--- *-CHILLED DELIRIUM-* <sfunp@scfn.thpl.lib.fl.us> wrote:
>
>
> On Fri, 7 Jun 2002, Richard Martin wrote:
>
> > I understand the basic principle of using the 283 as fill
> > flash and I agree completely that the ratio is unpredictable
> > using Auto. But how would you do this manually?
>
> Ok... You asked for it !
>
> The quick and dirty method...
>
> If your 283 is putting out a true 2800 BCPS (and some
> can go as low as 1400 BCPS...be sure to fire the flash
> several times to form the capacitor before doing any work
> -or- measurements !). Now, with the unit on
> full-power/manual,
> select the shutter speed, staying at -or below- synch speed.
> Set your aperture to match that speed for the ambient
> light (for a frontlighted subject, even if your subject
> is 1/4 lit or backlit).
>
> The table....(print it out small enough to carry it)
>
> Subject-flash distance in feet. Do not attempt to
> use a higher shutter speed than indicated for your
> camera.
> __________________________________________________________
> BCPS 1/30th 1/60th 1/125th 1/250th 1/500th |
> ----------------------------------------------------------
> 2800 4-5.5-10 6-8-13 8-11-18 10-14-20 13-18-30 |
> ----------------------------------------------------------
> 1400 3-4-7 4-5.5-9 6-8-13 7-10-15 9-13-20 |
> ----------------------------------------------------------
>
> You will notice three distances given for each
> BCPS/shutter speed combo. Using the 1st will yield
> a 1:2 lighting ratio (full fill). The 2nd distance
> gives a 1:3 (average fill) and the third 1:6 (slight
> fill).
> This works regardless of film speed !
> ************************
>
> It also eliminates those pesky calculations.
>
> A few notes:
> Since you are stuck with a particular distance
> for a given shutter/synch speed, it is easy to see how a
> zoom
> lens can be *very* valuable when working in this manner,
> enabling
> you to crop and recompose without altering your fill ratio.
>
> The value of a higher synch speed for working with
> fill-flash soon
> becomes apparent looking at this chart. If you're using a
> Leica
> with its 1/50th synch, you're quite limited compared to a
> camera
> with a leaf shutter and 1/500th synch. Yes, you can change
> shutter speeds (as long as you are at or below synch speed).
>
> One should practice this method and learn just what the
> different
> ratios will look like so they can be pre-visualized. It takes
> a
> little getting used to, but this is quick and accurate.
>
> --- Luis
>
Hi Luis:
In my understanding there are two basic ways to deal with a
fill-flash situation. One, set your camera exposure for the
ambient light, taking care to choose a shutter speed that will
sync with the flash, then adjust the output of the flash to get
the fill you want. Two, again set the camera exposure for the
ambient light, then adjust the flash-to-subject distance. I
don't see that the shutter speed has any relationship to what
the flash is doing or has anything to do with ratios. The
f/stop/shutter speed combination on the camera is your basic
exposure, with or without flash. The flash just provides some
fill to reduce the contrast. And the output of the flash is the
same regardless of what shutter speed you are using. In any
event, the flash duration of the 283 is always shorter than any
shutter speed you could use - about 1/1000sec in Manual and up
to 1/30,000sec in Auto.
A slow sync speed CAN present a problem when there is
movement in your subject. Then you can get "ghosting", where the
flash part of the photo is sharp but the ambient light part is
blurred. Perhaps this is what you are referring to. Of course,
you can get some interesting motion shots by deliberately
choosing a slow speed if your camera has rear curtain sync. But
that's a different situation.
Richard
=====
Richard Martin specializes in Cityscape and Waterscape stock photography as well as Children's Portraiture. E-mail: marphoto@yahoo.com
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