autofocus challenges

Joined: 05 Jul 2006 Posts: 13 Location: Melbourne

Hi there everyone - can I please have some advice.

I do a lot of ballroom dancing photography of my children. I use Canon 350D with the kit 75-300 telephoto. The conditions are obviously difficult - fast movement in poorly-lit environment - most of the time some distance away and needing the full range of the telephoto lens.

To be able to stop the action I use ISO800, with exposure in the 1/125 to 1/160th.

When I get the right "alignment of stars", the results I get are very decent. However, the rate of rejections is extremely high, as most shots end up being anywhere from a little soft to quite a bit out of focus.

The autofocus obviously is having a hard time coping with these conditions.

I've tried different autofocus settings, but still have not come up with a way to improve my success rate. The movement is too fast for me to be able to effectively use manual focus.

Does anyone have any pearls of wisdom to experiment with? Is this an issue with my hardware? Would using more expensive lenses for example produce more precise focussing?

Many tnx in anticipation.