Re: [Leica] FILL FLASH

[Paul Kern <effeight@earthlink.net>]

Paul,
Correct me if I'm wrong, but diffusion material or spun glass on the
flash will only help if there is something (ceiling, wall) to act as
reflector of light emitted sideways from the diffusion.  Mostly all
diffusion material does is lower the color temperature slightly.  To
soften the image one must change the SIZE of the light source.  Slipping
on one of those blow up gizmos can do a little bit, making the light
source maybe four times larger.

Size of light source in reducing shadow contrast is what drives sales of
softboxes and light panels (I know, I have many!).  It is also
interesting to note that the softer the light the less color
saturation.  Pin point light source (the sun) and great, saturated
color.  Same with flash on camera strobe (as long as not too cold--a
common problem with most small strobes).  Large light source less
saturation.  Which is why some room set photographers (and occasional
people shooters) use a combination:  Large softbox with a pencil light
(basically a bare flash bulb) in the middle.  With this setup you get
nice saturation and open shadows.  Balcar has several light control
devices that work with this concept, and work well.

I do use the Stofen attachment and it works great in small spaces where
I want light to bounce around.  But if I used it in a gymnasium, all it
would do is use up batteries over coming a 2-stop loss.

donal
- - --
Donal Philby
San Diego


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You asked for it. You are totally wrong.

The size of the light source like the umbrellas and big reflectors I use in
the studio and their distance from the subject control the size of the
spectral highlights. The quality of light is controlled by what you put
over light. I like spun glass.

The  Stofen attachment, which I use sometimes, both softens the light, like
diffusion mateiral or spun glass, and bounces it from all the surfaces that
are close enough. If you're shooting chrome and the walls and ceiling are
anything but white you have a problem. It also eats about two stops. The
spun glass, depending on thickness, eats one-half to one-and-a-half stops.

What you want in fill flash is to open the shadows with soft light -- not
to illuminate the subect with directional light from the camera position.
The diffusion takes away the directionality of the fill light making your
fill flash less noticable.  If the diffusion material is neutral, it has
zero effect on color temp.

Paul