[MF3D.FORUM:1474] Re: NSA MF slide show

["David W. Kesner" <drdave@xxxxxxxxxx>]

Bill Glickman writes:

> not many people can fire 300 Gn flash, even a $1k
> top of the line Metz only offers about 145 GN.

I am starting to see many flashes with a "rated" GN of 160-180 
in feet with ASA 100. I quoted rated as many manufacturers 
highly over-rate their flashes. I highly recommend that anyone 
using a flash determine the actual GN with the 
camera/film/subject set up they use.

> The easiest way is to use a remote control slave made by Wien, it has a
> sensor on it that senses a flash....

I use a slave made specifically for cave photography. It is 
called the Firefly and is made in England by cavers. It uses 
IR cutoff as a trigger so random light flashes from caving 
lights won't set it off. It is also good out to about 1500 
feet and works around corners. Most of the light slaves (like 
the Wien) need direct line of site and are good for only a 
couple hundred feet. The other problem is that most light 
slave will not be fired by flashbulbs. I do have one Vivitar 
283 with a permanent Wien slave foot. I use this quite a bit 
for simple fill flash.

> The remote controls costs about
> $40 - $90, the more expensive ones cover greater distance

The FireFly sells for about $55.00.

> BTW, where do you get these flashes that fire bulbs this powerful?

Cress Photo is THE world's greatest site for flashbulbs. The 
URL is <http://www.flashbulbs.com/index.shtml> They carry all 
sorts of bulbs and guns and pans as well as the MeggaFlash 
bulbs.

> What is the highest powered bulb they make?

The pf300 will give a GN of 550 with an ASA of 80-125 and a 
shutter speed of 1/30th or less. They also have a pf330 bulb 
that is so powerful they don't have a GN for it. It is used 
mainly in high speed motion picture photography.

> I was always interested in
> these single use bulbs with awesome power....till now,

At $50.00 each you had really better be sure everything is set 
up right. I don't think you would want to do too much 
bracketting in a scene that used two or hree of these *{;-)

> I just carry 6
> flashes with me and put them around the scene...

That is the best approach. Just make sure to get the right 
distance from flash to subject so all the flashes are balanced 
to the same fstop. or use a flash with variable power settings 
or an auto setting. You can also use one flash and pop it off 
multiple times, but then you have to do all this math to know 
just how many times to fire. A flash with a GN of 100 flashed 
twice does NOT give a GN of 200!

David W. Kesner
Boise, Idaho, USA
drdave@xxxxxxxxxx