Newsgroups: rec.photo
From: acs@csri.toronto.edu (Alvin Chia-Hua Shih)
Subject: Re: F4s, SB-24, what gives? 
Date: 17 Aug 92 19:23:51 GMT

In <bd8magh.hchong@netcom.com> hchong@netcom.com (Hoi Chong) writes:

>Well, a long time ago I had a (cheap) Fujica ST801 with a Vivitar 285.
>*Every* picture I took at a large birthday party was great!

			[...]

>The (HOVE) manual said that matrix metering flash may come out over-exposed
>due to bad printing for color negative.  I cannot afford pro lab, so changing
>lab is not an affordable solution. 

If you want less flash, use the SB-24 flash compensation control.  You
can tell the flash to give +1 to -3 stops of *flash* exposure.  So if your
flash subjects are washed out, but everything else is fine, try -2 or -3
stops.

Also, the TTL flash sensor is (probably) centre-weighted.  (Could someone
please confirm this?)  That means the camera only cares about the flash
exposure of the middle of the frame.  So, if your subject is off to the
side, it will not reflect enough light to the centre-weighted sensor to
cause a flash quench.

For off-centre flash subjects, some cameras have "flash exposure lock"
(Canon T-90, Contax RTS), others can be made to measure TTL flash on
different areas of the film plane (Canon EOS 10s--left, centre,
right).  With an F4s, I'd probably twiddle the flash exposure
compensation to -3 and pray.

Finally, you could just set your flash manually!  Just consult some old
book on flash photography and look up the power/aperture combinations
for a given flash-to-subject distance.  That's probably what you were
doing with your old Fujica/Vivitar combination!

This is especially easy if you *don't* have a zoom lens!  With a prime
lens, you are not inclined to change your flash-to-subject distance
because you want your subject (average-sized person's head and
shoulders) to occupy a certain proportion of the frame.  So, you only
have to change the settings every time you change lenses/focal length.
(Which, again, zooming screws up completely.)

So, you give up the ease of changing distances for allowing off-centre
shots.

>Please note that I have not done serious flash photography for a long time,
>so if I sounded too picky, it is due to ignorance.  Feel free to say so.

To strive for something better should never be a crime!

>Do we have to live with "front person too white while back person 2 feet back
>too dark" without going to ceiling bounce (not available)? 

Here, you are simply a victim of the "inverse square law".  The person in
back gets *much* less light due to the spreading of light.  To make the
effect less pronounced, stand back further so the relative amounts of
light reaching your subjects are more closely matched.

Also, there is a distance at which your subject is "too close" to the
flash for it to shut off in time.  I think it has something to do with
the time resolution of the TTL-flash circuitry.  Consult your manual
on this.

>What setting should I set my camera at?  M?  Aperture priority?  Shutter
>priority?  Program?

Program mode should work just fine.  (Except if your subject is off-centre
as mentioned above.)

>This is for a indoor party, ceiling sometimes not available deal.  Please
>give your experience with F4s/SB-24.  Thanks in advance.  

I'm surprised your flash accessories (bouncers, etc.) didn't work for you.
They are supposed to give more even lighting.  (Admittedly, I'm still trying
to decide on whether to get a "softbox" or a "bouncer".)  If you have the
$$$, you might try a flash bracket to hold your flash higher on the camera
so you can aim the flash down.  This should throw the shadows behind the
subject.  (Haven't tried this because I don't have the $$$, and don't take
a lot of people pictures.)

Another thing you can try in order to soften the light is manually zoom
the flash to its widest setting (24mm or something like that).  The
less directional the light, the better.

Nikon probably has a special, additional guide about the F4s and
SB-24.  Ask around.  (Canon has one, so I don't see why Nikon
wouldn't.)

I hope that helps.  Please let me know if you find a technique that works
for you.  (And if you get fed up with your Nikon system, I'll take it!  :-)

ACS
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