Marco,

> Ok Flash reflection on the desk is horrible... also the reflection on the
> subject glasses. no problem the groom will wear no glasses

Yeah. Watch out for those reflections. Shoot at an angle to all the
reflective surfaces if at all possible.

> IMG_3
> http://www.webalice.it/low.lyan/IMG_3.JPG
> This one is not so bad as for the light, but a little out of focus. Or so I
> think

I'd preferred if the background exposure on the left side of the frame
matched that of the right side of the frame. I love the ambient light,
but the flash on the wall kinda kills it.

> IMG_5
> http://www.webalice.it/low.lyan/IMG_5.JPG
> Good result, but at the back of the couple!! :(

... But the front of the priest. That might be a cool shot.

> IMG_9
> http://www.webalice.it/low.lyan/IMG_9.JPG

That is a really, really cool shot!!! Crop it to vertical from door
frame to door frame. Take out some of the black top. Then maybe stamp
out the brigh spot between his legs. That's a cool shot.

> IMG_12
> http://www.webalice.it/low.lyan/IMG_12.JPG
> Maybe too much attention given to the statue in the background don't you
> think?

I agree. But your subject is also a bit (maybe a full stop)
underexposed. At least it looks that way on my monitor. But you
definitely want the bride to be the brightest in the picture.

I have the impression that you're getting a bit confused here and as a
result, you're trying different things hoping to find something that
works. Let me help you along the way:

Background Exposure
The background exposure (the areas of the picture not covered by the
flash) is set by the aperture/shutter speed/ISO combo. Just like
normal when shooting without flash.

Foreground Exposure
The foreground (the area that IS covered by the flash) exposure is set
by the aperture and guide number (GN) of the flash. Note that the GN
varies with ISO (higher ISO --> higher GN). The maximum flash coverage
is calculated as (Max. Coverage) = (Guide Number) / (F-stop). The GN
for your 580EX is 58 meters (at ISO 100). So if you're shooting at
f/5.6, your maximum flash coverage will be roughly 10 meters (58/5.6 =
10.4 m). If you are using TTL metering and your subject is closer than
the max flash coverage, the TTL will cut off the flash when the
subject has been "properly" exposed. Properly in "" here as it really
means that the subject has been exposed to medium tone (if you're
using centerweighted average or whatever the matrix meter decided it
should get exposed to if you're using matrix mode) -- just like when
you're exposing without flash. If your subject is farther away than
the max flash coverage it will be underexposed (assuming the flash is
the only light source).

Does this make sense?

Now my suggestion (based on my preferences) would be to use manual
mode on the camera. Set the aperture such that the max flash coverage
covers the subject with a little safety margin to spare. Set the
shutter speed to proporly expose the background (or maybe even make it
a little dark overall). Expose for the bright spots on the statue in
the background and placing those around medium tone. That way the
flash will illuminate the subject and not much beyond it. The
background will be illuminated by whatever light is there.
Now, if this method gives you a shutter speed that's too low you have
two options: 1) Increase the ISO (which also increases noise). 2)
Decrease the power of the flash. I bet your flash has an option that
allows the power of it to be adjusted in full (or maybe half/third)
stops. For each stop you decrease the flash power, open up the
aperture by one stop. This makes it possible to use a faster shutter
speed and still get the same background exposure.


You asked previously if I would increase the flash exposure by 2/3 or
1 stop. I assume this refers to the light loss of the Sto-Fen
OmniBounce. You don't need to change any settings when you use a
diffuser such as the OmniBounce as long as you're using TTL metering.
The flash compensation works like regular exposure compensation except
that it changes the flash exposure (thereby the foreground exposure).


Tom
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