[Leica] Studio Flash Photography with M6 TTL

["The Adler Family" <badler@nanospace.com>]

Dear LUGers,

I have recently bought a M6 TTL, Summicron 35 and Elmarit 90, all new. As
this was a *somewhat* impulsive purchase, I must now sell my Nikon and
Contax systems. The Contax sale poses no problem, but I do use the Nikon
system to generate some income from portrait studio work. I use 3 Nikon
flashes with umbrellas and backdrop for this paying work.

My dilema is this; I would like to continue to do an occasional portrait
shoot using my Nikon flashes in conjunction with the M6. I use a Sekonic
meter to measure incident flash and then manually adjust flash output. The
Sekonic measures incident light from the flashes either at 1/30sec or
1/60sec shutter speed. I consider 1/30sec too slow for portraits (people
tend to blink, twitch, not to mention my espresso shakes) and the M6 has a
synch speed of 1/50 (frankly, I think this is a rather unusual synch speed,
but that's another thread). The Sekonic meter will show me incident light in
increments of 1/10 of a stop (e.g., f8, f8 & 1/10, f8 &2/10).

My theory as to how to adjust flash output using the Sekonic to correlate to
the 1/50 synch speed of the M6 is as follows. Let's take this example: I
want to take the shot at 1/50 f4. Because 1/50 is 1.2 times the amount of
exposure achieved with 1/60, I want the Sekonic to show, at a speed of 1/60,
an f-stop that is 0.2 times wider open than the f-stop of the camera: that
would be f2.8 + 8/10 stop. Assuming that the 1/10 stop indicators on the
Sekonic represent increments of light flow (not diameter), is my theory
correct?

Of course, I'll be shooting some rolls to test this out, but I thought I'd
run it past the experts to see if I was making a material blunder.

Thanks in advance for any help you can give.

Bob Adler