Fill Flash with the Canon 20D?

I have a new Canon 20D and 580 EX flash. I'm looking for information on using
this combination for fill flash.

I grab a lot of non-professional (meaning stark amateur) photographs of people
in costumes at conventions (anime and SF conventions, if you must know).
Usually, the photos are outside, usually in the sun. The photos are not posed,
beyond just asking the model if I can take their picture. This gives me a lot
of harsh shadows, as you can imagine, as I can't really control the angle of
the sun relative to the model.

My previous camera was a Sony 717. I added a Vivitar 285 flash. With this
combination, I could set the automatic flash and the aperture for a flash fill
of about 2/3 stop under, just to soften the shadows. It seemed to work pretty
well when I also underexposed the picture by 2/3 stop also.

The Canon 20D and 580 EX flash combination has two exposure compensations, one
for the AE and one for the flash. The manual mentions fill flash, but doesn't
really go into the settings needed for this. I suspect there is some
combination of the settings, (possibly using manual for the exposure, possibly
using aperture priority), that will allow me to not worry about adjusting the
settings for every shot.

I'm looking for settings that I can use to point at a subject in the shadow,
then in harsh sunlight, and get good enough photos, but with automatic flash
fill when needed.

Anyone done any flash fill, and have any suggested settings for the Canon 20D?

Jerry

(Sorry about the cross-post, but Earthlink doesn't have the
rec.photo.digital.slr-systems newsgroup yet, so please post to
rec.photo.digital.)

 

Your equipment is a generation newer than mine but I'll offer that program
mode and Av mode will both provide what you want.

 

Program mode will assume the flash is the only source of light for the
subject and adjust aperture, shutter speed, and flash output accordingly.
Av will assume flash will light the subject, but adjust shutter speed for
background ambient light. So I'd say they could be very different depending
on ambient light conditions.

Mark

 

Actually, ETTL does that in program mode, too...

 

Howdy Jerry,

The definition of fill flash varies based on lighting condition and
ISO. Really, what we're talking about is playing with the mixture of
flash light to ambient light, and in a fill flash situation, the
desire is to have mostly ambient light, and just a taste of flash to
punch in the shadows.

One way to guarantee a given amount of ambient light with just a taste
of fill flash is to use Tv modes. Pick a shutterspeed that gives you
the level of ambient light that looks right, and let the camera fill
in the rest for proper expsoure. Warning though, your max flash sync
speed can get in the way here on the top end.

Another way is to use P mode and vary the ISO setting. Higher ISOs
should give you more of an available light mix, lower isos will call
in more flash to make the exposure.

Yet another way is to play with exposure compensation. An old trick
to get more available light and less flash is to go +1 stop on the
main exposure compensation, and -1 stop on the flash exposure
compensation.

I'm not sure there's any one setting that'll work best regardless of
the situation. Try P mode on ISO 200 for starters, and tweak from
there.

Best Regards,

 

Todd,

My original reason for the post was to get some fill flash on outdoor shots,
to fill in the harsher shadows at a convention I was going to. It was cold
enough outside that day that there wasn't anyone outside.

I used a bit of fill on the stage presentations, however (and thereby hangs a
tale).

The Canon 20D will sync at up to 1/250. The 580EX has a high-speed flash mode,
that lets the camera know it can shoot above that speed. I set the flash for
that mode, but I don't think I ever used a speed above 1/250. Maybe if I were
outside, I could have used it at 1/1000 or so. Maybe during this Christmas
break, I can get a chance to go to Venice Beach, and photograph some of the
bodybuilders there. That should give me a good chance to test out the higher
speeds in the bright sun.

I made the mistake of using the P mode on the stage pictures I took. The
camera set the speed to 1/60 (with ISO 800) even with the minimal lighting on
the small stage. I had the flash set at -2/3 a stop. The problem I had was
that the contestants were moving quite a bit. And even with the low lighting,
the camera still exposed the stage light pretty well, but exposed the
costumers with the flash. This caused a lot of blurring. Next time, I will go
to full manual and set the speed to 1/125 or 1/200, and let the flash do most
of the work.

Another thing I found out fairly quickly was to not turn on the "safety"
parameter in the camera, as it will change the speed of the Tv mode when there
is not enough light, even if you want the flash to do all the job. With this
setting on, the camera will reduce the speed of the shutter, overriding the Tv
setting. I got a few several second shots this way, when I really wanted to
use 1/250 and the flash for the light.

On the 20D, the camera will attempt to set the speed and F ratio to expose the
background properly (in all modes except manual), even if you have the flash
on. It will then use the flash to expose the subject in the center properly.
So, it is usually better to go -2/3 or -1 on the camera, then +1 or so on the
flash, to fill the subject properly.

Supposedly, the Canon has an auto-fill when the flash is on that will drop the
flash power in lighter scenes, to just a fill level. That is why I need to
take a lot of outdoor shots and determine the best fill settings in sunlight.
I may go up into the mountains in the forest, to get some harsh shadows to try
the best settings.

With P mode and flash, at any ISO, the shutter speed is limited to 1/60 to
1/250, and the aperture is adjusted accordingly. So I'll probably use a fixed
Tv mode, at 1/1000 or so to stop the action, then use the highspeed flash mode
for fill. I may even set the camera in full manual, exposing for the sun, then
using the flash for fill. That's probably the way I'll go when I go to the
next Muscle Beach competition, as the sun is usually bright all day.

Thanks for the information,

Jerry

 

Anyone done any flash fill, and have any suggested settings for the

In my experience, the best way to get fill flash to work right is to
use a manual flash. The manual flash also opens up lots of new
possibilities, and at $70 doesn't even cost much.

-Joel