Re: [Leica] Different SF20 Thread (with an M6TTL)

[John Collier <jbcollier@home.com>]

The exposure compensation function works by reducing or increasing the total
amount of flash light. It does do this by varying the time the flash tube is
powered. Within its range of control it will be accurate (depending on the
reflectance of your subject and film stock). If the longest duration is not
enough (subject too far or aperture too small), you will get an underexposed
photo which the camera/flash will warn you of with the blinking flash symbol
in the viewfinder. If the shortest duration is too much (subject too close
or aperture too large), you will get an overexposed photo which the
camera/flash will NOT warn you of! It will signal a correct exposure even if
it is overexposed. You have to practice so that you get to know the limits
of what can be done.

John Collier

> From: "Chris Quinn" <cquinn@mail.sjcsf.edu>
> 
> The manual does little aside from warn me about batteries, but I'm curious
> about fill-flash in TTL. I'm guessing that setting the EVs down (three stop
> range either direction in 1/3 stop increments) will tell the little computer
> that I want less than full exposure from the flash based on that number;
> what the manual doesn't tell me is whether I'm actually underexposing the
> flash by, say, -1EV, so that I get a nice fill, or whether it's pulling back
> the intensity by -1EV, but extending the duration of the flash so that I end
> up with a 'properly exposed' image equal to that done at full power. The
> second option lacks logic, but so does an instruction manual which doesn't
> address the issue: so here we are.
> 
> Experience? In trying it, I found that it seemed to work, but only mostly.
> When I dialed -3EV in, it gave me a standard full-TTL exposure.... I get
> confused.
> 
> Has anyone found an url which explains the SF20 thoroughly?
>