicated shoe (4 pins)?

What mode is your flash set to? If you use TTL mode, then the 5700 uses
the external sensor to squelch the flash, and if you have something near
the sensor, like your finger, it will reflect the light back and shut it
off.

If you are using the flash in an "automatic" mode, then the flash uses
it's own sensor, and you need to set the aperature according to the
automatic range in use.

If you have the flash set to automatic mode, and the camera set to
automatic mode, then the camera will try to control the flash, but will
not be able to and you will get unpredictable results.


Nikon told me to put the 5700 into full manual mode and
shoot with my Vivitar using its 92 guide number at ISO 100.
That'd be OK if the 5700 would tell me the distance it is
focusing to! Nikon said "well, just guess!". I did test both
the Speedlight and my Vivitar in various settings in my home
using just a simple tape measure, but haven't tried that in
a museum yet.


If you use auto mode on the flash, then your guess doesn't need to be
very good at all, only in the right range. The Sunpak 36dx I use has a GN
of about 120. The middle auto range (for f/4) runs from 3.3 feet to 30
feet.

Besides -- all you need to do is leave the monitor on and review the
shots with the histogram and you will know strait off if the exposure is
OK or not! It's not like cars in museums are action shots ;-)

Bob


--
Delete the inverse SPAM to reply