Help for a novice please

[gpocock]

Hello

I normally take landscape pictures but next weekend I am going to a diamond wedding dinner and have been asked to take a few informal photographs. I have read the FAQ on flash photography and looked around the net. I have taken some shots in my study and they seem OK but I am uncertain which lens to use.

I have a 350D with an 430EX flash and a choice between a Canon 17-85 IS and a Sigma 17-70. For most work, I prefer the Sigma - better IQ, far less distortion and CA. But I believe that I will get better pictures if I underexpose the background by a couple of stops and use the flash for the main light. So, rather than shooting on Manual at, say F8 at 1/200sec, I should slow the shutter to perhaps 1/10sec. With the IS I can probably do this but not with the Sigma.

Or should I just shoot at 1/200sec.

I should add that a tripod is not acceptable.

Any comments most gratefully received

Best Wishes

Geoffrey Pocock

[Wilt]

1. Decide what f/stop you want to use
2. Take an ambient light reading and note what shutter speed would give correct full exposure.
3. With camera on M, put the shutter so that you capture ambient with -1EV or -1.5EV
4. With the flash on ETTL and with FEC +2/3EV dialed in, shoot

If #3 gets you to a shutter speed which is too slow, change #1 as necesssary to get #3 where you feel comfortable, or else abandon the idea of capturing ambient and ignore the b/g ambient lighting.

[Curtis N]

My hunch is that the image stabilization will have limited value in that situation, in that focal length range. Subject movement is likely to be what determines your minimum shutter speed.

[gpocock]

Hello

Tank you both for your helpful replies. Curtis N's point about image stabilisation is well-made; probably no use at all. Therefore go for the Sigma lens and follow Wilt's suggestions.

Best wishes

Geoffrey Pocock

[SkipD]

When using a Speedlite indoors doing candid shots of people, I have found that, using my 20D and 420EX, the P mode usually works quite well. I generally get decent exposure of the background as well as great flash exposure of the people in the foreground.