Outdoor flash

Roy Mathers wrote in post #5770597
Derek - a couple of questions. How does the camera know whether you are using the flash as your primary light source, or if you want it 'to properly expose the scene with ambient light'? Secondly, I don't understand how you can set the camera up in exactly the same way in 'M'.

The camera will always assume that ambient is your main source of light. IN AV, if you set f/5.6 the camera will adjust your shutter speed to get a proper exposure. Let's say that it comes up with a SS of 1/60s. So you are shooting and 1/60s and f/5.6, ISO 400. Now you turn on your flash and it "fills" in the shadows. The camera and flash should behave exactly the same if you set your camera on M and dial in 1/60s and f5.6, ISO 400 and use the flash. This is all assuming ETTL of course. For fill flash I personally set my FEC to around -2. If you leave it around 0 and your subject moves, you will get ghosting since the ambient and flash are exposing nearly equally.

You need to tell your camera that you want the flash to be the primary light source. With my settings above and in M, I would simply set my shutter speed to 1/250s This would mean that my ambient would now be underexposed by 2 stops. I then make sure my flash's FEC is set around 0. This is "telling" the camera that I want the flash to be the brightest light source, and that I am not concerned with letting the ambient light be responsible for exposure. My camera's meter should be at -2.

In AV mode, all I would need to do is set the camera's EC to -2, and leave the flash set around 0. this would in effect do the same as I did in M by underexposing the ambient and keeping the flash up around proper exposure.

This is of course a simplified explanation, and there are a ton of different ways to go about it.

Curtis N wrote in post #5770692
For what it's worth, my FEC setting for fill flash is typically about a stop less than if I'm using flash as the only light source. Usually +2/3 to +1 for flash as primary light, and -1/3 to 0 for fill. So I guess you could say the same theory applies.

I usually use +1 or +1 1/3 for primary, and -1 to -2 for fill. So obviously it can very by a lot depending on your situation and equipment. Preference also plays a part in this.

DDCSD wrote in post #5770777
If you leave it around 0 and your subject moves, you will get ghosting since the ambient and flash are exposing nearly equally.

This is more or less as I understood it. Your sentence quoted above illustrates one of the points I was trying to make generally - unless you dial in some minus FEC on the flash, it isn't really 'fill' flash, as both light sources are virtually equal. This, I suspect, is why you see so many pictures 'over flashed'.

I too usually use at least -1 when using fill, and it's interesting that Curtis only uses 1/3. Chacun a son gout!

ed rader wrote in post #5765349
Bobby -- you should be able to tone these down a bit i PP i'd think .... if that's what you want.

did you use an attachment on your flash?

ed rader

Ed, I had photoflex extra-small softbox on the 550ex.

bobbyz wrote in post #5771319
Ed, I had photoflex extra-small softbox on the 550ex.

Looks like it softened it up a fair amount. Might have to look into those.

bobbyz wrote in post #5771319
Ed, I had photoflex extra-small softbox on the 550ex.

For contrast, I had the next size up in the example image I posted. It was a Photoflex small and a Canon 580EX.