Testing the Sigma Lens
I bought the lens as a gamble on eBay for £30 inc postage and as an EF lens it ought to work on the Canon 300D. The seller reckoned it was working on his 450D. Bought "as seen" it worked at first but not on all modes.
Then on a trip out it didn't work at all! I chucked it in the back of the car and rescued it to give it a go. Maybe the thud in the car did something as it started working in P and Av modes.