Flash beginner - need advice 580ex outdoor shooting

[Needsnow]

I am a beginner with using an external flash. As my schedule would have it, I have been asked to shoot an outdoor 90th birthday party this weekend. I will be using 2 lenses my Tamron 28-75 & 70-200.

I just got the flash yesterday, so I am on a really tight learning curve. I think that it would be better to use a flash outdoors in the shade, then not, so I have a few questions.

1) My Tamron lens doesn't communicate to the flash, so I need to manually press zoom and adjust the flash to match my lens focal length right?

2) For the best results, should I use the catchlight panel, if I am close to the subject?

3) Can I just keep the camera on P and watch my histogram to see if I need to turn the flash exosure up/down?

Any advice on helping me get through this weekend with my new flash is most appreciated. Thanks in advance!

[Big Mike]

1) My Tamron lens doesn't communicate to the flash, so I need to manually press zoom and adjust the flash to match my lens focal length right?
My flash (430EX) on my 20D with my Tamron lens...zooms just fine on it's own.

2) For the best results, should I use the catchlight panel, if I am close to the subject?
Only if you are bouncing the light off of something. Seeing as you will be outdoors...that's not likely. So no, you probably won't need the pull out panel.

3) Can I just keep the camera on P and watch my histogram to see if I need to turn the flash exosure up/down?
I'm not sure how your camera & flash will handle the shutter speed. Firstly, in normal mode, the flash may not illuminate properly with a shutter speed that is faster than your camera's max sync speed. So you would need to watch the shutter speed...maybe even shoot in Tv. This may mean small apertures in bright light. Small apertures means a large DOF and a lot of flash power consumed.
Alternatively, you could use the flash in 'High Speed Sync' mode...which can be used with faster shutter speeds...but it reduces the range of the flash and uses up the batteries a lot faster. The choice is yours.

[Curtis N]

Yep, the flash will zoom with any lens just fine, and for outdoor fill just point it straight ahead and shoot.

P mode will probably work fine. The camera will select a shutter speed 1/200 or slower and select an aperture for good ambient exposure. If it's sunny, use ISO 100. If it's cloudy, maybe ISO 200 or 400 depending on how thick the clouds are. Watch your shutter speed and aperture and adjust the ISO to keep them in an acceptable range. With practice, you'll want to have more control and maybe switch to Tv or M mode, but P mode is ok for your first time out, while you worry about other things.

Chimp often and adjust your Flash Exposure Compensation to get the right balance of subject exposure vs. background. Start with FEC somewhere around -1/3 or -2/3 and go from there.

[Needsnow]

Ok. I'll try that for the next couple of practice days. Thank you Curtis N. I'm going to have a look at your links in your signature!