Archived posting to the Leica Users Group, 1999/06/01
[Author Prev] [Author Next] [Thread Prev] [Thread Next] [Author Index] [Topic Index] [Home] [Search]The Adler Family wrote: > > 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 Bob, Shutter speed has nothing to do with flash exposure unless you have gobs of ambient that exceed flash exposure. Particularly in a somewhat controlled studio-type scenario 1/50 or 1/60 or 1/30 shouldn't make a difference. Even 1/30 your exposure will be frozen by flash unless subjects are really hopping around enough for the ambient to register. I use strobes with modelling lights and they don't even contribute that much. Just take the meter reading and go with it. - -- Carl Socolow http://members.tripod.com/SocPhoto/