Help a camera illiterate

Hi

I have a canon 400D and have found that the flash it not to great when taking indoor photo's so on the weekend at a function in a large hall I had the camera set to night portrait and all the photo's came out with some kind of distortion.
I may be answering my own question but I think it may have been because I had the focus set to multi point ( if thats the term ) and this was causing the shutter speed to open for up to 2 seconds on some of the photo's I am uploading the photo's to my webshots page if anyone wants to view them and give me their expert opinion or if you think this information here is enough please advise me on whats best to take a good indoor photo

http://entertainment.w​ebshots.com/album/5635​17862gITPqW

Your focus points will have nothing to do with your exposure. It is the metering that has gone wrong and inevitably with an auto scene mode the camera will mostly guess at the settings it thinks is right. In photo 0094 for example, the shutter speed is too long by the looks of it. The camera has illuminated the people with a 1st curtain flash and then held the shutter open for another second which lets in the stray light and causes the light trails due to your movement. To combat this forget about the scene modes and turn the camera to Av, Tv or M mode. M is probably the easiest (dont be scared of it). Set a wide aperture and a shutter speed that is at least higher than your focal length i.e. 50mm lens should be 1/50sec or, preferably, a bit faster (this is a general rule of thumb that can be applied elsewhere). Push your iso up until your meter tells you that the exposure is good and then your flash should help to fill in the shadows.
Have a play around with these settings, leave behind the auto settings and you'll hopefully see improvements with your photos.

And welcome to POTN. There's tons of photographers here and we're all happy to help at any time.

Try this for the background base exposure: First set the f-stop & shutter speed you need. Then adjust the ISO.
Need an exposure crutch?

How the subject affects the exposure & why manual keeps me worry free:
Post #47

I always shoot in M when doing indoor flash photography. Using Av mode (or any other mode) I just don't get a fast enough shutter speed. I use an external flash but the onboard should work OK most of the time.