30D Exposure Technique

Would appreciate any insight offered on using a 580ex with a 30D. Camera is in "M" mode with the flash attached to the body. Technique wise, should I compose the picture and establish the shutter speed/aperture to center the exposure level and then let the flash automatically attempt to fill? I realize the shutter speed will affect how much of the scene gets exposed and I have the ability to go above synch speed for use of larger apertures. Basically, trying to understand what a start point is for camera exposure before working any EC or FEC. Thanks.

I use a 5D and the same flash. I use manual mode indoor. Typically I set a shutter speed and apeture I like (usually -2 to 3 stops underexposed) and let the flash automatically fill in. I tend to "drag" the shutter a bit (let the exposure go slow 1/30th or less). The flash typically "freezes" the action, but the background fills in. At weddings typically at some point they "dim the lights" making the background dark no matter what.

I think I'm flash exposure comp at -1/2 a stop.

I switch to Apeture priority outside.

When You use TV or AV (Shutter or apeture) priority the camera seems to try to get the exposure right without the flash and then uses the flash as fill. This results in shooting wide open or really long shutter speeds.

Hope this helps.

some examples of this:

http://www.plocp.com/display_roll.php?folder_name=/wedding_preview&user_dir=solomon_sonders

One shot where I moved the camera more than I should have...

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Thanks.

Why Av outdoors instead of continuing with M mode?

Do you set the exposure at -2 to 3 because you like the darker background? If you go with a 1/30 shutter speed, and assuming this is slower than hand hold recommended speed, will the flash compensate for the slower speed and help reduce the risk of "camera" shake induced blur. Are you simply using the shutter/aperture to expose the ambient light and let the flash determine the fill?

Do you use the -1/2 stop on FEC because that is where you have determined the flash gives you your desired effect? I assume the 0 setting at FEC provides too much light.

I appreciate the insight.

I'm kindof a creature of habit, if things are working ok I let them be.

I use the -1/2 flash exposure comp because it has a look I like a little more than full flash.

I use AV outdoors because I'm kinda lazy and its just works well to let the camera sort out the exposure and use the flash for fill. I can worry about posing more that way. The -1/2 flash exposure comp seems to works better outside too. The fill gives a little extra "pop". Use the "high speed sync (H)" function on the flash outside.

Inside I use a slow shutter and let the flash fill in. In the photo I posted you can see the lights in the background "streak" where the camera is moving but the forground is frozen because its mostly lit from the flash. You can get some strange movement effects from the ambient light sometimes but they are rare. The -2 background is just a guess. my shutter is usually 1/15 -1/60 and apeture f4.0 -f8.0 is what I shoot inside. I open wide for couple's headshots to blur the background out. I'm usually at iso 400 inside. I check the histogram more frequently than I should when shooting to make sure things are OK and adjust as needed.

Hope this helps.

There is a tutorial by Chuck Gardener on canon flash which might be helpful too. I use a similar technique which I learned elsewhere, but he explains it well.

http://super.nova.org/DPR/Canon/Exposure/

Thanks arammc. I shot a few test shots in the house with the kids tonight changing iso, aperture, EC, and FEC. I decided recently to learn more about using flash and I had read some of the link you included. I appreciate the insight from your experience.