Any suggestions for a powerful (400ws) auto flash system for hand held use with a LF press camera (6X9, 4X5)? Is the new Lumedyne Signature Series auto or just TTL? Is it just Quantum vs. Lumedyne? Metz is just not powerful enough for hand-held LF... Regards, Mark Nowaczynski

-- Mark Nowaczynski (archivalprints@home.com), March 14, 2001

Answers

I use the Norman B400 with a softbox all the time and it is great. Totally manual but very easy to use. 400 ASA at 10'f22. If you really need Auto, go with the Quantum and as I recall, you can boost to 800ws. Cheers

-- Scott Walton (scotlynn@shore.net), March 15, 2001.

The Metz 60 series should do the trick. With a guide number of 197 it has worked for me shooting sports with a 4x5 press camera.

-- Dan Smith (shooter@brigham.net), March 15, 2001.

you can boost the q flash to 800w/s but it is still 400w/s per outlet, not all into one head. still it works well on auto and has many attractive features.

-- adam friedberg (asfberg@hotmail.com), March 15, 2001.

I have seen an auto head for the Norman system that you might be able to find used--the LH3--which I think works with the 200B pack (200WS). I gather it wasn't too successful, because they no longer make it, and they usually go for cheap. Probably not as good as the newer Quantum or Lumedyne heads, but if you happen to have a 200B setup, it might be worth looking into.

-- David Goldfarb (dgoldfarb@barnard.edu), March 16, 2001.

Anyone know the converstion from Watt seconds to Guide Number?

-- Bill Glickman (bglick@pclv.com), March 18, 2001.

"Anyone know the converstion from Watt seconds to Guide Number?" This is a silly ass question for the following reasons: Watt seconds is a measure of potential energy. A guide number is the measure of actual light output and is affected by several factors including the design of the flash tube, the design of the reflector, and the efficiency of the unit in converting the energy contained in the capacitors to output at the socket for the flash tube. Elinchrom in particular is very good about providing a comparison chart showing the different efficiencies of various Elinchrom head and reflector combinations.

-- Ellis Vener (evphoto@insync.net), March 21, 2001.

Ellis, I sincerely apalogize for asking such a "silly ass question."

Photographers are interested in the amount of light a flash can produce, not the amount of energy consumed by the flash system. There are assumptions made with everything in photography, including Guide Numbers, such as, film speed, reflector on the flash, distance of hypothetical subject, etc. There is assumptions also made with larger flashes rated in watt seconds. These assumption would provide for an approximate converstion value from Watt seconds to Guide Number. I forgot that values, hence my reason for asking such a "silly ass question." With no ballpark converstion available, photographers would not be able to calc. the amount of flash required for flashes rated in Watt seconds!

Maybe I can find a place on the internet that allows someone to ask his peers questions about these issues.... I will try the LF forum, its my understanding that's what that forum is for....oh, I just checked, this is the LF forum?? It's unfortunate that everyone is not blessed with your photographic expertise.

-- Bill Glickman (bglick@pclv.com), March 21, 2001.

An example of why trying to equate watt seconds to light output Bill is the difference in the efficiencies of 2000 watt second Norman vs. 2400 w/s Speedotron, Elinchrom and Balcar units. In my tests with various but similar proprietary reflectors, as comparing the output with bare tubes, and (exactly the same umbrellas, and softboxes revealed that the Norman was half as efficient as the Speedotron, which is turn was about a 1/3rd of a stop less efficent than the Elnchrom and a little lrss than 1/2 stop less efficient than the Balcars.

But with the long throw reflectors I can get a really concentrated and very bright beam out of the Elinchroms. You also have to consider the relative efficiencies of monoblocs versus pack and head systems, but that may also be effected by the how the cable is designed.

In short you could only construct such a table for the individual system of lights you are considering.

-- Ellis Vener (evphoto@insync.net), March 22, 2001.

Rewrite for clarity!

!An example of why trying to equate watt seconds to light output is the difference in the efficiencies of 2000 watt second Norman vs. 2400 w/s Speedotron, Elinchrom and Balcar units. My tests comparing the metered output in various configurations including bare tubes, similar but proprietary reflectors and with exactly the same umbrellas, and softboxes revealed that the Norman was half as efficient as the Speedotron, which is turn was about a 1/3rd of a stop less efficent than the Elinchrom and a little less than 1/2 stop (.4) less efficient than the Balcars. I used a Norman LH2400 head, Elinchrom S head, an older (silver bullet) Balcar U head and a Speedotron 102A head for the comparison. New(ish) flashtubes in all heads. The Elinchrom S head is modified to work on the Balcar packs, and the Speedotron was modified to work on the Norman pack. Packs used were a Norman P2000X and a Balcar A2400. All output was measured at 10ft from the lightemitting source: either the tube itself (in the case of baretube or proprietary reflectors) or from the open end of the umbrella or the front surface of the softbox (a Plume Wafer 100).

-- Ellis Vener (evphoto@insync.net), March 22, 2001.